Digital Cellular Modem-100 (DCM-100B) Battery-Powered, SNI-III Based. User s Guide

Transcription

1 Digital Cellular Modem-100 (DCM-100B) Battery-Powered, SNI-III Based User s Guide Document: Revision: C May, 2004

2 WARNING This product contains a radio-frequency transmitter, Motorola Model g18, FCC ID # IHDT6AC1 or Motorola Model c18, FCC ID # IHDT56CW1. This device must be installed in a manner that provides a minimum separation distance of 8 (21 cm) or more between the antenna and persons to satisfy FCC RF exposure requirements for mobile transmitting devices. See Chapter-9 for more safety information. WARNING No hazardous area safety approvals have been received for this product. It is therefore necessary to ensure that the product is only installed at locations that are classified as safe area sites. See Chapter-9 for more safety information. COPYRIGHT 2004 by Metretek, Incorporated All rights to this document, domestic and international, are reserved by Metretek, Incorporated. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of Metretek, Incorporated. Requests for permission to reproduce or distribute this manual should be addressed to: METRETEK, INCORPORATED 300 NORTH DRIVE MELBOURNE, FLORIDA, USA ii

3 COMMON QUESTIONS What does this device do? There are thousands of remote electronic devices installed around the world that communicate with central computers to report alarm conditions, unload collected data and receive new instructions. Examples include traffic control systems, gas, water and power meters, irrigation controllers and security systems. In many cases these devices contain internal modems connected to traditional wired phone lines. At the central office other modems connect to a central computer and a specific application program controls the entire operation. In very remote locations the cost of running phone lines over long distances can be quite high. The cost of wired phone service continues to increase, and in some hazardous areas telephone lines are not permitted at all. In these cases there have been several wireless solutions available such as analog cellular phone service or CDPD, which is a method of transferring digital information over analog cellular networks. However the limited capacity of analog cellular technology has led to the development of digital methods to increase capacity and provide new features. Some service providers have discontinued or greatly decreased the availability of analog cellular service. Some providers have abandoned it altogether in favor of digital-only systems. Metretek s DCM-100B and an application program called InvisiConnect offer a way to use modern digital cellular networks and the Internet to provide a reliable, cost effective and seamless path between the equipment in the field and the central computer. Few if any changes are required to the existing field equipment or to the existing application program and computer. See Chapter-1 for more information. What equipment can be used with the DCM-100B? Nearly any device that has a serial RS-232 port can be connected to the DCM-100B. A minimum of three wires is needed to carry data between the two units. Baud rates from 300 to are supported with hardware and software handshaking. The DCM-100B can emulate a traditional AT modem if the user s equipment is expecting a modem to be present. Using an optional adapter board called a dual-port multiplexer, two separate devices can be connected to the same DCM-100B. The devices do not have to be similar to each other and can operate at different baud rates, handshake settings and protocols. Metretek also manufactures a family of electronic devices for measuring gas flow, volumes, pressure and temperature in a gas system. These devices are often referred to as gas volume correctors and are marketed under the names AE-6000 or MTEK The 6000-Series correctors follow a communications standard called MODBUS. In a special mode the DCM-100B allows a corrector to communicate with a computer running Metretek s powerful data collection application called DC In this mode only one corrector can be connected to the DCM-100B. See Chapter-1 for more information. iii

4 Does the DCM-100B use a cell phone? The cellular radio module is similar to that used in a digital cellular phone, but there is no display, keypad, speaker or microphone. Instead it has a communications port that allows the DCM- 100B s processor to control the radio and use it as a wireless modem. Also, the radio is designed for more severe environmental conditions than a commercial cell phone. There are references within this document to mobile devices because the cellular radio system was intended to support portable phones and equipment. Though the DCM-100B is normally installed in a fixed location, it is still classified as a mobile device. How is the DCM-100B packaged? All circuit boards and batteries are mounted within a fiberglass NEMA 4X rated enclosure. This enclosure has built-in mounting holes and a latch that can be locked. All exposed fasteners are made of stainless steel. This enclosure is designed for outdoor environments and can withstand wide variations in temperature and humidity. Does it matter where the DCM-100B is installed? Since the DCM-100B contains the equivalent of a cellular phone it has the same limitations with respect to metal buildings and sources of radio interference. An optional external antenna kit is available that may overcome some of these problems. Also, and this is very important, although the equipment that will be attached to the DCM-100B may be allowed to operate in hazardous areas, the DCM-100B itself must not be installed in any area classified as hazardous. The use of safety barriers may be necessary. Is the DCM-100B ready to use immediately? No, there are four important steps before the DCM-100B can be put into service: 1) The field device must be wired to the DCM-100B (Chapter-2). 2) You must purchase cellular phone service (Chapter-4). 3) You must configure the DCM-100B using a computer and a special program and cable from Metretek (Chapter-5). 4) If using a 6000-Series corrector the data collection software supplied by Metretek (DC- 2000) must be supplied with information about the corrector (Chapter-7). If using InvisiConnect there are several simple parameters that need to be defined concerning the communications port on the computer (Chapter-6). How do I purchase cellular service? As with any cellular phone, you must purchase cellular service. There are several different digital technologies used today, and the service providers may support one or several of them. When you purchase a personal cell phone, you generally choose a provider that has the best calling plan and coverage in the area you live or work. You then receive a phone that works with their technology. The DCM-100B is designed to support GSM or CDMA technology. Though all service providers support voice calls, not all of them may support the exchange of data. Therefore it is necessary iv

5 to locate a service provider that supports circuit-switched data (CSD) connections or Internet connections using the general packet radio standard (GPRS) for GSM service, or single carrier, radio transmission technology (1X or 1XRTT) packet service for CDMA. Chapter-4 will help with this process. Why must the DCM-100B be configured? When the DCM-100B places a cellular call, it must have a phone number to dial or an Internet address to contact, instructions about what to do if the line is busy, what baud rate to use, etc. Each DCM-100B must also be assigned a unique ID number. The DCM-100B is configured using your computer and a special cable and software supplied by Metretek. This can be done any time before, during or after installation. Chapter-5 has much more information. What does InvisiConnect do? Your original application program is probably expecting a modem to be attached to one of the communications ports on the computer. The program may be waiting for a call from the field device, or may place a call to the device. Once connected, the computer and the remote device exchange information directly with each other through their modems. InvisiConnect has two major functions. First, it is a communications port emulator that allows your application program to work as it did before, even though there is no physical port or modem present. Second, InvisiConnect communicates with the DCM-100B over the Internet using digital cellular technology as the data link. The session between the remote device and your application program is nearly identical to a traditional modem setup, and neither end knows the difference. What does the DC-2000 data collection software do? When the field device is a 6000-Series corrector, Metretek s data collection software, DC-2000, has the ability to process calls from, or place calls to thousands of units. Each meter can be scheduled to call in at specific times throughout the day, or once a week or once a month. The data collection software can process the meter s information in many different ways, depending upon the customer s needs. It can also notify the customer immediately when an alarm condition occurs. To do this properly, each meter must be registered with the software. Chapter- 7 has much more information. v

6 What is the difference between CSD and Packet Service? When the DCM-100B places or receives a CSD (circuit-switched data) call, it will be communicating with an analog modem that is tied to a wired telephone line. The cellular service provider has banks of modems available in its switching centers. When it detects a CSD call, it connects one of its own modems to the wired line. Data is transferred between the DCM-100B and the switching center via the radio link, and then between the switching center and the destination modem via wire. Like a voice call, a CSD call is generally billed by the minute. Some service providers may only support mobile-originate calls, meaning the DCM-100B can place a call but cannot be called. GSM cellular service providers may offer access to the Internet using a service called GPRS (general packet radio service). CDMA cellular service providers may offer access to the Internet using a service called 1X or 1XRTT (single carrier, radio transmission technology). Data is exchanged in small blocks, or packets, to a server running Metretek s DC-2000 or InvisiConnect software. A packet call is generally billed by the amount of data exchanged rather than by the minute. Service is generally purchased in increments of 1 million bytes (1Mb) per month. Packet service has the advantage of being able to retrieve data from any DCM-100B regardless of how far away the unit is from the central computer, without the expense of long-distance phone calls. At the present time the DCM-100B itself can communicate using CSD or packet service. When using InvisiConnect, only packet service is supported. vi

7 TABLE OF CONTENTS 1 PRODUCT DESCRIPTION Product Overview Communications Options Communications Scenarios CSD versus Packet mode INSTALLATION Unpacking, Damage reports, Item List Additional Items Required for Installation Site Selection for Best Performance DCM-100B Layout DCM-100B Block Diagram SNI-III Controller Board Power Supply Board Wiring Typical Field Devices to the DCM-100B Wiring a 6000-Series Corrector to the DCM-100B Lead Acid Battery Installation External Antenna Kit Installing the Optional Dual-Port Multiplexer Battery Replacement Quick Power-Up Check CONFIGURATION OF A 6000-SERIES CORRECTOR Series Corrector Operation Manuals Corrector Firmware Level Corrector Processes Changes to the Corrector s MODBUS parameters Changes to the Corrector s SYSTEM parameters Changes to the Corrector s DIALER parameters Changes to the Corrector s EEPROM parameters CELLULAR SERVICE GSM Service GSM Overview Establishing Cellular Service for GSM GPRS Packet Service Establishing Cellular Service for GSM CSD SIM Card Installation Requesting a Voice Phone Number or SMS Service CDMA Service CDMA Overview Establishing Cellular Service for CDMA 1XRTT Packet Service Establishing Cellular Service for CDMA CSD Requesting a Voice Phone Number or SMS Service Over-the-Air Activation CONFIGURATION USING METRETEK PROGRAMMER Metretek Programmer Cable MP32 Software Startup Main Configuration Screen Remote Unit ID Destination Originate Calls vii

8 5.3.4 Respond to Voice Calls Respond to SMS Maintain Internet Connection Dual Port Firmware Version Primary Call Retry Rate Primary Call Retry Count Secondary Call Retry Interval Alarm Input 1 & Serial Port-1 Screen Port Select ID Max BPS Flow Control Wait ms before sending packets Maximum Packet Size Data Bits Parity Type Stop Bits Always Send Connect Message Always RING Port Use Non-verbose Result Codes Override CONNECT Message Serial Port-2 Screen Cellular Settings Screen Service Type PIN Number Frequency GPRS Access Point Name (GSM only) Packet Service Connection Command OTA Programming Number (CDMA only) PAP User Name and Password Programming the DCM CONFIGURATION OF INVISICONNECT Introduction InvisiConnect License Agreements Flow Control (Handshaking) InvisiConnect Modem Emulation Details ATV (response type) Command ATE (echo) Command ATZ (default settings) Command ATH (hangup) Command ATA (answer) Command ATD (dial) Command (escape) Command ATO (online) Command All Other AT Commands AT Command Chaining Normal Responses to AT Commands InvisiConnect Configuration External IP Address viii

9 6.5.2 Server Configuration and Control User Application Interface IP Port Number Server Description Auto Start Server At Startup Wait ms before sending packets Maximum Packet Size Use Packet Concatenation Close Connection after Minutes Latency Compensation Fast Loop-Back Response Block Transmit Tickle Hold-Off Force Connect Message Latency Limit Com Port Configuration Adding COM Ports Defining COM Port Settings MODEM Emulation Settings InvisiConnect Trace and Alarm Files SMS/USSD Configuration Enable SMS Use SMTP Mail Server SMTP Server Address From Display Name From Address Use Attached Cellular Modem Cellular Modem Com Port Flow Control Baud Rate, Data Bits and Stop Bits Keep COM Port Open Modem Reset and Initialization Strings SMS / USSD Prefix and Suffix Override Call-Back IP Address Remote Device Configuration Changes General Information Connection Information Last Reported Signal Strength Firmware Version Change APN Address SMS Address Callback IP Address and Port SMS Now IP Address Call Schedule / Retry Strategy PAP / Latency / Blocking PAP User Name and Password Latency Limit Blocking Line Control / Port Selection DSR Control ix

10 Port Select / DCD Line Control Saving and Loading Configurations Normal InvisiConnect Operation and Indicators Terminating a Connection with a Field Device DC-2000 DATA COLLECTION SYSTEM Introduction Setting up the MODBUS Server Setting up a Call Schedule Defining the 6000-Series Corrector MODES OF OPERATION Call Retry Strategy Repetitive Call-In Schedule Controlling the Flow of Data from the Field Device Hardware Handshaking Software Handshaking None Custom # Custom # End-of-Message Determination AT Modem Emulation ATV (response type) Command ATE (echo) Command ATX (connect message type) Command ATH (hangup) Command ATA (answer) Command ATD (dial) Command (escape) Command AT Command Chaining Paging via Voice Call Paging via SMS Message What Causes the DCM-100B to Call In? Initial Power Up or Reset Alarm Tamper Alarm Call Retry Alarm AC-OFF Alarm AC-ON Alarm Call Switch Alarm Alarm Input # Alarm Input # Paging Activation of the DTR Line Reception of an ATD Command Repetitive Call-In Time Interaction with the Field Device Response to an ATD (dial) Command Response to the DTR Line Going Active Calls Originated by the DCM-100B Response to +++ Escape Sequence Behavior when Originating a Call in CSD Mode Behavior when Answering a Call or Page in CSD Mode Behavior in Packet Mode x

11 8.13 Permanent ( Always On ) Internet Connection Alarm Status and Maintenance in CSD Mode Dual Port Operation Port Selection Guidelines Using the DTR Line in Dual Port Mode Low Battery Standby Mode SAFETY, HAZARDOUS AREAS, ESD PRECAUTIONS TECHNICAL SPECIFICATIONS ASCII-HEX-DECIMAL CONVERSION CHART WARRANTY INFORMATION LIST OF TABLES SNI-III Circuit Board Jumper Configuration External Antenna Kits Corrector s MODBUS Parameters Corrector s SYSTEM Parameters Corrector s DIALER Parameters Corrector s EEPROM Parameters Normal Responses to AT commands Common CONNECT Responses DCM-100B AT Responses CSD Mode Status Commands LIST OF FIGURES Data Collection System using CSD Traffic Information System using the Internet Metretek Programmer Cable Primary Components of the DCM-100B Enclosure Dimensions DCM-100B Block Diagram SNI-III Controller Board Block Diagram of the SNI-III Board Power Supply Board Minimum Connection of a Field Device to the DCM-100B Handshake Connection of a Field Device to the DCM-100B Connection of a 6000-Series Corrector to the DCM-100B Installation of the lead acid battery Lead acid battery after installation Optional External Antenna Accessory Kit Dual Port Multiplexer Board Installed Dual Port Multiplexer Board Externally-Mounted Dual Port Multiplexer Board Typical Wiring of Two Field Devices to the Multiplexer Board SIM Card Profile SIM Card Installation MP32 Login Screen MP32 Start-Up Screen xi

12 Communication Port Configuration Screen Main Configuration Screen Screen Image with Serial Port 1 Tab Selected Screen Image with the Cellular Settings Tab Selected InvisiConnect Main Screen Server Configuration Screen Fast Loop-Back Response Screen Block Transmit Screen Tickle Hold-Off Screen Force Connect Message Screen Latency Limit Screen COM port Configuration Screen InvisiConnect Trace Configuration Screen SMS/USSD Settings Screen Connection Info Change Screen IP Address Change Screen Call Schedule / Retry Strategy Change Screen PAP / Latency / Blocking Change Screen Line Control / Port Selection Change Screen Terminating a Connection with a Field Device Starting the System Configuration Changing the Data Collection Configuration Configuring the MODBUS Server Configuring a Call Schedule Defining a Call Profile Name Defining the Call Profile Parameters Starting the Corrector Configuration Process Defining a New Corrector Defining the Corrector s Setup List of all Correctors in the System Custom #2 Flow Control DCM-100B s LED Indicators xii

13 1.1 Product Overview 1 PRODUCT DESCRIPTION There are thousands of remote electronic devices installed around the world that communicate with central computers to report alarm conditions, unload collected data and receive new instructions. Examples include traffic control systems, gas, water and power meters, irrigation controllers and security systems. In many cases these devices contain internal modems connected to traditional wired phone lines. At the central office other modems connect to a central computer and a specific application program controls the entire operation. In very remote locations the cost of running phone lines over long distances can be quite high. The monthly cost of wired phone service continues to increase, and in some hazardous areas telephone lines are not permitted at all. In these cases there have been several wireless solutions available. Analog cellular phone service has been used to exchange modem signals in much the same way as it does with voice signals. Another method was developed call CDPD, which is a method of transferring digital information in packets over an analog cellular network. However the limited capacity of analog cellular technology has led to the development of digital methods to increase capacity and provide new features. Some service providers have discontinued or greatly decreased the availability of analog cellular service. Some providers have abandoned it altogether in favor of digital-only systems. The DCM-100B was specifically designed to address these problems. Operating as a wireless transparent modem, the connection is made using commercial digital cellular GSM or CDMA phone networks. The DCM-100B supports 900 / 1800 / 1900 MHz GSM, used throughout most of the world. It can make a circuit-switched data (CSD) connection to another modem, or a general packet radio service (GPRS) connection to an Internet server. Another version supports 800 & 1900 MHz CDMA service. It can make a circuit-switched data (CSD) connection to another modem, or a single carrier, radio transmission technology (1XRTT) connection to an Internet server. Nearly any device that has a serial RS-232 port can be connected to the DCM-100B. A minimum of three wires is needed to carry data between the two units. Baud rates from 300 to are supported with hardware and software handshaking. The DCM-100B can emulate a traditional AT modem if the user s equipment is expecting a modem to be present. On the computer end is a special application program called InvisiConnect. Your original application program is probably expecting to communicate with a modem attached to a communications port on the computer. InvisiConnect has two major functions. First, it is a communications port emulator that allows your application program to work as it did before, even though there is no physical port or modem present. Second, InvisiConnect communicates with the DCM-100B over the Internet using digital cellular technology as the data link. The link between the remote device and your application program is nearly identical to a traditional modem setup, and neither end knows the difference. Metretek also manufactures a family of electronic devices for measuring gas flow, 1-1

14 volumes, pressure and temperature in a gas system. These devices are often referred to as gas volume correctors and are marketed under the names AE-6000 or MTEK The 6000-Series correctors follow a communications standard called MODBUS. In a special mode the DCM-100B allows a corrector to communicate with a computer running Metretek s powerful data collection application called DC-2000 using the MODBUS protocol. 1.2 Communications Options Selecting a communications network to reliably transfer data is a great challenge. Economic factors come into play where the initial product cost must be weighed against monthly network service charges. Some points to consider when selecting a network are: - Satellite or microwave data links have a high initial cost and a high ongoing cost to maintain the service. Advantages include high reliability and high bandwidth (fast data transfers). - Wired telephone line connections with a modem circuit are the most common for costsensitive applications. Installation and operation costs depend upon how accessible a phone line is at the site, whether the line is dedicated or shared, and whether the calls are local or long distance. - Analog cellular phone service has been used in areas where phone lines do not exist. While the initial purchase price of the service can be higher than that of a wired line system, it eliminates the expense of running telephone wires over long distances. In some hazardous sites, telephone lines are not permitted. However, the limited capacity of analog cellular technology has led to the development of digital methods to increase capacity and provide new features. Some service providers have discontinued or greatly decreased the availability of analog cellular services. Some providers have abandoned it altogether in favor of digital-only systems. - Digital cellular networks are rapidly expanding and replacing earlier analog systems. More efficient use of the radio spectrum permits the network to handle many more calls at a given time, and to offer new features including data exchange. In the case of the DCM-100B, a GSM or CDMA cellular phone link is utilized to provide the most economical and reliable solution. Figures 1-1 and 1-2 provide simplified illustrations of the network from end-to-end. 1-2

15 Figure 1-1 Data Collection System using CSD Figure 1-2 Traffic Information System using the Internet 1-3

16 1.3 Communications Scenarios Scenario #1: The DCM-100B initiates a call to the central computer The DCM-100B determines that a call should be made due to an alarm condition, a regularly scheduled call event or a call request from the field device. The cellular radio on the DCM-100B establishes a connection with the cellular phone network. The DCM-100B initiates an outbound data call (CSD mode) or Internet connection (packet mode) to the central computer, which is running Metretek s InvisiConnect or DC-2000 data collection software. In the case of DC-2000, the central computer processes the meter s data and stores it in a database structure format. In the case of InvisiConnect, data originating from your application program is passed on to the field device, and visa versa. Scenario #2: The data collection computer initiates a data call to the DCM-100B (CSD mode only). The DCM-100B cellular radio is registered with the cellular network, and is therefore always listening for an incoming call. The central computer dials the radio s data number (this is known as a mobileterminate CSD connection). When the radio answers the call, it will establish a link with the computer, which is running Metretek s DC-2000 data collection software (InvisiConnect does not support CSD calls). The computer processes the meter s data and stores it in a database structure format. Scenario #3: The data collection computer pages the DCM-100B and waits for the DCM-100B to call back. NOTE: It is not possible to contact the DCM-100B via the Internet because mobile devices do not have permanent Internet addresses. In CSD mode the cellular service provider may not support mobile-terminate connections. In these cases the DCM-100B can be paged, which will cause the unit to call back immediately. The DCM-100B cellular radio is registered with the cellular network, and is therefore always listening for an incoming call or message. If the cellular account has been assigned a voice or data phone number, the computer calls that number. The DCM-100B answers the call, hangs up, and will immediately call back as described in Scenario #1. 1-4

17 If the cellular account includes a feature called SMS (short message service), the computer can send a text message to the DCM-100B. When the DCM-100B receives the message it will immediately call back as described in Scenario # CSD versus Packet mode The DCM-100B can communicate with the central computer s modem using a circuitswitched data (CSD) connection, or can exchange information with the central computer over the Internet. There are advantages and limitations to each method. CSD mode is similar to two modems communicating over a wired telephone line. The cellular service provider has banks of modems available in their switching centers. When it detects a CSD call, it connects one of its own modems to the wired line. Data is transferred between the DCM-100B and the switching center via the radio link, and then between the switching center and the destination modem via wire. Cellular service providers often offer this service as an add-on package to a standard voice account, and each call is measured and billed in terms of minutes used. Depending upon the frequency and length of the calls this service can become quite expensive. In situations in which the calls are long distance, it may be possible to purchase plans that include free long distance in order to reduce costs. GSM cellular service providers may offer access to the Internet using a service called GPRS (general packet radio service). CDMA cellular service providers may offer access to the Internet using a service called 1X or 1XRTT (single carrier, radio transmission technology). Data is exchanged in small blocks, or packets, to a server running Metretek s DC-2000 or InvisiConnect software. Cellular service providers may offer this service as an add-on package to a standard voice account, or may offer it as a stand-alone product. Each connection is usually measured and billed in terms of the amount of data exchanged, usually in increments of 1 million bytes (1 Mb) per month. The amount of information exchanged on each call may range from several hundred bytes to 10 s of thousands of bytes, depending upon the information that is requested from the field device. It may be necessary to test the system for several months and then adjust the cellular account for the best cost based on your needs. 1-5

18 1-6

19 2 INSTALLATION 2.1 Unpacking, Damage reports, Item List Upon receipt, inspect the DCM-100B for any potential shipping damage. If any damage is detected that can be attributed to the way the package was handled, then a claim should be filed with the shipping agent as quickly as possible. A typical DCM-100B is provided with the following items: The SNI-III controller board Motorola g18 cellular radio module (mounted to the SNI-III board) Antenna (mounted to the radio or externally mounted to the side of the enclosure and connected to the radio) Power supply board 6-volt, sealed lead-acid battery 6-volt alkaline lantern battery (for charging the lead-acid battery) Nema 4X enclosure Manual (this document). Normally only one manual is included with each shipment rather than with each unit. Additional manuals can be ordered separately or obtained in PDF file format upon request. Note: The items listed above may vary depending on what was requested with the original purchase order. Refer to the shipping document or the purchase order for a precise record when inspecting the package contents. 2.2 Additional Items Required for Installation Several additional tools and items will be required before proceeding with the field site installation. These are: Equipment available from Metretek: PC-to-serial link (Metretek programmer cable) as illustrated in Figure 2-1. This item can be obtained under stock number B-001. MP-32 programmer software application program, available under Metretek stock number If the field device is a 6000-Series corrector it will need a special communications cable, Metretek stock number C-xxx, where xxx is the customerspecified length. See Section 2.9 for wiring instructions. 2-1

20 Figure 2-1 Metretek Programmer Cable Common off-the-shelf items required for installation: x86 or Pentium class laptop computer for configuration of the DCM-100B. The operating system must be Microsoft Windows-98 or newer. The computer must have a serial port available. An activated SIM card to enable the GSM cellular radio module. This must be obtained from the cellular service provider. Refer to Chapter-4 for additional details regarding SIM card activation. CDMA does not require a SIM card but an account must be established before the radio can be activated. Voltmeter for troubleshooting. Hand tools, fasteners, mounting hardware, PVC pipe, etc. 2.3 Site Selection for Best Performance WARNING No hazardous area safety approvals have been received for this product. It is therefore necessary to ensure that the product is only installed at locations that are classified as safe area sites. See Chapter-9 for more safety information. Field site selection for a cellular communications product requires additional consideration with regard to antenna placement. Ensure that the antenna is pointing in a vertical direction. Mount the unit away from buildings and structures when possible. Buildings tend 2-2

21 to block the rf signal if they lie in the path between the cellular tower and the DCM-100B. Outdoor installations are preferred Raise the elevation as high as practical from the ground. Avoid mounting the unit to the side of a metal shed or similar structure since metal is a very effective shield against the desired rf signal. Chain link fences are normally not a problem. Avoid mounting the product in a location where the antenna is in close proximity to a measurement instrument such as a Rosemont transducer. The strong R.F. field from the cellular module transmitter could possibly degrade the accuracy of these precision instruments. Conversely, nearby electronic equipment may interfere with the operation of the cellular radio. Depending on the signal strength for a given location, it may be possible to violate some of these suggestions and still obtain good performance. This will vary from one site to the next, just as the reception quality of a handheld cellular phone will vary. The DCM-100B has a built-in antenna. If the antenna provided does not provide adequate performance, a different antenna can be used as long as it complies with the impedance and frequency range of the cellular radio module. For instance, the DCM- 100B may be located in a metal building but a mobile antenna, such as the type that would mount to the roof of a vehicle, may be located outside of the building. See Chapter-2 for more information. WARNING This product contains a radio-frequency transmitter, Motorola Model g18, FCC ID # IHDT6AC1 or Motorola Model c18, FCC ID # IHDT56CW1. This device must be installed in a manner that provides a minimum separation distance of 8 (21 cm) or more between the antenna and persons to satisfy FCC RF exposure requirements for mobile transmitting devices. See Chapter-9 for more safety information. 2-3

22 2.4 DCM-100B Layout The DCM-100B assembly is shown in Figure 2-2 and the enclosure dimensions in Figure 2-3. Figure 2-2 Primary Components of the DCM-100B 2-4

23 Figure 2-3 Enclosure Dimensions 2-5

24 2.5 DCM-100B Block Diagram Figure 2-4 DCM-100B Block Diagram 2-6

25 2.6 SNI-III Controller Board The Serial Network Interface III (SNI-III) circuit board assembly is shown in Figure 2-5. Components that are not related to installation are not shown. Figure 2-5 SNI-III Controller Board 2-7

26 Various jumpers exist on the SNI-III board to enable different operating modes and options. Table 2-1 lists these jumpers and their purpose. JUMPER POSITION NOTES J2 OPEN Momentary short will force the unit to originate a call JP3 A-B For applications that require the DSR control line to have RS- 232 voltage levels (± 9V) JP3 B-C For applications that require the DSR control line to have +5V and 0V voltage levels (use this setting if using a 6000-Series corrector). JP4 OPEN Momentary short will reset unit and clear data memory JP7 OPEN Used for factory testing Table 2-1 SNI-III Circuit Board Jumper Configuration Figure 2-6 Block Diagram of the SNI-III Board 2-8

27 2.7 Power Supply Board Figure 2-7 Power Supply Board The primary input source for the power supply board is typically a 6-volt alkaline lantern battery. Any other filtered dc supply can be used as long as the voltage does not exceed 6.5 V. The battery connects to the + and connections on the TB2 connector. The power supply board provides three functions. First, the board provides a regulated, low current (100mA) +5V supply for the SNI-III board. This connects to J3 on the SNI board. It is the primary source when the radio is not being used. When the radio is powered up the SNI-III generates a signal on its J9 connector that causes the power supply board to enable a high-current +5V supply. This supply is coupled to the J3 connector on the SNI-III board. This supply is needed due to the high current demands of the radio. The third function is to supply a constant 6.3V charging voltage for the lead acid battery. It is this battery that supplies most of the current for radio operations. The alkaline battery is simply a charging source. 2.8 Wiring Typical Field Devices to the DCM-100B The field device must have an RS-232 serial port. A minimum of three lines is required for the simplest connection: a line to transmit data to the DCM-100B, one to receive data from the DCM-100B, and common. This is shown in Figure 2-8. There may be a need to control the flow of data between the two devices. This is commonly referred to as handshaking and one method is known as hardware handshaking. The connections are illustrated in Figure 2-9. See Chapter-8 for a more detailed discussion about the connection and handshaking. The DCM-100B also has provisions to accept up to four Form-A (normally open) switches. Two of these can be used as alarm inputs and the DCM-100B can be programmed to place an immediate call when either switch closes. The General Alarm input is wired in parallel with the CALL jumper J2. Momentarily shorting this 2-9

28 connection will cause the unit to place an immediate call to the central computer if it has been configured to originate calls. Another, called TAMPER, can be used with a magnetic switch that detects when the enclosure s door is opened. The switch should close when the door opens and the unit will place an immediate call to the central computer if it has been configured to originate calls. Leave any of these terminals open if not needed. See Chapters-5 and 8 for more information about alarms. Figure 2-8 Minimum Connection of a Field Device to the DCM-100B 2-10

29 Figure 2-9 Handshake Connection of a Field Device to the DCM-100B 2.9 Wiring a 6000-Series Corrector to the DCM-100B A 6000-Series corrector is connected to the DCM-100B s serial port using a special cable, Metretek stock number C-xxx, where xxx is the customer-specified length. See Figure The serial port generates and accepts standard RS-232C (EIA) voltage levels. Output voltages can reach levels of ± 9V. If the corrector is to be located in a hazardous area, it may be necessary to use safety barriers between the corrector and the DCM-100B. The DCM-100B also has provisions to accept up to four Form-A (normally open) switches. Two of these can be used as alarm inputs and the DCM-100B can be programmed to place an immediate call when either switch closes. The General Alarm input is wired in parallel with the CALL jumper J2. Momentarily shorting this connection will cause the unit to place an immediate call to the central computer if it has been configured to originate calls. Another, called TAMPER, can be used with a magnetic switch that detects when the enclosure s door is opened. The switch should close when the door opens and the unit will place an immediate call to the central computer if it has been configured to originate calls. Leave any of these terminals open if not needed. See Chapters-5 and 8 for more information about alarms. IMPORTANT NOTE Refer to Figure 2-5 and Table 2-1. For corrector applications, the JP3 jumper must be set to the B-C position on the SNI-III circuit board. 2-11

30 See Chapter-3 for programming information for the corrector itself. See Chapter-5 for information about configuring the DCM-100B for use with a corrector. See Chapter-7 to properly configure the data collection software. Figure 2-10 Connection of a 6000-Series Corrector to the DCM-100B 2-12

31 2.10 Lead Acid Battery Installation A 6V, 3 Ahr sealed lead acid battery provides backup power and the brief but heavy current requirements of the cellular radio. The lead acid battery is shipped separately to prevent damage to the electronic components, and to satisfy regional rules regarding the shipment of hazardous materials. The battery is easily installed by removing two screws and elevating the mounting bracket as shown in Figure Figure 2-12 depicts the final assembly. Once the battery is installed, locate the two-wire cable with the white connector that is plugged into J1 on the power supply board. Follow these steps: 1) Unplug the white connector from the J1 connector on the power supply board. Grasp and squeeze the ears on the connector, then pull out. 2) Connect the red wire to the positive (+) terminal on the battery. 3) Connect the black wire to the negative (-) terminal on the battery. 4) Do not plug the white connector back in until reading the rest of this chapter. Figure 2-11 Installation of the lead acid battery 2-13

32 Figure 2-12 Lead acid battery after installation 2-14

33 2.11 External Antenna Kit You may encounter marginal reception areas or locations where buildings and other obstructions block the cellular radio signal path. The rigid internal antenna may not provide adequate performance in these situations. Provisions have been made to permit the installation of an external antenna. Figure 2-13 provides an exploded diagram of the components included with the kit (excluding the radio and enclosure). Figure 2-13 Optional External Antenna Accessory Kit Every DCM-100B enclosure has been pre-drilled with a 1/4" diameter hole at the upper left-hand side of the enclosure wall or on the door. It is necessary to push out the small black hole plug and clean away any residual silicon sealant. The SMA female end of the cable is then pressed through the enclosure wall and fastened into place using the provided washer and nut. When securing the antenna onto the SMA connector, ensure that the fitting is tightened sufficiently by hand (tools are not required), and that the antenna is vertically orientated. The opposite end of the cable with the MMCX connector end is pressed onto the mating connector of the Motorola cellular radio as shown. Three antenna kits are available depending upon the cellular frequency: Metretek Stock # Frequency MHz MHz MHz Table 2-2 External Antenna Kits 2-15

34 2.12 Installing the Optional Dual-Port Multiplexer The optional dual-port multiplexer board (Metretek Stock # ) allows two field devices to connect to one DCM-100B. For example you may have a traffic information sign and a digital camera mounted on the same pole. It would be possible to update the sign and gather images of traffic using only one DCM-100B. Figure 2-14 Dual Port Multiplexer Board Figure 2-15 depicts the multiplexer board installed directly on the DCM-100B. The pins of the multiplexer board are inserted into the DCM-100B s terminal block. All screws on the DCM-100B s terminal block must be tightened to ensure proper electrical contact. Connections are then made to the multiplexer board s terminal block for all alarm inputs as well as the serial connections to the two field devices. 2-16

35 Figure 2-15 Installed Dual Port Multiplexer Board If this mounting arrangement is not practical for your application then the multiplexer board can be mounted in another location using the two mounting holes on either end of the board. The J3 connector is used to connect the six interface lines to the terminal block on the DCM-100B. The J3 connector is a 6-pin MTA style male connector on 0.1 (2.54 mm) centers. The connector has a built-in polarity tab to prevent the mating connector from being installed incorrectly. A suggested mate is an AMP Do not exceed a cable length greater than 10 (3.3 m). See Figure 2-10 for the proper wiring. 2-17

36 Figure 2-16 Externally-Mounted Dual Port Multiplexer Board The DCM-100B must be informed that the dual-port multiplexer is installed. See Chapter-5 about this. The multiplexer can also be controlled remotely using the InvisiConnect software, discussed in Chapter-6. See Chapter-8 for additional information about using the multiplexer board in CSD mode. Figure 2-17 depicts a typical wiring diagram for two field devices. 2-18

37 Figure 2-17 Typical Wiring of Two Field Devices to the Multiplexer Board 2.13 Battery Replacement Battery life is affected by the frequency and duration of the cellular calls and ambient temperature conditions. See Chapter-8 for battery types. The battery charger board extracts energy from the lantern battery pack and transfers it to the lead acid battery. The lead acid battery is the reservoir used to provide the high currents required by the cellular radio module. The beginning voltage of a new lantern battery is about 6.3V. End of battery life is considered to be about 3.6V. The power supply board delivers a charging voltage of 6.5V to the lead acid battery at all times. When the lantern battery reaches its end of life the power supply board will generate a low-battery signal to the SNI-III board. Eventually the lantern battery will become too weak to contribute any further energy to the lead acid battery. The lead acid battery will gradually become depleted, and it will no longer be possible to place cellular phone calls. Further depletion of the lead acid battery will result in a deep discharge of the battery and will result in the loss of data in the DCM-100B. Battery voltage may drop in severely cold weather, and return to normal limits as it warms up. Occasional low-battery messages may not necessarily mean that the battery 2-19

38 needs to be replaced. However, repeated alarms could signal a weak battery and it should be replaced as soon as possible. a) Check the voltage of the lantern battery while it is in service, particularly just after a cellular call. This will be the time when the most current is drawn from the battery as it recharges the lead acid battery. Acceptable levels are from 6.3V down to 3.6V. b) Check the voltage of the lead acid battery while it is in service. A fully charged battery should measure about 6.5V while in standby mode. If the voltage drops below 6V during a cellular call, the lead acid battery may need to be replaced. Normal replacement cycle is every 2 4 years Quick Power-Up Check Disconnect the lead acid battery s cable from J1 on the power supply board. Attach the cable leading from TB2 on the power supply board to the alkaline lantern battery, observing polarity: red wire to + and black wire to -. The green PROGRAM MONITOR light should light solidly. The red RECEIVE DATA light should light momentarily, then go out. The green PROGRAM MONITOR light should then start flashing once per second. This indicates the DCM-100B is running. Disconnect the alkaline battery. Install the lead acid battery s cable into J1 on the power supply board. The green PROGRAM MONITOR light should light solidly. The red RECEIVE DATA light should light momentarily, then go out. The green PROGRAM MONITOR light should then start flashing once per second. This indicates the DCM-100B is running. Remove the connector from J1 until it is time to configure the unit (see Chapter-5). 2-20

39 3 CONFIGURATION OF A 6000-SERIES CORRECTOR NOTE: Proceed to Chapter-4 if you are not using a 6000-series Corrector IMPORTANT The DCM-100B must also be configured to work with a 6000-Series corrector. This is called the Custom #1 flow control setting. See Chapter-5 for more information. IMPORTANT The DCM-100B s JP3 jumper must be set to the B-C position to work with a 6000-series corrector. See Chapter-2 for more information Series Corrector Operation Manuals Information about the 6000-Series corrector s installation and operation can be found in Metretek Manual (MTEK-6000) or (AE-6000). There are several programming changes needed to operate with the DCM-100B, and those changes are described here. 3.2 Corrector Firmware Level The 6000-Series corrector must have a firmware version level of 2.00/04 or higher for the MTEK-6000 or 1.01/04 or higher for the AE-6000 in order to be used with the DCM- 100B. The firmware information is displayed upon power up, and is also located on a label on the program memory chip inside the unit. Contact Metretek if new firmware is required. 3.3 Corrector Processes The 6000-Series correctors are highly configurable. One model might measure only pressure while another might measure gas flow, temperature and pressure. One unit might make a measurement every 10 minutes while another once a day. The corrector s program is guided by a set of parameters (a database) that describes how the corrector should function. The database is generally loaded at the factory but can be fine-tuned by a user who has the proper equipment and training. See the 6000-Series operator s manuals or call Metretek for more information. The database is subdivided into specific functions called processes. Each process contains a number of items to describe the exact behavior of the corrector. Several processes require slight modifications to operate with a DCM-100B. 3-1

40 3.4 Changes to the Corrector s MODBUS parameters. The corrector supports an industry-standard communications protocol called MODBUS. Generally the MODBUS process is ready to use and does not have to be modified. However, here is a list of important items and how they should be configured: MODBUS Process Value Description Enable MODBUS process MODBUS device address RTU communications mode No parity Float register start address Float register end address Conversion base (CSD) or 90.0 (packet) Communications timeout (sec.) Enable mode Table 3-1 Corrector s MODBUS Parameters 3.5 Changes to the Corrector s SYSTEM parameters In wired phone applications the corrector can be called and can be programmed to answer the call on any number of ring signals. The process of detecting and counting ring signals takes a certain amount of processing time. Since the DCM-100B takes care of answering incoming wireless calls, the corrector should be instructed to skip this process by setting the ring count to 0. This parameter is located in the SYSTEM process: SYSTEM Process Value Description Disable ring detection Table 3-2 Corrector s SYSTEM Parameters NOTE: If you do not wish to change this parameter, then remove the RING DETECT jumper from the corrector s main processor board. Refer to the corrector s manual for the location of this jumper. 3-2

41 3.6 Changes to the Corrector s DIALER parameters The DIALER process is normally used to place a wired phone call. But in this application the corrector signals the DCM-100B to place a call using a phone number or Internet address that has been programmed into the DCM-100B (see Chapter-5). However, the corrector must still have at least one phone number digit to dial in order to start this process. The next table illustrates how to set a simple phone number of 9 into the 1 st alarm dialer process: 1 st ALARM DIALER Process Value Description Enable TONE dialing No access code No area code No prefix One phone number ( 9 ) No access code delay No area code delay No prefix delay One phone digit delay for 9. Table 3-3 Corrector s DIALER Parameters 3.7 Changes to the Corrector s EEPROM parameters The corrector uses a non-volatile memory device to store parameters not directly related to any other process. Some of these parameters deal with communications. The following two parameters will set the corrector to communicate with the DCM-100B: EEPROM address Value Description Enable direct port comms Direct communications baud rate Table 3-4 Corrector s EEPROM Parameters 3-3

42 3-4

43 4 CELLULAR SERVICE 4.1 GSM Service GSM Overview GSM is an abbreviation for Global System for Mobile communications. This communications standard is widely used throughout Europe, Africa, Asia and parts of North and South America. Messages are digitized into packets and sent in brief bursts during allocated time slots using a variation of TDMA (Time Division Multiple Access) techniques. Up to 8 cellular phones can thus share the same frequency band, which in turn permits the system to support more users with existing equipment. Efficient utilization of spectrum is an important consideration for service providers since there is only a limited bandwidth space that has been allocated to cellular phone service. Most GSM systems throughout the world operate on either the 900 MHz or 1800 MHz communications bands. In North America most GSM systems operate on the 1900 MHz band Establishing Cellular Service for GSM GPRS Packet Service A cellular account must be activated with a cellular service provider prior to placing a DCM-100B into service. Some GSM service providers may not offer all forms of data transfer. General packet radio service (GPRS) may have to be added to a standard voice plan, or may be a stand-alone service. GPRS packages are generally priced by the number of bytes to be transferred rather than by the minute. Typically the smallest available package will be 1 megabyte (1 Mb) per month. The amount of data that the DCM-100B will produce depends upon what sort of data is requested from the field device. The amount of information exchanged on each call may range from several hundred bytes to 10 s of thousands of bytes. It may be necessary to test the system for several months and then adjust the cellular account for the best cost based on your needs. In order to connect to the Internet, the cellular service provider has its own computer equipment called a gateway server, aptly named, as it is their gateway to the Internet. The server will have an APN (access point name), usually in the form of a domain name such as internetaccess.providername.com or something as simply as proxy. Contact your service provider for this information. This APN will be needed when configuring the DCM-100B (Chapter-5). Service providers may have several different gateways to choose from, depending upon the type of service required. Web phones (cellular phones that support Internet access) are generally assigned to a gateway that only connects to WAP services (wireless application protocol). The DCM-100B requires full Internet access because the data collection software could be running on any server located anywhere in the world. Full access gateways are usually assigned to customers who will be connecting a wireless modem to a personal computer. 4-1

44 Another parameter that will be needed is the packet service connection command. In most cases the command will be ATD*99# but you may want to check with your service provider Establishing Cellular Service for GSM CSD A cellular account must be activated with the local service provider prior to placing a DCM-100B into service. Many GSM service providers offer some sort of data support, but their marketing focus may be on Internet connectivity or short-message services ( SMS, used to send text messages to and from cellular phones). This does not necessarily mean that they support all forms of data transfers. The service provider must support asynchronous circuit-switched data (CSD) exchange at 4800 or 9600 baud. The baud rate must match the baud rate of the central computer s modem. Sometimes this capability may be included as part of a standard voice package, or it may be an add-on feature at extra cost. One consideration when ordering service is the frequency of calls to and from the DCM- 100B. Each service provider offers different packages that may include a fixed number of minutes per month for a fixed price. However, when this number is exceeded, the cost per each additional minute can be very high. There are also variations in the way minutes are measured. For example, a call lasting 1 minute 10 seconds may be considered to be a 2-minute call by some providers. It might be possible to purchase less expensive packages that have additional weekend or evening minutes, and then schedule the field device to call in at those times. Some plans may offer the 1 st minute free. This might be advantageous for short calls. Another consideration when ordering service is the location of the DCM-100B with respect to the service provider s network. It is best to describe where the units will be located and where they will be calling, otherwise you could be charged roaming or long-distance fees. Some providers offer free long distance or no roaming charges as part of their basic plans. The final consideration is the direction of the calls. If the DCM-100B is to originate calls, then the service must support mobile-originate service. If the unit is to receive calls, then mobile-terminate service is required. The service provider will need the following information: Type of cellular service desired, which is circuit-switched data (CSD). Data mode is to support 4800 or 9600-baud operation. This rate must match the speed of central computer s modem. Mobile-originate and/or mobile-terminate service. Number of minutes per month. Location of the DCM-100B and the location of central computer (to determine if roaming or long distance charges apply). The service provider may need to know the IMEI number printed on the radio. 4-2

45 4.1.4 SIM Card Installation After the account has been established, the cellular service provider will provide a small memory card known as a SIM card (Subscriber Identity Module). Figure 4-1 illustrates the appearance of a SIM card. Figure 4-1 SIM Card Profile Motorola cellular modules have a plastic holder incorporated on the board that is ready to accept a SIM card. Care must be exercised to ensure that the electrical contacts of the SIM card will mate properly with the electrical contacts on the radio module. Figure 4-2 illustrates the location of the holder. Note the location of the notched corner on the SIM card. WARNING Disconnect all power sources before installing the SIM card! 4-3

46 Figure 4-2 SIM Card Installation Requesting a Voice Phone Number or SMS Service As mentioned earlier some cellular service providers may not support the ability to place a data call to the DCM-100B in CSD mode. This is called mobile-terminate service. If purchasing packet service it is important to know that the DCM-100B can only originate an Internet connection. It cannot be contacted via the Internet because mobile devices to not have permanent Internet addresses. Yet there may be times when it is desirable to communicate immediately with the field device rather than wait for it to call in. To overcome these limitations the DCM-100B supports the ability to be paged. When paged the DCM-100B will immediately call back to the central computer. There are two ways to page, and these are described in Chapter-8. If the cellular account has been assigned a voice or data number then the unit can be called using this number. Otherwise most cellular providers can include SMS (short message service) as part of the package. This allows the DCM-100B to be paged with a text message. If you are going to use paging then the phone number or SMS address will have to be manually entered into the InvisiConnect or DC-2000 software or into an address list. This can be quite tedious if you are going to be installing hundreds of units. The 4-4

47 cellular service provider can program the voice phone number into the SIM card, and the DCM-100B can read this number and report it to InvisiConnect. Even if you are using SMS, the address of the unit is often created using the voice or data phone number as part of the address, such as InvisiConnect can automatically construct the entire SMS address for you. See Chapter-6. Most SIM cards have spaces to hold three phone numbers. Ask your cellular provider to program the voice number into the first location. If they support mobile-terminate CSD service then have them program the data number into the first location. If you are going to use SMS, ask what the address will be, and have them program the base number into the first SIM location. 4.2 CDMA Service CDMA Overview CDMA is an abbreviation for Code Division Multiple Access communications. CDMA technology was originally developed for military applications but was eventually commercialized. This communications standard is widely used in North America and in some parts of Asia and South America. Rather than dividing calls into time slots like GSM, CDMA allows all users to transmit at the same time. Each call is accompanied by a unique digital code that allows it to be differentiated from the rest. As an analogy suppose you are in a crowded room and many conversations are taking place at the same time. Your brain is able to distinguish the conversation you are having with your friend because it is able to focus on your friend s voice characteristics. As the room grows more crowded each person must talk louder and the size of the conversation zone grows smaller. You may have to move closer to your friend to keep the conversation going. Thus the number of conversations is limited by the overall interference and noise in the room Establishing Cellular Service for CDMA 1XRTT Packet Service A cellular account must be activated with a cellular service provider prior to placing a DCM-100B into service. Some CDMA service providers may not offer all forms of data transfer. Single carrier, radio transmission technology (1X or 1XRTT) packet service may have to be added to a standard voice plan, or may be a stand-alone service. Packet service packages are generally priced by the number of bytes to be transferred rather than by the minute. Typically the smallest available package will be 1 megabyte (1 Mb) per month. The amount of data that the DCM-100B will produce depends upon what sort of data is requested from the field device. The amount of information exchanged on each call may range from several hundred bytes to 10 s of thousands of bytes. It may be necessary to test the system for several months and then adjust the cellular account for the best cost based on your needs. The DCM-100B requires full Internet access because the data collection software could be running on any server 4-5

48 located anywhere in the world. Full access is usually assigned to customers who will be connecting a wireless modem to a personal computer. One parameter that will be needed is the packet service connection command. In most cases the command will be ATD#777 but you may want to check with your service provider Establishing Cellular Service for CDMA CSD A cellular account must be activated with the local service provider prior to placing a DCM-100B into service. Many CDMA service providers offer some sort of data support, but their marketing focus may be on Internet connectivity or short-message services ( SMS, used to send text messages to and from cellular phones). This does not necessarily mean that they support all forms of data transfers. The service provider must support asynchronous circuit-switched data (CSD) exchange at the baud rate of the central computer s modem. Sometimes this capability may be included as part of a standard voice package, or it may be an add-on feature at extra cost. One consideration when ordering service is the frequency of calls to and from the DCM- 100B. Each service provider offers different packages that may include a fixed number of minutes per month for a fixed price. However, when this number is exceeded, the cost per each additional minute can be very high. There are also variations in the way minutes are measured. For example, a call lasting 1 minute 10 seconds may be considered to be a 2-minute call by some providers. It might be possible to purchase less expensive packages that have additional weekend or evening minutes, and then schedule the field device to call in at those times. Some plans may offer the 1 st minute free. This might be advantageous for short calls. Another consideration when ordering service is the location of the DCM-100B with respect to the service provider s network. It is best to describe where the units will be located and where they will be calling, otherwise you could be charged roaming or long-distance fees. Some providers offer free long distance or no roaming charges as part of their basic plans. The final consideration is the direction of the calls. If the DCM-100B is to originate calls, then the service must support mobile-originate service. If the unit is to receive calls, then mobile-terminate service is required. The service provider will need the following information: Type of cellular service desired, which is circuit-switched data (CSD). Data rate. This rate must match the speed of central computer s modem. Mobile-originate and/or mobile-terminate service. Number of minutes per month. Location of the DCM-100B and the location of central computer (to determine if roaming or long distance charges apply). The service provider may need to know the IMEI number printed on the radio. 4-6

49 4.2.4 Requesting a Voice Phone Number or SMS Service As mentioned earlier some cellular service providers may not support the ability to place a data call to the DCM-100B in CSD mode. This is called mobile-terminate service. If purchasing packet service it is important to know that the DCM-100B can only originate an Internet connection. It cannot be contacted via the Internet because mobile devices to not have permanent Internet addresses. Yet there may be times when it is desirable to communicate immediately with the field device rather than wait for it to call in. To overcome these limitations the DCM-100B supports the ability to be paged. When paged the DCM-100B will immediately call back to the central computer. There are two ways to page, and these are described in Chapter-8. If the cellular account has been assigned a voice or data number then the unit can be called using this number. Otherwise most cellular providers can include SMS (short message service) as part of the package. This allows the DCM-100B to be paged with a text message Over-the-Air Activation CDMA technology does not support the use of a SIM card (Subscriber Identity Module) to hold and transport account information. Therefore the account information must be downloaded into the cellular module s own memory. This is usually accomplished by dialing a special phone number to request that the radio be activated over-the-air (OTA). The phone number is specific to the service provider and must be programmed into the DCM-100B using the MP32 configuration software (Chapter-5). The DCM-100B will read the phone number that is assigned to the radio. If the phone number contains all zeros then the activation number is dialed and over-the-air activation is attempted. 4-7

50 4-8

51 5 CONFIGURATION USING METRETEK PROGRAMMER 5.1 Metretek Programmer Cable Before placing a DCM-100 into service, it is necessary to setup certain configuration parameters. Setting up the configuration requires a computer, Metretek programmer (MP32) software and a special programming cable. These items are listed below: 80x86 or Pentium-based personal computer with an available 9-pin serial port (COM1, COM2). Minimum operating system is Windows 98. Windows -based Metretek Programmer software, MP32, available under Metretek P/N: The MP32 software must be version or later. PC-to-Remote Interface cable, Metretek P/N B-001. An illustration of the cable assembly was provided in Chapter-2, Figure 2-1. The DCM-100 stores configuration information in its on-board EEPROM memory. Certain parameters are unique to each DCM-100, such as a phone number to call, cellular service details, etc. These parameters can be programmed prior to, during, or after installation of the device in the field, although it is normally most convenient to setup and test the configuration prior to installation. Connection Process 1) Attach the 9-pin D-sub end of the PC-to-Remote Interface cable to an available serial communications port on the computer, such as COM1. 2) Attach the opposite end of the interface cable to the 4-position connector (J8) on the SNI-III board. The connector is keyed and can only insert in one direction. 5-1

52 5.2 MP32 Software Startup MP32 can operate as a stand-alone program or can work in conjunction with Metretek s DC-2000 data collection software (DC-2000 is used when the interfacing to a series corrector). When MP32 is started it will require a user name and password. If DC-2000 is present then the password must match one of the passwords from DC s list of authorized users. If this is a standalone application then leave the password blank. Figure 5-1 MP32 Login Screen After login a window will appear to allow you to select the type of Metretek device to program (Figure 5-2). Prior to selecting the device, select the Communication Configuration button. In the next window (Figure 5-3) select the Cable Comm Port as the default, and make sure that the selected port matches the port that the cable is plugged into on the computer, such as COM1, COM2, etc. Then select the OK button. 5-2

53 Figure 5-2 MP32 Start-Up Screen Figure 5-3 Communication Port Configuration Screen 5-3

54 5.3 Main Configuration Screen The original MP32 screen will now reappear (Figure 5-2). Select the DCM-100 button to start the configuration process. Figure 5-4 Main Configuration Screen A configuration can be saved for future use by using the FILE pull-down menu in the upper left-hand corner of the screen. A previously saved configuration can be opened in the same manner. This is useful when several units are to be programmed with similar information, such as the same destination IP address. To start a session either OPEN a previously saved configuration or perform a READ operation with the cable installed and the unit powered up. If the DCM-100 is busy it may take up to 20 seconds to respond, so please be patient. The status of the operation is displayed on the bottom of the screen. The CANCEL button will terminate the session in the event there is no response. 5-4

55 5.3.1 Remote Unit ID Each DCM-100 must have a unique ID number. Legal six-digit values are FFFFFF (hexadecimal notation). Sequential numbering is not required, nor is it necessary to use any of the hexadecimal digits A, B, C, D, E, or F. The DCM-100 has a special mode that allows it to initiate calls to the central computer on a regular basis, regardless of the field device s own call-in schedule. A portion of the RUID, along with several other parameters, is used to formulate the call-in schedule. See Chapter-8 for more information Destination If the DCM-100 is allowed to originate a data call to another modem (CSD mode), then it will need the phone number of the modem. Select the Phone Number button and enter up to 32 numeric digits, including the # and * symbols. As with cellular phones, it is usually necessary to enter the entire phone number, including area code, even if the call is local. For example, in the U.S., a call to within area code 987 may have to be entered as If the DCM-100 is to communicate via the Internet then it will need the IP address and port number of the data collection server. Your computer system s administrator usually assigns these values. Select the IP Address button. Then enter the address of the server expressed in dotted decimal format, such as The data collection server is assigned a default port number of This value is displayed on the MP32 screen for reference only. This is the port number that will need to be assigned on the server. If the port number needs to be changed hold down the CTRL key on the keyboard, point to the port number box and double click the pointing device (ie mouse). Then enter a new port number Originate Calls Check this box if the DCM-100 is allowed to originate CSD calls or Internet connections Respond to Voice Calls Check this box if the DCM-100 is allowed to answer CSD calls, or is allowed to be paged using its voice phone number. See Chapter-8 for more information about paging. Be aware that battery life will be greatly reduced if this option is selected because the radio must remain powered-up in order to detect incoming calls Respond to SMS Check this box if the DCM-100 is allowed to be paged via SMS (short message service). See Chapter-8 for more information about paging. Be aware that battery life will be greatly reduced if this option is selected because the radio must remain powered-up in order to detect messages Maintain Internet Connection When the DCM-100 originates an Internet connection, it must request access to the cellular provider s packet service, then access to the Internet and finally access to the destination server. All of this negotiation takes a certain amount of time. To reduce this time the DCM-100 can maintain access to the Internet at all times and only needs to request access to the destination server, which only takes a few seconds. This is often referred to as an always on connection. 5-5

56 NOTE: To use this feature you must also check the Originate Calls checkbox. When maintaining an Internet connection it is not possible to answer incoming phone calls or SMS pages, so those selection boxes are disabled on the screen. Be aware that battery life will be greatly reduced if this option is selected because the radio must remain powered-up in order to maintain the Internet connection Dual Port This selection allows two field devices to be connected to the DCM-100 using the optional dual-port multiplexer board described in Chapter-2. If the Dual Port box is checked then two other selections are enabled. The first selection is only used in CSD mode and allows the DCM-100 to wait a certain number of seconds to receive a port select command from the central computer, which will be discussed in Chapter-8. If no command is received within this time frame, the DCM-100 will select a port based on the second selection. The second selection is used in both CSD and Internet mode. The choices are Port-1, Port-2, Alternate or None. This is the port that will be selected for an incoming CSD call or if the unit is paged to call back to the central computer. If Alternate is selected then the port selection will alternate with every call. The first call will go to Port-1, the second call to Port-2, the third to Port-1 and so on. See Chapter-8 for more information Firmware Version The firmware version is a value that is updated on the screen whenever a Read operation is performed. This is not a parameter that can be modified by the user Primary Call Retry Rate If the DCM-100 is programmed to originate a call, and the call is unsuccessful for any reason, it will try again at a later time. The DCM-100 can be programmed to wait from 1 to 15 minutes between each attempt. The DCM-100 has a special mode that allows it to initiate calls to the central computer on a regular basis, regardless of the field device s own call-in schedule. The Primary Call Retry Rate, along with several other parameters, is used to formulate the call-in schedule. See Chapter-8 for more information Primary Call Retry Count This is the number of times (15 maximum) the DCM-100 will try to repeat a call at the Primary Call Retry Rate, discussed previously. After this, calls will be attempted at the Secondary Call Retry Rate, discussed next. The DCM-100 has a special mode that allows it to initiate calls to the central computer on a regular basis, regardless of the field device s own call-in schedule. The Primary Call Retry Count, along with several other parameters, is used to formulate the call-in schedule. See Chapter-8 for more information Secondary Call Retry Interval After the Primary Call Retry Count has expired, the Secondary Call Retry Interval defines the time between each additional attempt, in 1-hour increments up to a maximum of 15 hours. There is no limit to the number of times the DCM-100 will attempt 5-6

57 to place a call at this rate. Once a call is successful, the DCM-100 will return to using the primary retry rate and count. The DCM-100 has a special mode that allows it to initiate calls to the central computer on a regular basis, regardless of the field device s own call-in schedule. The Secondary Call Retry Interval, along with several other parameters, is used to formulate the call-in schedule. See Chapter-8 for more information. NOTE TO 6000-SERIES CORRECTOR USERS A 6000-series corrector also has its own programmable call retry strategy. It will generally retry a call if the data received was in error or an improper command was received. The DCM-100 will only retry a call due to cellular communications problems, such as a lost connection, an invalid packet or a busy signal. It may be necessary to adjust both units retry strategies to obtain the best performance Alarm Input 1 & 2 Back in Section 2.8 there was a discussion about how alarm switches can be wired to the DCM-100. The DCM-100 can react to Form-A switch closures on Input #1 and #2 by placing an immediate call to the central computer if it is configured to originate calls. Or it can simply report the occurrence of these alarms on the next scheduled call. If using InvisiConnect these conditions will be reported to the user on the screen as well as logged into a disk file. They are not reported if using a 6000-series corrector and the DC-2000 data collection software, but a call will be placed nonetheless. In CSD mode a special mode is discussed in detail in Chapter-8. In this mode the DCM- 100 can send readable (ASCII) text strings to the computer to describe the current status, such as * Alarm-1 *, * TAMPER ALARM *, etc., along with the unit s remote unit I.D. If Input #1 and/or #2 is to be used to monitor an alarm switch, select On on the configuration screen. If the DCM-100 is allowed to originate a call when an Alarm #1 condition occurs, the primary phone number or Internet address will be used. This is shown to the right for reference and is a copy of the primary Destination number. A different phone number or Internet address can be specified for Alarm #2. For instance, the DCM-100 could be programmed to call into InvisiConnect for an Alarm #1 condition and could call a pager or cell phone for an Alarm #2 condition. 5-7

58 5.4 Serial Port-1 Screen Select the SERIAL PORT 1 tab to continue the configuration. Figure 5-5 Screen Image with Serial Port 1 Tab Selected Port Select ID The Port Select ID for Serial Port #1 defaults to the remote unit ID (RUID) that was assigned to the DCM-100. It is shown on the SERIAL PORT 1 tab for reference and cannot be changed Max BPS This value must match the baud rate of the field device. If using a 6000-Series corrector set the rate for 9600 baud. Important Note: If using circuit-switched data (CSD) service, the MAX BPS setting also sets the CSD baud rate. This is often referred to as bearer service. Many cellular service providers no longer support CSD baud rates below The radio module used in the DCM-100 does not support baud rates below If the destination modem is a Metretek MODSMOD modem bank, you will need at least one 9600 baud modem card installed. 5-8

59 5.4.3 Flow Control Chapter-8 has information about flow control. If using a 6000-Series corrector, select Custom #1. In CSD mode each byte of data from the field device is immediately passed on to the central computer, and visa versa. In this case flow control is generally not needed and NONE can be selected. In packet mode the data from the field device is assembled into a packet, then sent on to the central computer. The packet cannot be larger than 1400 bytes and each packet s arrival at the central computer must be verified before another can be sent. Due to latency in the cellular networks and on the Internet each exchange may take several seconds to complete. During this time it is necessary to stop the field device from sending any more information. This can be done using either Hardware or Xon/Xoff flow control. Chapter-8 will help you decide which technique to use Wait ms before sending packets The setting has no effect in CSD mode. In packet mode the data from the field device is assembled into packets and sent on to the central computer. Therefore the DCM-100 must have a way to determine when the field device s message is complete and ready to send to the computer. Some field devices may end a message with a particular character like a carriage return or line feed. However for other devices these two characters may be meaningful data. Therefore searching for a particular terminating character may not work in all cases. The DCM-100 determines when a message is complete when there have been no characters received from the field device for a certain period of time. This value can range from 1 to milliseconds and may have to be determined experimentally. A value that is too low may cause a message to be sent is several packets. A break in a message may confuse the field device and could cause it to abort the session or retry too often. Also, each packet contains the device s message along with some overhead information used for routing and error checking. Breaking a larger message down into several packets means more overhead and could affect the cost of the cellular service. Remember, the cost of packet service is based on the number of bytes exchanged in a month. Choosing a value that is too high may cause the application program running on the central computer to abort or retry too often because it did not receive a response within an acceptable period of time. See Chapter-8 for more information. For 6000-Series corrector users (Custom #1 selected for the Flow Control setting), this field defaults to 50 milliseconds Maximum Packet Size The setting has no effect in CSD mode. In packet mode the data from the field device is assembled into packets and sent on to the central computer. The maximum packet size is 1400 bytes. Depending upon cellular network congestion and the quality of the radio connection, it may help to reduce the packet size. The larger the packet, the more chance there is for errors. Several smaller packets may have a better chance of arriving 5-9

60 intact than a single large one. As each packet arrives at the central computer, it is checked for errors. If a packet arrives with errors, the computer will request retransmissions until it arrives intact or until a maximum number of retries have occurred. This can introduce significant delays and may increase the cost of the cellular service. Remember, the cost of packet service is based on the number of bytes exchanged in a month. Excessive retries may cause your maximum plan limit to be exceeded. If you notice excessive retries, or if the connection between the field device and the central computer terminates early or often, this may be the cause. InvisiConnect s packet size can also be changed and does not have to match the size set for the DCM For 6000-Series corrector users (Custom #1 selected for the Flow Control setting), this field defaults to Data Bits This value must match the number of data bits used by the field device. For Series corrector users (Custom #1 selected for the Flow Control setting), this field defaults to Parity Type This value must match the type of parity used by the field device For 6000-Series corrector users (Custom #1 selected for the Flow Control setting), this field defaults to NONE Stop Bits This value must match the number of stop bits used by the field device. For Series corrector users (Custom #1 selected for the Flow Control setting), this field defaults to Always Send Connect Message In Chapter-8 there is a discussion about how the field device can request a call or answer an incoming call by issuing specific AT commands such as ATD (dial) or ATA (answer). When the connection with the central computer has been established the DCM-100 will send a CONNECT message to the field device. The DCM-100 can also place a call on its own in response to an alarm condition or some other event. In these situations the DCM-100 would not normally send a CONNECT message to the field device. However, some field devices may require a CONNECT message before allowing further communications. By checking the Always Send Connect Message box, the DCM-100 will always send a CONNECT message every time it connects with the central computer. 5-10

61 Always RING Port In some applications the modem may be programmed to automatically answer incoming calls. After the call is answered and a connection is established with the central computer a CONNECT message is usually sent to the field device. In other applications the field device might control if and when incoming calls will be answered. The modem will send a number of RING messages to the field device and wait for the field device to respond with an answer ( ATA ) command. If this mode is required, check the Always RING Port checkbox. The DCM-100 will send up to three RING messages to the field device. If an ATA is received the DCM-100 will respond with a CONNECT message. If no response is received the DCM-100 will send a CONNECT message only if the Always Send Connect Message box has been checked. See Chapter-8 for more information Use Non-verbose Result Codes In Chapter-8 there is a discussion about AT-compatible modems and the types of messages that they can produce. A verbose message is usually a readable text string such as CONNECT or RING. A terse, numeric, or non-verbose message typically consists of one or two numeric digits, such as 2. The DCM-100 defaults to verbose messages, but the field device can change this by issuing an ATV command. However, some field devices may simply expect non-verbose messages and will not issue any additional commands to make this happen. In this case check the Use Nonverbose Result Codes box. Chapter-8 has a table that lists the most common verbose and non-verbose responses Override CONNECT Message Usually the field device requires some sort of notification when a connection has been established with the central computer. Often this message will be CONNECT xxxx, where xxxx indicates the baud rate, such as CONNECT The DCM-100 defaults to this format, but the field device can change this to a simple CONNECT message by issuing an ATX command. However, some field devices may simply expect a simple CONNECT message and will not issue any additional commands to make this happen. In this case check the Override CONNECT Message box. You must specify the exact message in the Connect Message window. This includes non-readable (control) characters. Non-verbose responses are often one to two ASCII numbers followed by a carriage return character. Verbose messages are normally preceded and followed by a carriage return and line feed combination. Use the Enter key on your keyboard to insert a carriage return and line feed combination. To insert a single line feed character press and hold the ALT key while on the keyboard s numeric keypad enter the digits Then release the ALT key. To insert a single carriage return character press and hold the ALT key while on the keyboard s numeric keypad enter the digits Then release the ALT key. In either case you will not actually see the characters in the window, but you may see the cursor move to the next line. 5-11

62 5.5 Serial Port-2 Screen If you have selected Dual Port mode (discussed earlier), then select the SERIAL PORT 2 tab to continue the configuration. All settings are identical to those for Serial Port 1 except for the Port Select ID. You must assign a unique ID number to the device connected to Port-2. This will allow the central computer to distinguish between the two devices. Legal six-digit values are FFFFFF (hexadecimal notation). Sequential numbering is not required, nor is it necessary to use any of the hexadecimal digits A, B, C, D, E, or F. 5.6 Cellular Settings Screen Select the Cellular Settings tab to continue the configuration. Figure 5-6 Screen Image with the Cellular Settings Tab Selected Service Type One of two options can be selected, GSM or CDMA. Each type requires a different version of the SNI-III board. 5-12

63 5.6.2 PIN Number GSM cellular radios require a memory card called a SIM card (Subscriber Identity Module). This is issued to the cellular customer when the cellular service is purchased. A SIM holds information about the account so that certain services are made available to the customer such as Internet access. A SIM card can be moved to a different phone or radio, and the account information moves with it. Though convenient, this may encourage someone to steal the SIM card, insert it into his or her own cellular phone and make hundreds of hours of calls that will be billed to the owner of the card. A personal identification number (PIN) as an extra security measure to prevent unauthorized use of a SIM card. The PIN number can range from 1 to 8 numeric digits long and can be assigned by the cellular service provider when the card is activated. If a PIN number is not used, leave the PIN Number field blank. Do not fill it with 0 s, because a 0 is a valid PIN digit. CDMA does not support the use of a PIN number Frequency Depending upon the service provider chosen and the region of the world in which the DCM-100 is located, there will be a specific frequency band used for the cellular service. These are generally 1900 MHz in North America, and 900 or 1800 MHz elsewhere GPRS Access Point Name (GSM only) If the DCM-100 will be making an Internet connection (GSM GPRS mode), the cellular service provider will need to provide an Internet APN (access point name). In order to connect to the Internet, the provider has its own computer equipment called a gateway server. The server will usually have an APN in the form of a domain name, such as myserviceprovider.com or a generic name such as proxy. Contact your service provider for this information. Service providers may have several different gateways to choose from, depending upon the type of service required. Web phones (cellular phones that support Internet access) are generally assigned to a gateway that only connects to WAP services (wireless application protocol). The DCM-100 requires full Internet access because the data collection software could be running on any server located anywhere in the world. Full access gateways are usually assigned to customers who will be connecting a wireless modem to a personal computer Packet Service Connection Command This command is issued to the cellular radio to request a packet (Internet) connection. For most GSM cellular service providers the phrase ATD*99# will work, and this is the default setting for the DCM-100 in GSM mode. For most CDMA service providers the phrase ATD#777 will work, and this is the default setting for the DCM-100 in CDMA mode. If you are having problems connecting, this could be the problem. Contact your service provider for more information OTA Programming Number (CDMA only) Unlike GSM radios, CDMA radios do not use SIM (Subscriber Identity Module) cards to hold account information. After purchasing CDMA service the radio must dial a special 5-13

64 phone number to be activated and to have account information downloaded into the phone s memory. This phone number is specific to the carrier and must be entered into the OTA Programming Number slot in MP32. OTA means over-the-air PAP User Name and Password As an added security measure some cellular service providers use Password Authentication Protocol, or PAP. In order to gain access to their Internet service you must present a user name and a password that was assigned when the cellular service was purchased. The user name or password can be any combination of printable ASCII characters, including spaces, such as Joe Smith or The total number of characters for both the user name and password cannot exceed 98 characters. The password is hidden on this screen for added security. You must enter the password twice to verify that it was entered correctly. PAP is supported in units with firmware version V4.8 and above. NOTE If PAP is not required then both the user name and password fields must be blank. 5.7 Programming the DCM-100 Once the parameters have been entered (or read in from a previously-saved configuration file), select the PROGRAM button to start programming the DCM-100. Status messages will appear in the lower left-hand corner of the screen. If the DCM-100 is busy with radio operations, it could take up to 30 seconds to respond to the program command. If communications cannot be established within several minutes, check your cable and serial port, and try again. When programming has completed, unplug the 4-pin connector of the serial cable from the J8 connector on the SNI-III board. The DCM-100 is now ready to be put into service. 5-14

65 6 CONFIGURATION OF INVISICONNECT NOTE If the field device is a 6000-Series Corrector, proceed to Chapter Introduction Your existing remote system probably consists of these basic components: a) One or more remote devices that probably contain modems that are connected to a standard wired telephone system. In some cases the modem s analog signals may be transmitted over analog cellular networks or private wireless radio systems. In special cases CDPD modems might be used to exchange digital information over analog cellular networks. b) A computer running a custom-written or off-the-shelf application program that can call or be called by the remote field devices. This program may also process the data received from or sent to the devices. c) One or more modems connected to the computer to exchange information with the remote devices. Again, these may be wired or wireless arrangements. InvisiConnect and the DCM-100B are intended to replace the communications link between the computer and the field devices, offering the cost advantages and new features of digital cellular technology. The DCM-100B replaces the field device s modem while InvisiConnect replaces the modem on the computer. In most cases there are few if any changes required to your original application program or the field devices, both of which probably represent a majority of your capital investment. This system should offer cost savings due to lower monthly communications charges and lower initial installation costs. Finally, with the eventual discontinuation of analog cellular and CDPD service, this may be the best way to avoid a total system replacement. Generally most modems connect to the computer using one or more of the computer s serial communications (COM) ports. InvisiConnect emulates one or many physical COM ports and will appear to your application program as though actual COM ports are present and that modems are attached to those ports. Each application may expect slightly different responses from the modem or the port. InvisiConnect can be configured to accommodate these nuances. InvisiConnect also manages the Internet communications with the DCM-100B and can handle exchanges with many remote devices at once. 6-1

66 6.2 InvisiConnect License Agreements Each running copy of the InvisiConnect server requires a license, and each emulated COM port requires a license. Contact Metretek for terms and agreements. You can add COM port licenses at any time. 6.3 Flow Control (Handshaking) There may be situations in which one device is sending data at a volume that exceeds the receiving device s capacity to store and process it. There are several methods commonly used to control the flow of data, generally called handshaking. Hardware handshaking uses additional signals on the hardware interface to stop and start the flow, whereas Xon/Xoff (also called software handshaking ) uses two ASCII characters to stop and start the flow. InvisiConnect supports both methods. If your application program is expecting to use hardware or software handshaking, then InvisiConnect must be configured to do the same. There is also a setting for no handshaking at all. 6.4 InvisiConnect Modem Emulation Details Most analog modems respond a set of commands called AT commands. This was originally devised by one modem manufacturer and was eventually adopted by most others. An AT-compatible modem is expected to respond in a consistent manner to these commands. Unfortunately this is not always the case and adjustments are often needed when using different types of modems. Your application program may be expecting a physical modem to be present and is expecting certain responses to its commands. AT commands always start with the characters AT followed by other characters that define specific operations. Upon completion of a command the AT modem sends back a response in one of two formats, either terse or verbose. Terse messages are often one to two ASCII numbers followed by a carriage return (<cr>) character. Verbose messages are readable ASCII messages preceded and followed by a carriage return and line feed combination (<cr><lf>). For example, when an incoming call is detected the verbose message will be <cr><lf>ring<cr><lf> whereas the terse version is simply 2<cr>. InvisiConnect can be configured to generate either type. This is discussed in more detail later. For incoming calls from the remote device a typical modem will produce a RING message each time the phone rings. Some application programs will detect this and will instruct the modem to answer the call using the ATA (answer) command. Other programs may expect the modem to answer the call itself. InvisiConnect can be configured for either mode. This is discussed in more detail later. After placing or answering a call the modems on each end of the line will attempt to establish a reliable connection. The modems will then produce a CONNECT message to let the system know that they are online with each other. Some modems include the baud rate in the message, such as CONNECT InvisiConnect can be configured for either type of response. This is discussed in more detail later. 6-2

67 Your program may issue other commands that were important to the original modem but not to InvisiConnect. In these cases InvisiConnect will return a standard response such as OK to these commands. Other commands are meaningful and InvisiConnect will act upon them ATV (response type) Command The ATV command specifies the type of response to be sent back by InvisiConnect, either terse or verbose. These commands will override the default setting that is defined in the COM Port Configuration screen, to be discussed shortly. ATV, ATV0: This instructs InvisiConnect to return terse result codes starting with this command. ATV1: This instructs InvisiConnect to return verbose result codes starting with this command ATE (echo) Command An AT modem can be instructed to immediately return every character it receives from the application program. This is called echoing. The ATE command controls this function. The default is echo on. ATE, ATE0: This instructs InvisiConnect to disable echoing starting with the next command. ATE1: This instructs InvisiConnect to enable echoing starting with the next command ATZ (default settings) Command An AT modem can be instructed to return to a set of default settings with this command. InvisiConnect will default to echo on and either verbose or terse responses, depending upon the setting in the COM Port Configuration screen, to be discussed shortly ATH (hangup) Command ATH, ATH0: This instructs InvisiConnect to terminate the connection with the DCM- 100B and field device. The normal response to this is NO CARRIER ATA (answer) Command ATA: This instructs InvisiConnect to answer an incoming call and establish a connection with the field device. The normal response is a CONNECT message if a connection is established or NO CARRIER if one could not be established. The exact content of the CONNECT message is defined in the COM Port Configuration screen, to be discussed shortly. 6-3

68 6.4.6 ATD (dial) Command ATDxxxx, ATDPxxxx, ATDTxxxx: For traditional modems these commands would instruct the modem to go off hook, dial the phone number of the remote device and establish a connection. The xxxx portion of this command is the phone number to dial. Every device connected to the Internet has an Internet protocol ( IP ) address. Devices with static IP addresses are typically servers that are always on and always ready to accept a request for communications. Their addresses are well known. Other devices, typically called clients, are assigned temporary or dynamic addresses that are only valid during the connection. At the present time a mobile device, including the DCM- 100B, is considered a client and therefore can only originate a request for an Internet connection. Therefore it cannot be contacted directly via the Internet. However the DCM-100B can be paged by sending it an SMS message. SMS (short message service) was developed to allow short text messages to be sent to cellular phones. When the DCM-100B receives an SMS message it will immediately call back to the primary IP address that has been programmed into the unit. There is also a feature that allows the DCM-100B to call back to an IP address that is different than the one that is programmed into the DCM-100B. See Chapters-4, 5 and 8 for more information about paging and SMS. The ATD command instructs InvisiConnect to page the DCM-100B and wait for the unit to call back. The xxxx portion of the command is used to construct the SMS address of the DCM-100B. This will be discussed shortly. When the DCM-100B calls back InvisiConnect will return a CONNECT message to the application program. If the unit does not call back within a reasonable amount of time the application program will probably terminate the call itself. As discussed in Chapter-2 two field devices can be connected to one DCM-100B using an optional dual-port multiplexer board. InvisiConnect has a feature that allows you to select a particular port at any time, and this will be discussed later in this chapter. An alternate method for port selection involves the use of a special sequence of characters in the phone number string of the ATD command. #*#1 will select Port-1 and #*#2 will select Port-2. This special sequence must be the final four characters of the phone number string. For example the command ATD #*#2 will use to construct the SMS address. When the DCM- 100B calls in InvisiConnect will instruct the unit to select Port-2 once the connection is made (escape) Command Once InvisiConnect has established a connection between the field device and the application program it will no longer respond to AT commands. However AT modems are always looking for an escape sequence, which is +++ followed by 1 second of quiet time. This will return InvisiConnect to AT mode and it will respond with an OK message. At this point other AT commands can be issued to InvisiConnect. 6-4

69 6.4.8 ATO (online) Command Once InvisiConnect has established a connection between the field device and the application program it will no longer respond to AT commands unless the escape sequence is issued ( +++ ). Assuming that the DCM-100B is still connected, InvisiConnect will reestablish the connection if issued an ATO command All Other AT Commands InvisiConnect will respond to all other AT commands with an OK response AT Command Chaining AT commands can be grouped together into one string. For example, the command ATE0V1 commands InvisiConnect to turn off echoing and return verbose responses. However, ATA, ATH or ATD commands should be sent separately or should be the last command in a chain Normal Responses to AT Commands Here is a summary of InvisiConnect s responses to AT commands: Terse Response Verbose Response DESCRIPTION 0 OK Accepted, no error 1 CONNECT Connected with remote modem 2 RING Incoming call 3 NO CARRIER Connection with remote modem is lost 4 ERROR Unrecognized command or value The exact content of the CONNECT message is user-defined on the COM Port Configuration screen. Table 6-1 Normal Responses to AT commands 6-5

70 6.5 InvisiConnect Configuration InvisiConnect acts as one or more Internet servers on your computer and thus must be allowed access to the outside world. Most corporate computer systems use firewall technology to prevent unauthorized and potentially damaging access from outside sources. An Internet address must be assigned to InvisiConnect, and a port number must be assigned for each running server. These same numbers must be programmed into each DCM-100B. To minimize potential invasion, InvisiConnect and each DCM-100B exchange private information using a 64-bit data encryption standard. If this exchange fails, InvisiConnect terminates the connection immediately. When InvisiConnect starts the following basic screen will appear. Figure 6-1 InvisiConnect Main Screen External IP Address First, enter the external Internet (IP) address that was assigned to InvisiConnect. This is the same address that was programmed into each DCM-100B. Your computer system s administrator usually assigns this address. 6-6

71 6.5.2 Server Configuration and Control In the Server Configuration and Control section, select the Add button to define a new server or Edit to change one that is already defined. You can also delete an existing server using the Delete button. NOTE A server must be stopped before changing it. Highlight the desired server, then select the Start / Stop button. Or select the StopAll button to halt all servers. If adding or editing a server configuration, the next screen will appear: Figure 6-2 Server Configuration Screen User Application Interface Your application program may be expecting to communicate with a modem connected to one of the computer s serial ports. In this case select Standard AT Modem. Section 6.4 describes how InvisiConnect emulates an AT modem. For other applications select a Direct Serial connection. For instance, suppose your application program displays images taken from a digital camera. The camera s cable connects directly to a serial port on your computer and everything seems to work well. Now you would like the camera to be located across town. The cable would then be connected to the serial port on the DCM-100B, and the imaging program would 6-7

72 communicate with the camera through InvisiConnect using a direct serial connection. In essence the application program still believes that the camera is directly connected to the computer IP Port Number Though there is only one Internet address assigned to InvisiConnect you can have multiple ports assigned and a unique server running for each port. For instance you could have one port for modem applications and another port assigned for applications that communicate directly with a serial port. Or you might want to partition a group of DCM-100Bs to call into a specific port while others call into another port. Your computer system s administrator usually assigns the port numbers. These numbers must match the port numbers that are programmed into each DCM-100B Server Description Each server will be given a generic name, either Direct Serial or Standard AT Modem. You can assign a different label to each server that more clearly defines the application. For instance we ve assigned the label Digital Camera Server in Figure Auto Start Server At Startup If you check this box then the server will start automatically when you launch InvisiConnect. Otherwise use the Start / Stop button to manually start a server Wait ms before sending packets Data to be sent to the field device is assembled into packets and then sent on to the DCM-100B. Therefore InvisiConnect must have a way to determine when a message is complete and ready to send. Some applications may end a message with a particular character like a carriage return or line feed. However for others these two characters may be meaningful data. Therefore searching for a particular terminating character may not work in all cases. InvisiConnect determines when a message is complete when there have been no characters received from the application for a certain period of time. This value can range from 1 to milliseconds and may have to be determined experimentally. Choosing a value that is too low could cause a single message to be sent in several packets. A break in a message may confuse the field device and could cause it to abort the session or retry too often. Also, each packet contains the user s message along with some overhead information used for routing and error checking. Breaking a larger message down into several packets means more overhead and could affect the cost of the cellular service. The cost of packet service is usually based on the number of bytes exchanged in a month. For example suppose the delay is set to 50 milliseconds. A single message of ABCDEFGH is going to be sent to the device. If for some reason there is a 75 ms pause between the E and F then there will be two messages sent to the device; ABCDE and FGH. Due to latency in the cellular network, the second portion of the message may not arrive for 1-2 seconds after the first, which could cause problems for either the field device or the application program. 6-8

73 Choosing a value that is too high may cause the field device or the application to abort a session or retry too often because messages were not exchanged within an acceptable period of time Maximum Packet Size Data to be sent to the field device is assembled into packets and then sent on to the DCM-100B. The maximum packet size is 1375 bytes. Depending upon cellular network congestion and the quality of the radio connection, it may help to reduce the packet size. The larger the packet, the more chance there is for errors. As each packet arrives at the DCM-100B it is checked for errors. If a packet arrives with errors, the DCM-100B will request retransmissions until it arrives intact or until a maximum number of retries have occurred. This can introduce significant delays and may increase the cost of the cellular service. The cost of packet service is usually based on the number of bytes exchanged in a month. Excessive retries may cause your maximum plan limit to be exceeded. If you notice excessive retries, or if the connection between the field device and the central computer terminates early or often, this may be the cause. The DCM-100B s packet size can also be changed and does not have to match the size set for InvisiConnect Use Packet Concatenation If the message being sent to the field device is larger than the maximum packet size, then the message will be delivered in sections. In wireless Internet systems each section can take up to several seconds to arrive at the DCM-100B due to latency in the cellular network and on the Internet. This may be a problem for the field device if it does not accept long breaks within a single message. If the Use Packet Concatenation box is checked then the DCM-100B will save each portion of the message in memory until the entire message is received, then send the entire message to the field device. The DCM-100B has enough room to store about 20,000 bytes. If this limit is reached, the DCM-100B will send what it has to the field device. It will continue to store the next sections and will repeat this process until the message is complete. If using packet concatenation you might need to adjust the packet size for best performance. Suppose the field device sends a message to the application program and expects a response within 10 seconds. The applications program s response is 2000 bytes in length and the maximum packet size is set for 100 bytes. The 2000-byte message will be broken into 20 sections, and each section may take a second to arrive at the DCM-100B. This means the field device will not see the entire response for a full 20 seconds and will time out. Increasing the packet size to 500 will result in only 4 sections and the entire response will be sent to the field device in about 4-5 seconds Close Connection after Minutes.. Once connected if the DCM-100B does not exchange data with InvisiConnect for 1 minute it will automatically close the Internet connection. Some applications may need a longer time. For instance when using a remote digital camera, the application program might only wish to obtain a new image every 3 minutes. But if the DCM-100B does not detect a message to or from the camera within 1 minute, the connection will be terminated. 6-9

74 To extend the time check this box and enter the number of minutes required. In the case of our camera example you would want to set the time for 4 5 minutes. Entering a value of will keep the connection open as long as the cellular network is operating correctly. This is not recommended if the DCM-100B is operating solely from a battery source Latency Compensation One important difference between traditional direct-wired phone service and wireless Internet service is speed. In wired systems data travels very quickly between the computer and the field device. In wireless Internet systems a message can take up to several seconds to arrive at its destination due to latency in the cellular network and on the Internet. The field device or application program may not have been designed to accept large delays in the communication process, and it may not be possible to modify their behavior. Several novel methods have been developed to keep both the field device and the application program satisfied. You can enable any or all of these features to obtain the best performance. Select the Latency Compensation button to access these features. NOTE The use of Latency Compensation may require an in-depth understanding of how the application program and the field device communicate with each other Fast Loop-Back Response Scenario: The application program sends a message to the field device and expects a response back faster than is possible on the cellular network. If a response is not received in time the application reports an error and terminates, or starts the process over and never makes it past this point. Fast Loop-Back Response is a way to make the application think that a response was received in time. Figure 6-3 depicts the setup screen. 6-10

75 Figure 6-3 Fast Loop-Back Response Screen To enable this feature check the Enable Fast Loop-Back box. Select the ADD button for as many different loop-back responses as needed. In Figure 6-3 we ve illustrated a simple exchange in which the application program sends HELLO to the field device and expects a response of GOODBYE back. Both messages end with a carriage return character. Whenever the application program sends the HELLO message, InvisiConnect will immediately send the GOODBYE response back to the application program. If the Transmit Command box is checked the HELLO message is also transmitted to the field device. If the field device responds, the response will be forwarded to the application. All messages are entered in hexadecimal ( hex ) format. See Chapter-11 for a chart to convert ASCII characters to hex. For instance, the phase HELLO is represented as 48 (H), 45 (E), 4C (L), 4C (L) and 4F (O), followed by a carriage return (0D). This can be entered manually or can be pasted in from a text file or spreadsheet. It is not necessary to separate each character with a space but it may make the string more readable. Always enter two digits for each character. For instance the carriage return character must be entered as 0D and not D. You can enter as many characters as needed but you may only see a portion of the string displayed in each box. You can use your cursor keys to make other portions of the string visible. 6-11

76 Later in this chapter will be a discussion about trace files. InvisiConnect can keep a record of every message sent to and received from the field device. This may help to decide which messages the application is having problems with. If the field device s response to a particular message is always the same, but always arrives late, you can copy and paste both the message and response strings from the trace file into the Fast Loop-Back Response screen Block Transmit Scenario: The application program sends a message to the field device and expects a response back faster than is possible on the cellular network. If a response is not received in time the application sends the same message again and perhaps several more times. In the meantime the field device is being flooded with messages and is trying its best to respond. Both sides are out of sync and the session is likely to terminate because of it. Block Transmit is a way to prevent the field device from being overrun with messages. Figure 6-4 depicts the setup screen. Figure 6-4 Block Transmit Screen To enable this feature check the Block Transmit box. Whenever a message is sent from 6-12

77 the application program to the field device, InvisiConnect will block any further messages from the application program until (a) a response has been received from the field device or (b) a certain amount of time has gone by since the message was sent. This time is specified in terms of milliseconds. There may be some messages that you do not wish to block. In Figure 6-4 we ve entered two such messages; HELLO and GOODBYE. Both messages end with a carriage return character. For each new message select the ADD button. All messages are entered in hexadecimal ( hex ) format. See Chapter-11 for a chart to convert ASCII characters to hex. For instance, the phase HELLO is represented as 48 (H), 45 (E), 4C (L), 4C (L) and 4F (O), followed by a carriage return (0D). This can be entered manually or can be pasted in from a text file or spreadsheet. It is not necessary to separate each character with a space but it may make the string more readable. Always enter two digits for each character. For instance the carriage return character must be entered as 0D and not D. You can enter as many characters as needed, but you may only see a portion of the string displayed in each box. You can use your cursor keys to make other portions of the string visible. In this example whenever the application program sends a HELLO or GOODBYE the next message will not be blocked. This is useful if the field device isn t expected to respond to some messages. Later in this chapter will be a discussion about trace files. InvisiConnect can keep a record of every message sent to and received from the field device. This may help to decide which messages the application is having problems with. You can determine how often the application program repeats a message and how long it takes to obtain a response from the field device Tickle Hold-Off Scenario: The application program sends a message to the field device and expects a response back faster than is possible on the cellular network. If a response is not received in time the application reports an error and terminates, or starts the process over and never makes it past this point. However, if an incorrect response is received within the allotted time frame, the application program may ignore it and wait a bit longer for a correct response to arrive. Tickle Hold-Off is a way to make the application think that a response was received in time, although perhaps not a correct response. Figure 6-5 depicts the setup screen. 6-13

78 Figure 6-5 Tickle Hold-Off Screen To enable this feature check the Tickle Hold-Off box. In Figure 6-5 we ve entered one such message of HELLO followed by a carriage return character. For each new message select the ADD button. All messages are entered in hexadecimal ( hex ) format. See Chapter-11 for a chart to convert ASCII characters to hex. For instance, the phase HELLO is represented as 48 (H), 45 (E), 4C (L), 4C (L) and 4F (O), followed by a carriage return (0D). This can be entered manually or can be pasted in from a text file or spreadsheet. It is not necessary to separate each character with a space but it may make the string more readable. Always enter two digits for each character. For instance the carriage return character must be entered as 0D and not D. You can enter as many characters as needed, but you may only see a portion of the string displayed in each box. You can use your cursor keys to make other portions of the string visible. In our example assume the application program is sending HELLO to the field device and is expecting a response of GOODBYE within 2 seconds. Due to network latency the response from the field device will not arrive for 3 seconds. We ve entered a hold-off response of one single carriage return character (0D). After a certain amount of time (which you specify in terms of milliseconds in the DELAY box) InvisiConnect will send the hold-off string to the application program (in this example once every second). The application program rejects the response, resets its timer and continues to look for a good response. InvisiConnect will do this as many times as you specify in the COUNT 6-14

79 box (in this example up to 3 times). When the GOODBYE response finally arrives it will be sent to the application program. Later in this chapter will be a discussion about trace files. InvisiConnect can keep a record of every message sent to and received from the field device. This may help to decide which messages the application is having problems with. You can determine how often the application program requires some sort of response and how long it takes to obtain a response from the field device Force Connect Message Scenario: The application program issues an ATD dial command and expects a CONNECT message back within 30 seconds. Due to network latency the connection time between InvisiConnect and the DCM-100B takes 40 seconds. Therefore the application program times out, reports an error and terminates. The Force Connect Message feature allows a CONNECT message to be returned to the application program prior to the real connection with the field device. The exact form of the CONNECT message is defined by you on the Comm Port Configuration screen. This will be discussed in the next section. If the application program then issues other commands prior to the real connection, InvisiConnect will return a user-defined response to keep the application program from timing out and terminating. Figure 6-6 Force Connect Message Screen 6-15

80 To enable this feature check the Force Connect Message box and enter the time in seconds that the CONNECT message will be returned to the application program. For instance if the application requires a response within 30 seconds you might want to use 25 seconds. Give InvisiConnect and the DCM-100B as much time as possible to make a real connection. Once the CONNECT message is returned to the application program InvisiConnect will continue to establish a real connection with the DCM-100B. In the meantime if the application program issues commands to be sent to the field device, InvisiConnect will return the response that you defined in the lower portion of the screen. It will not actually send any commands to the field device until the real connection is established. In Figure 6-6 we ve entered a response of ASCII 2 followed by a carriage return character. The response is entered in hexadecimal ( hex ) format. See Chapter-11 for a chart to convert ASCII characters to hex. For instance, the 2 is represented as 32 followed by a carriage return (0D). This can be entered manually or can be pasted in from a text file or spreadsheet. It is not necessary to separate each character with a space but it may make the string more readable. Always enter two digits for each character. For instance the carriage return character must be entered as 0D and not D. You can enter as many characters as needed, but you may only see a portion of the string displayed in the box. You can use your cursor keys to make other portions of the string visible Latency Limit Throughout the day many wireless devices will request packet (Internet) service on the cellular network. As more devices attach to the network latency will increase. Latency is the amount of time it takes for information to reach its destination. This can be as little as several hundred milliseconds but could increase to many seconds on a congested network. You may be able to minimize the latency using the Latency Limit feature. By default this is set to milliseconds (45 seconds). What this means is that every 45 seconds InvisiConnect and the DCM-100B will exchange information that is used to measure and adjust for latency problems. However latency may vary more often on a congested network and may require more frequent inspection. The ideal setting may require some experimentation. Later in this chapter will be a discussion about trace files. InvisiConnect can keep a record of every message sent to and received from the field device. Each message includes a time stamp. This can be used to determine the best latency limit setting. The maximum limit is milliseconds and the minimum is 500. It may seem easiest to set it to the minimum but this means that data will be exchanged more often. This may have a negative impact in two ways. First, this could increase the cost of the cellular service, which is usually based on the number of bytes exchanged in a month. It may also reach a point of diminishing returns because InvisiConnect and the DCM- 100B may be so busy exchanging latency information that the conversation between the application program and the field device may actually slow down. Therefore it is best to set the latency limit to the highest value that provides the best performance. 6-16

81 The DCM-100B itself offers an alternate method that may work as well and sometimes better than InvisiConnect s Latency Limit feature. See Section 6.8 about this Com Port Configuration Figure 6-7 Latency Limit Screen InvisiConnect is a communications port emulator. Though the application program may think it is communicating with a physical hardware port, it is actually communicating with a virtual port. You can define as many ports as you need, starting with COM5. COM1 to COM4 are reserved for actual hardware ports in the computer. If you have more than one server defined, first highlight the desired server on the main screen (Figure 6-1). For instance, if you have an AT Modem server and a Direct Serial server, and you wish to add an AT Modem com port, then highlight the AT Modem server. Now you can add new ports, edit existing ports or delete ports by selecting the appropriate button near the bottom left side of the main screen. For our example we will ADD some new com ports. The following setup screen will appear: 6-17

82 Figure 6-8 COM port Configuration Screen Adding COM Ports One or more COM ports can be activated, but there must be a license purchased for each one. To activate several COM ports at once, check the Add Range box and enter the starting and ending COM port numbers. COM ports start at COM5 because most personal computers have accommodations for four physical COM port interfaces, and those ports might still be needed for other applications. However, if additional physical COM ports are installed (such as COM5), then you must not select them for use by InvisiConnect. If only one port is needed, leave the Add Range box unchecked and select the desired COM port number Defining COM Port Settings Your application program is probably configured to communicate with the COM port or modem at a specific baud rate, parity and other settings. Set the Port Settings to match the application s settings. Be sure to set the correct flow control as discussed in Section 6.3. At the present time the Advanced setting is not used but is there to accommodate unusual flow control situations that do not follow conventional methods. Contact Metretek if this is the case. If you can change the baud rate in your application program set both for the highest setting possible. 6-18

83 MODEM Emulation Settings There are three modem emulation settings. See Section 6.4 more further details about AT modem emulation. Auto Answer: When a traditional AT modem is used and the field device calls in, the modem usually sends a RING message to the application program each time a ring signal is detected, normally every 1-2 seconds. If the modem has been configured to answer the call on its own then it will do so after a predetermined number of rings. If not, then the modem will wait for the application program to issue an ATA command, which instructs the modem to answer the call. When the DCM-100B calls in, InvisiConnect will also issue RING messages to the application program. If you would like InvisiConnect to answer the call, then check the Auto Answer box and enter the number of rings to answer the call on. This would normally be set to 1. Otherwise InvisiConnect will continue to issue RING messages to the application and wait for an ATA command from the application. The DCM-100B will eventually disconnect if the call is not answered and InvisiConnect will stop sending the RING messages. Verbose: As mentioned earlier in Section 6.4 there are two types of responses that can be returned by an AT modem, terse and verbose. If the Verbose box is checked then InvisiConnect will default to verbose responses at startup, otherwise terse. This can be changed if it receives an ATV command from the application program or restored with an ATZ command. Wait for Connection Message: After the dial command InvisiConnect will, if enabled, attempt to page the remote device and wait the specified number of seconds for a connection. After the time has expired InvisiConnect will send a NO CARRIER message to indicate that the dial out attempt has failed. This value is also represented by the S7 modem register and can be set by the application through the standard AT commands (i.e. ATS7=60). Connection Message: When a connection is made between a traditional modem and the field device they negotiate for the best baud rate depending upon the quality of the connection. After this the modem will issue a CONNECT message to the application program. Some application programs require that the final baud rate be included in the message, such as CONNECT The Connection Message field allows you to define the exact message that is required by the application. If verbose responses are used then InvisiConnect will add the carriage return and line feed characters to the front and end of your message. If terse responses are used then a carriage return will be added to the end of the message. When making an Internet connection there is no baud rate to speak of, but the application program may still expect a baud rate in the CONNECT message. Set this to the baud rate that you have defined for the COM port setting as discussed back in Section The next table contains some common connection responses. 6-19

84 Terse Response Verbose Response DESCRIPTION 1 CONNECT Connected with remote modem 5 CONNECT 1200 Connected with remote modem at 1200 baud 10 CONNECT 2400 Connected with remote modem at 2400 baud 11 CONNECT 4800 Connected with remote modem at 4800 baud 12 CONNECT 9600 Connected with remote modem at 9600 baud 16 CONNECT Connected with remote modem at baud 17 CONNECT Connected with remote modem at baud Table 6-2 Common CONNECT Responses Once all parameters have been specified select OK to return to the main screen. 6.6 InvisiConnect Trace and Alarm Files As simple as serial port and modem communications appear to be there are always problems interpreting the standards. One modem may not produce exactly the same message as another, or the method of handshaking may be implemented differently from device to device. If you have problems connecting to InvisiConnect or the remote device, there are several debugging features that may help. Trace files are readable text files that show the history of data sent and received across the COM port, and between InvisiConnect and the field devices. Trace files are stored in the same directory (folder) as the other InvisiConnect files. They can be viewed with any text editor or word processor. COM port trace files are given the filename CommPortTrace_NULL_COM?.txt where? is the actual com port number such as 5. There will be one trace file for each active COM port. Network trace files are given the filename SocketTrace_50464.txt. There is one trace file for each active server, and the filename uses the port number as an identifier, such as in this example. Alarm files are comma-delimited text files that are easily imported into spreadsheet applications. When a DCM-100B makes contact with InvisiConnect it reports its alarm status, such as low-battery conditions, tamper switch activation, and so on. These conditions are stored in the alarm trace file and they can also appear on the main screen when they are received. The alarm file is given the filename InvisiAlarms.csv. The DCM-100B s remote unit ID is also recorded in the alarm file. First, select Trace & Alarm Files from the Options pull-down menu or select the icon near the top of the screen. 6-20

85 Figure 6-9 InvisiConnect Trace Configuration Screen If you wish to enable either of the trace files, check the appropriate boxes. The size of the trace and alarm files can be limited to prevent the files from growing too large. When the limit is reached, the present trace file is renamed with an.old extension, deleting any previous.old file. If you wish to view the communications activity on the InvisiConnect main screen check the Output Data to Trace Window box. 6.7 SMS/USSD Configuration Every device connected to the Internet has an Internet protocol ( IP ) address. Devices with static IP addresses are typically servers that are always on and always ready to accept a request for communications. Their addresses are well known. Other devices, typically called clients, are assigned temporary or dynamic addresses that are only valid during the connection. At the present time a mobile device, including the DCM- 100B, is considered a client and therefore can only originate a request for an Internet connection. Therefore it cannot be contacted directly via the Internet. However the DCM-100B can be paged by sending it an SMS message. SMS (short message service) was developed to allow short text messages to be sent to cellular phones. These messages are not sent via the Internet like regular but over a radio channel designated to carry Unstructured Supplementary Services Data (USSD). When the DCM-100B receives an SMS message it will immediately call back to the primary IP address and port number that has been programmed into the unit. See Chapters-4, 5 and 8 for more information about paging and SMS. There is also a feature that allows the DCM-100B to call back to an IP address and port number that is different than the one that is programmed into the DCM-100B. This will be discussed shortly. There are three ways to send an SMS message to the DCM-100B. The first was discussed in Section 6.4. If the application program issues an ATD (dial) command to InvisiConnect then the phone number within the ATD command will be used to construct an SMS address for the DCM-100B. 6-21

86 The second method is available in the Remote Device Configuration Change screen, to be discussed in the next section. Finally, a message can be sent using the same server that you normally use to send s to friends and business associates. However some cellular service providers only allow messages to be sent from phone to phone and not from other devices such as computers or PDAs. Contact your service provider for more information. It is worth noting that SMS is a low-priority feature on some networks and they may not be delivered immediately. In many cases the SMS address of a mobile device such as a cellular phone consists partly of the phone s telephone number. For instance, if the phone number is (909) , then the address might look like @myserviceprovider.net. The SMS/USSD Configuration feature helps InvisiConnect to formulate the correct SMS address. Select SMS/USSD Configuration from the Options pull-down menu or by selecting the icon near the top of the screen. Figure 6-10 SMS/USSD Settings Screen 6-22

87 6.7.1 Enable SMS To enable SMS, check the Enable SMS/USSD box Use SMTP Mail Server A message can be sent using the same server that you normally use to send s to friends and business associates. However some cellular service providers only allow messages to be sent from phone to phone and not from other devices such as computers or PDAs. Contact your service provider for more information. If you wish to use this feature check the box and enter the following items SMTP Server Address Enter the address of your SMTP ( ) server. Your computer system s administrator will have this information From Display Name A From name is normally sent along with the message and can be any text string. Some SMTP servers may require this to be a valid name otherwise the message may not be sent. Your computer system s administrator will have more information From Address A From address is normally the address of the sender and is sent along with the message. Some SMTP servers may require this to be a valid address otherwise the message may not be sent. Your computer system s administrator will have more information Use Attached Cellular Modem In the event that you do not have an server, or if the cellular provider only allows messages to be sent from phone to phone, you can purchase a cellular modem from your service provider or from an electronics distributor. That modem will also require cellular service to be purchased. You may want to check with your provider for a list of approved modems prior to purchasing one. A cellular modem is very similar to a standard external modem except it communicates over the cellular network rather than a wired phone line. InvisiConnect uses standardized commands to make the cellular connection and to send SMS messages. If you wish to use this feature check the box and enter the following items Cellular Modem Com Port The cellular modem normally connects to your computer using a serial cable connected to one of its hardware serial ports such as COM1. Select the appropriate serial port Flow Control There may be situations in which the computer is sending data at a volume that exceeds the cellular modem s capacity to process it, or visa versa. There are several methods commonly used to control the flow of data between two serial devices, generally called handshaking or flow control. Refer to the cellular modem s documentation for the proper setting. The selections are None, Hardware or Xon/Xoff. 6-23

88 Baud Rate, Data Bits and Stop Bits Refer to the cellular modem s documentation for the proper setting Keep COM Port Open By checking this box no other programs will be able to use the cellular modem while InvisiConnect is running. For instance your browser might use the cellular modem to make Internet connections, which may interfere with InvisiConnect s ability to send SMS Modem Reset and Initialization Strings Most modems, including cellular modems, respond a set of commands called AT commands. This was originally devised by one modem manufacturer and was eventually adopted by most others. An AT-compatible modem is expected to respond in a consistent manner to these commands. Unfortunately this is not always the case and adjustments are often needed when using different types of modems. It may be necessary to issue specific instructions to your cellular modem prior to using it to send SMS messages. When InvisiConnect opens the COM port for the first time it issues the Modem Reset String first followed by the Modem Initialization String. If the Keep COM Port Open box is checked this will be the one and only time that these strings are issued. Otherwise these strings are issued each time a new SMS message is to be sent. Refer to the cellular modem s documentation to see which commands, if any, are required. For instance the Reset String might be AT&F, which restores all settings to the manufacturer s default settings, or ATZ, which restores the modem to user-defined settings that were previously saved in the modem s memory SMS / USSD Prefix and Suffix As mentioned earlier the SMS address of the DCM-100B is usually a combination of the unit s phone number preceded and/or followed by a string of characters specific to the cellular provider. A prefix is any character string that precedes the mobile device s phone number in the SMS address, and the suffix is anything that follows. For instance if the SMS address is sms@ @myserviceprovider.net then the prefix is sms@ and the suffix Your service provider will provide this information. 6-24

89 6.7.5 Override Call-Back IP Address When the DCM-100B calls InvisiConnect it normally uses the IP addresses and port numbers that have been programmed into its memory. The override feature allows the next call and the next call only to go to a different IP address and port number. This is only used when the application program issues the ATD (dial) command to InvisiConnect. InvisiConnect will then page the DCM-100B with an SMS message and the DCM-100B will call back to the alternate IP address and port number. This feature does not change the numbers that have been programmed into the DCM-100B s memory. Since every COM port is associated with a port number, it is that port number that will be used along with the override address. The port number is defined in the Server Configuration Screen. If this feature is not needed you must fill in the callback address with Here s an example of when this might be used. Suppose there are two different computer systems running InvisiConnect. The field devices normally call in to one of these systems, but there may be times when the other system wishes to communicate with the field devices. The override address will allow the devices to call the other system once, and then return to calling the original system. Either system can send the SMS message with the override address. 6-25

90 6.8 Remote Device Configuration Changes Initially the DCM-100B was configured using MP32 (see Chapter-5). There are several parameters than can be changed over the air once the unit is in service. These include the primary and secondary Internet addresses and port numbers, the access point name (APN), the call retry strategy values and the PAP user name and password. You can also control the state of several output lines on the RS-232 port and make adjustments to network latency General Information Select Change Remote Configuration from the Options pull-down menu, or select the icon near the top of the screen. The screens (shown on the next few pages) contain tabs relating to specific features. First select the remote unit I.D. of the device that you wish to change. Use the Add Remote or Delete Remote buttons as needed. If you wish to change all of the devices, check the Apply Changes to All Remote Devices box. It is important to note that only settings that are non-zero or non-blank will be sent to the DCM-100B. The Clear Settings button will return all fields to their default (zero or blank) values. Enter non-zero or non-blank values only into the items that you wish to change. Some items such as new IP addresses or APNs will be accepted but will not be used until after the current communications session has finished. Other changes go into affect immediately while the unit is still connected. If any items are modified prior to a connection, those items will be sent to the DCM-100B soon after the next connection is established. Once a connection is made you can select the Apply button at any time to make immediate changes. For instance suppose you change the PAP user name and then page the DCM-100B to call in. Shortly after connecting InvisiConnect updates the DCM-100B with the new PAP user name. While still connected you realize that you misspelled the user name. You can correct this now by retyping the user name and selecting the Apply button. The new user name will be sent to the DCM-100B while it is still connected. 6-26

91 6.8.2 Connection Information Figure 6-11 Connection Info Change Screen Last Reported Signal Strength The cellular signal strength at the field site is reported by the DCM-100B and appears on this screen as a number (1 to 5) and as a bar graph. A 5 represents the highest signal and corresponds to 5 bars on a typical cell phone display Firmware Version The DCM-100B s firmware version number is displayed here. If no number is displayed then the version number is earlier than V Change APN Address In order to connect to the Internet the cellular service provider has its own computer equipment called a gateway server. The server will usually have an APN (access point name) in the form of a domain name, such as myserviceprovider.com or a generic name such as proxy. Contact your service provider for this information. See Chapter- 5 for more information. IMPORTANT! It is extremely important that the new APN be absolutely correct. Otherwise the DCM-100B may no longer be able to contact the server and an on-site visit will be required to correct the problem! The new APN will be used after the current session has ended. 6-27

92 SMS Address In Section 6.7 we discussed SMS messages and how they can be sent to the DCM- 100B. On this screen you can enter the portion of the SMS address that lies between the prefix and suffix of the SMS address of the DCM-100B. This is usually the cellular phone number assigned to the account. The prefix and suffix must be defined using the SMS/USSD configuration screen discussed in Section 6.7. For instance suppose the entire address is The prefix is and the suffix You would enter here. Or you can enter the entire SMS address here. In this case the prefix and suffix defined here will override the ones defined on the SMS/USSD configuration screen. Check with your cellular service provider for the proper format. Some providers do not require long distance codes or country codes in the address Callback IP Address and Port When the DCM-100B calls InvisiConnect it normally uses the IP addresses and port numbers that have been programmed into its memory. This override feature allows the next call and the next call only to go to a different IP address and port number. This is only used when the SMS Now button is selected (discussed next) and does not change the numbers that have been programmed into the DCM-100B s memory. If this feature is not needed you must fill in the callback address with and the callback port number with SMS Now Selecting this button will construct and send an SMS message to the DCM-100B. When the message arrives the DCM-100B will call back to (a) one of the IP addresses and port numbers that have been programmed into its memory or (b) the callback IP address and port number if they were specified. It is worth noting that SMS is a low-priority feature on some networks and they may not be delivered immediately. 6-28

93 6.8.3 IP Address Figure 6-12 IP Address Change Screen These will be the new IP addresses and port numbers that the DCM-100B will use for future calls. See Chapter-5 for more information. Those for Alarm-3 and Alarm-4 are reserved for other applications. IMPORTANT! It is extremely important that the new Internet addresses and port numbers be absolutely correct. Otherwise the DCM-100B may no longer be able to contact the server and an on-site visit will be required to correct the problem! The new IP addresses and port numbers will be used after the current session has ended. 6-29

94 6.8.4 Call Schedule / Retry Strategy The Primary Call Retry Rate, Primary Call Retry Count and Secondary Call Retry Interval are discussed in Chapters-5 and 8. Figure 6-13 Call Schedule / Retry Strategy Change Screen There is a feature that allows the DCM-100B to call in at regular intervals regardless of all other events. This is accomplished by setting the call retry parameters to particular values. This is discussed in Chapter

95 6.8.5 PAP / Latency / Blocking Figure 6-14 PAP / Latency / Blocking Change Screen PAP User Name and Password As an added security measure some cellular service providers use Password Authentication Protocol, or PAP. In order to gain access to their Internet service you must present a user name and a password that was assigned when the cellular service was purchased. The user name or password can be any combination of printable ASCII characters, including spaces, such as Joe Smith or The total number of characters for both the user name and password cannot exceed 98 characters. The password is hidden on this screen for added security. You must enter the password twice to verify that it was entered correctly. IMPORTANT! It is extremely important that the new PAP user name and password be absolutely correct. Otherwise the DCM-100B may no longer be able to contact the server and an on-site visit will be required to correct the problem! The new PAP user name and password will be used after the current session has ended. 6-31

96 Latency Limit In Section 6.5 is a discussion about network latency and a way to reduce it on a congested network. The DCM-100B offers an alternate method that may work as well and sometimes better than InvisiConnect s Latency Limit feature. Also, the two methods can be used together. The maximum limit is 45 seconds (45000 milliseconds) and the minimum is 500 milliseconds. Any value entered between 1 and 499 is changed to 500. Setting the value to zero will disable the DCM-100B s Latency Limit feature. At each interval the DCM-100B provides information to InvisiConnect that is used to measure and adjust for latency. The ideal setting may require some experimentation. InvisiConnect can keep a record of every message sent to and received from the field device. Each message includes a time stamp. This was discussed in Section 6.6. This can be used to determine the best latency limit setting. It may seem easiest to set it to the minimum but this means that data will be exchanged more often. This could increase the cost of the cellular service, which is usually based on the number of bytes exchanged in a month. Therefore it is best to set the latency limit to the highest value that provides the best performance. Any new latency limit value goes into affect immediately Blocking Scenario: The field device sends a message to the application program and expects a response back faster than is possible on the cellular network. If a response is not received in time the device sends the same message again and perhaps several more times. In the meantime the application program is being flooded with messages and is trying its best to respond. Both sides are out of sync and the session is likely to terminate because of it. The DCM-100B offers a feature called blocking which is similar to the blocking feature offered by InvisiConnect. If a message is received from the field device it will be sent to the application program, but further messages will be discarded ( blocked ) until the application program sends a message back to the field device. Blocking can be enabled for each port if the DCM-100B has been programmed for dualport mode. Otherwise blocking only applies to Port-1. Any changes to blocking go into affect immediately. 6-32

97 6.8.6 Line Control / Port Selection There are two output lines on the DCM-100B s RS-232 port that are normally under the control of the DCM-100B. These are generally used to control the flow of data from the field device and to control an optional dual-port multiplexer board. See discussions about hardware handshaking in Chapters 5 and 8. InvisiConnect can override this and allow the lines to be controlled for other purposes. For example one of the lines could be used to activate an audio or visual alarm at the site where the DCM-100B and field device are installed. IMPORTANT! The output lines can only supply several milliamps of current. An appropriate buffer must be used if more current is required or damage will result! Figure 6-15 Line Control / Port Selection Change Screen DSR Control There is a control line on the DCM-100B s terminal block called DSR. When the DCM- 100B is configured to use hardware handshaking, DSR is used to start and stop the flow of data from the field device. For some other flow control settings this line is used to signal when a connection has been made or terminated with InvisiConnect. If the DSR line is being used in these ways then the Device Controlled button should be selected. On the DCM-100B board is a jumper (JP3) that controls the voltage level of the DSR 6-33

98 line, either ±9V or +5/0 V. See Table 2-1 for more information. A DSR On setting produces a continuous positive voltage (+9V or +5V) on the terminal block. A DSR Off setting produces a continuous negative voltage (-9V or 0V) on the terminal block. Any change made to the DSR line goes into affect immediately. Exception #1: If the DCM-100B has been configured to interface to a 6000-series corrector using the Custom #1 flow control setting, then InvisiConnect is not allowed to control the DSR line. Exception #2: If the DCM-100B has been configured to originate calls, not respond to pages and not maintain an Internet connection, then it will enter a low-power sleep mode until another call is triggered. In this case the DSR line will go to 0V. This will also happen if the DCM-100B has to enter an emergency low-power sleep mode due to a primary power failure. See Chapter-8 for information about pages, power failures and always-on Internet connections. 6-34

99 Port Select / DCD Line Control There is a control line on the DCM-100B s terminal block called DCD. When the DCM- 100B is configured for certain flow control settings, DCD is used to signal when a connection has been made or terminated with InvisiConnect. If the DCD line is being used in this way then the Device Controlled button should be selected. Metretek offers a small adapter board called the dual-port multiplexer which allows two field devices to communicate with the DCM-100B. This is discussed in Chapter-2. In this case the DCD line is used to select which of the two field devices to communicate with. Under some conditions the DCM-100B makes that decision based on several settings programmed by MP32 (see Chapter-5 & 8). If the DCD line is being used in this way then the Device Controlled button should be selected. A Select Port-1/Raise DCD setting produces a continuous positive voltage (+9V) on the terminal block or selects Port-1 on the multiplexer. A Select Port-2/Lower DCD setting produces a continuous negative voltage (-9V) on the terminal block or selects Port-2 on the multiplexer. Any change made to the DSR line goes into affect immediately. Exception #1: If the DCM-100B has been configured to interface to a 6000-series corrector using the Custom #1 flow control setting, then InvisiConnect is not allowed to control the DCD line. Exception #2: If the DCM-100B has been configured to originate calls but not to respond to pages and to maintain a permanent Internet connection, then it will enter a low-power sleep mode until another call is triggered. In this case the DCD line will go to 0V. This will also happen if the DCM-100B has to enter an emergency low-power sleep mode due to a primary power failure. See Chapter-8 for information about pages, power failures and always-on Internet connections. 6.9 Saving and Loading Configurations The first time InvisiConnect is used it creates a configuration file called Invisiconnect.cfg. All configuration parameters are automatically saved here and reloaded the next time InvisiConnect is started. There may be a need to create different configurations for different applications. In this case you can use the FILE pull down menu in the upper left-hand corner of the screen to SAVE the present configuration into another file. You can choose to OPEN a previously saved configuration at any time. Each time InvisiConnect is started it will use the file that was in use during the previous session Normal InvisiConnect Operation and Indicators When all servers are stopped the large InvisiConnect banner near the top of the screen will be red. Yellow means there are some servers running and green means all servers are running. Each server has a trace screen that can be moved and resized as you wish. 6-35

100 Each COM port status box has a red and green indicator. As data is transmitted and received these indicators provide a visual indication of port activity. These indicators can be resized and moved about the screen for better visibility. To do this point to the desired COM port and press the RIGHT button on your pointing device (ie mouse). A small selection list will appear as shown in Figure Select either Display all Ports in a Separate Window or Add Selected Ports to Separate Display Window. You can then manipulate the display as needed Terminating a Connection with a Field Device If one or more DCM-100B s are connected and the server is stopped then the connections will be terminated with all devices. There may be times when you wish to terminate a connection with only one device without stopping the server. See Figure Point to the desired COM port and press the RIGHT button on your pointing device (i.e. mouse). A small selection list will appear. Select Disconnect Session. The process of disconnecting may take a few seconds. Figure 6-16 Terminating a Connection with a Field Device 6-36

101 7.1 Introduction 7 DC-2000 DATA COLLECTION SYSTEM NOTE DC-2000 is required only if using a 6000-Series Corrector. Users of InvisiConnect can proceed to Chapter-8. When using a 6000-Series corrector, the DCM-100B acts as a transparent modem and the DC-2000 data collection system does not require any information about it. However, the 6000-Series corrector must be fully defined. This chapter deals with the basic setup parameters needed to start the communications process. It does not deal with reports or any sort of database management. Call Metretek for more information and training. 7.2 Setting up the MODBUS Server The MODBUS server acts as an Internet server on your computer and thus must be allowed access to the outside world. Most corporate computer systems use firewall technology to prevent unauthorized and potentially damaging access from outside sources. An Internet address and port number must be assigned to the MODBUS server, and these numbers must be programmed into each DCM-100B. Your computer system s administrator usually assigns this address. To minimize potential invasion, the MODBUS server and each DCM-100B exchange private information using the 64-bit data encryption standard. If this exchange fails, the MODBUS server severs the connection immediately. Start the DC-2000 Applications Launcher and select System Configuration. Figure 7-1 Starting the System Configuration 7-37

102 On the next screen select the Data Collection process. Figure 7-2 Changing the Data Collection Configuration On the next screen (Figure 7-3) select the Internet Ports tab and select the Add button near the bottom of the screen. A smaller selection window will appear. Place a checkmark in the Enabled checkbox. Select Modbus Server for the port type. The port number will be filled in automatically, and must match the port number that was programmed into the DCM-100B (see Chapter-5). If this needs to be changed hold down the CTRL key on the keyboard, point to the Port Number box and double click the pointing device (ie mouse). Then enter a new port number. Enter the Internet address that was programmed into the DCM-100B. Your computer system s administrator usually assigns this address. DC-2000 has a number of Internet servers for various Metretek products. A maximum of 255 connections are allowed at the same time for all servers. For instance if there are already 200 connections open for other products, you can only open another 55 connections for the MODBUS server. If you have 50 devices in the field and only 10 connections open, then only 10 devices will be allowed to connect at any one time. The correctors can be scheduled to call in at different times to solve for this. 7-38

103 7.3 Setting up a Call Schedule Figure 7-3 Configuring the MODBUS Server You can define a call schedule for one corrector or a group of correctors by selecting Call Configuration from the Applications Launcher. Figure 7-4 Configuring a Call Schedule 7-39

104 On the next screen select the Add button and enter in a text name for the profile. Figure 7-5 Defining a Call Profile Name On the final screen you can define specifically when the device should call in. In Figure 7-6 the corrector will call in at regular 8-hour intervals starting at 14:00:00. Select the Apply button to make the changes permanent. Figure 7-6 Defining the Call Profile Parameters 7-40

105 7.4 Defining the 6000-Series Corrector Select 5000/6000 Corrector Configuration from the Applications Launcher. Figure 7-7 Starting the Corrector Configuration Process On the next screen (Figure 7-8) select the Add button. A smaller configuration window will appear. Check the Active box and the IP Enabled box. Enter the ID number of the corrector itself, not the DCM-100B. Remember, the DCM- 100B is unknown to the system. Finish off by selecting the type of corrector being used and the call profile that was defined earlier in Section

106 Figure 7-8 Defining a New Corrector The next screen contains a large amount of setup and reporting information that is specific to the corrector. Call Metretek for more information and training. Figure 7-9 Defining the Corrector s Setup 7-42

107 Once the corrector is defined, it will appear in the list of all 6000-Series correctors. Further editing is a simple matter of selecting the unit from the list and selecting the Edit button Figure 7-10 List of all Correctors in the System Start the data collection application. A number of MODBUS connections will be opened. The system should now be ready to take calls from the corrector via the DCM-100B. 7-43

108 7-44

109 8.1 Call Retry Strategy 8 MODES OF OPERATION If the DCM-100B is configured to originate calls or Internet connections, and a call fails due to a data error or a network problem, the following retry strategy is followed: 1) The first retry will occur from 1 to 15 minutes after the original call, as defined by the Primary Call Retry Rate. 2) Subsequent calls will be made at the Primary Call Retry Rate until the Primary Call Retry Count is exhausted. 3) Once the Primary Call Retry Count is exhausted, subsequent calls will be made at the Secondary Call Retry Interval, which is defined in hours (1-15). There is no limit to the number of retries that can occur at the secondary rate. 8.2 Repetitive Call-In Schedule If the DCM-100B is configured to originate calls or Internet connections, it will do so whenever an alarm condition occurs, whenever the unit is paged or when the external field device requests a call-in. See Section 8.8 for more details. There is also a feature that allows the DCM-100B to call in at regular intervals regardless of these other events. This is accomplished by setting the call retry parameters to particular values. 1) Set the Primary Call Retry Rate and the Primary Call Retry Count to the same values, such as 5 and 5. This is how the DCM-100B knows to call in at regular intervals. 2) The last two digits of the RUID have a range of 00 to FF (hexadecimal notation), which is 0 to 255 decimal. See Chapter-11 for a decimal-to-hex conversion chart. We ll treat this as a time value in terms of seconds and call it R. 3) If the Primary Call Retry Rate and the Primary Call Retry Count are both 1, then the unit will call in every (60 + R ) seconds. The possible range is thus 60 to 315 seconds. Example: The RUID is 1234, so R is 52 seconds (34 hex = 52 decimal). The call-in rate will be = 112 seconds. 4) If the Primary Call Retry Rate and the Primary Call Retry Count are both greater than 1, then the following formula is used: (Primary Call Retry Rate x Primary Call Retry Count x Secondary Call Retry Interval x 60) + R. The possible range is thus 240 to seconds or roughly from 4 minutes to 56 hours. Example: The RUID is 1234, so R is 52 seconds (34 hex = 52 decimal). 8-1

110 The Primary Call Retry Rate and the Primary Call Retry Count are both 3. The Secondary Call Retry Interval is 1. The call-in rate will be (3 x 3 x 1 x 60) + 52 = 592 seconds, or nearly every 10 minutes. The Primary Call Retry Rate, Primary Call Retry Count and Secondary Call Retry Interval are still used normally for the call retry strategy, as described in Section 8.1. An aggressive call-in schedule may quickly drain the alkaline lantern battery. It may be necessary to use a constant dc power source in the range of Vdc. 8.3 Controlling the Flow of Data from the Field Device When the field device is a 6000-Series corrector, a special cable and handshaking scheme is used. When the DCM-100B is configured (Chapter-5), the Custom #1 setting is selected as the handshaking method. The remainder of this section deals with other field devices. There may be situations in which the field device is sending data at a volume that exceeds the DCM-100B s capacity to process it. There are several methods commonly used to control the flow of data between two serial devices, generally called handshaking Hardware Handshaking Hardware handshaking uses additional signals on the hardware interface to stop and start the flow of data from the field device. On the CNI s terminal block is an output signal called DSR. This signal would normally be connected to the CTS (clear-to-send) input line on the field device, as shown back in Figure 2-6. Initially, if InvisiConnect does not have control of the DSR line (see Section 6.8), the DSR line will be positive. A positive voltage on this line indicates that the field device may transmit data. When DSR goes negative, the field device should halt its transmission. When the connection is terminated the DSR line will go negative for a brief moment and then go positive until the next connection Software Handshaking Xon/Xoff handshaking (also called software handshaking ) uses two ASCII characters to stop and start the flow. The CNI will send an Xoff (19 decimal or 13 hex) to the field device to stop the transmission, and an Xon (17 decimal or 11 hex) to resume transmission. Once an Xoff character is sent the field device should halt its transmission. Also, if InvisiConnect does not have control of the DSR line (see Section 6.8), the DSR line will remain positive throughout the session. When the connection is terminated the DSR line will go negative for a brief moment and then go positive until the next connection None If NONE is selected and if InvisiConnect does not have control of the DSR line (see Section 6.8), the DSR line will remain positive throughout the session. When the 8-2

111 connection is terminated the DSR line will go negative for a brief moment and then go positive until the next connection. In CSD mode each byte of data from the field device is immediately passed on to the central computer, and visa versa. In this case flow control is generally not needed and NONE can be selected as the flow control method. In packet mode the data from the field device is assembled into a packet, then sent on to the central computer. A packet cannot be larger than 1400 bytes and each packet s arrival at the central computer must be verified before another can be sent. Due to latency in the cellular networks and on the Internet each exchange may take several seconds to complete. During this time it may be necessary to stop the field device from sending any more information. If the field device never sends more than 1400 bytes in one message and must receive a response before sending another message, then the flow control can be set to NONE. The actual packet size is adjustable and is discussed back in Section Some devices do not support any kind of handshaking and may have large messages to send. This is not usually a problem in CSD mode because each byte is immediately sent to the central computer. In packet mode when the user-defined packet size is reached it is sent to the server. Meanwhile the data that continues to be transmitted by the field device is stored in memory. After the previous packet has been sent another is collected, packaged and sent. The DCM-100B has the ability to store a total of about 20,000 bytes, or about 14 packets of 1400 bytes. As each packet is delivered to the server, that much space is freed up for more incoming data. However, it is possible for the field device to eventually overrun the memory if the packets are slow to be delivered to the server. This may lead to the loss of data. One possible solution is to reduce the baud rate between the field device and the DCM-100B. This may give the DCM-100B enough time to deliver packets and keep up with new data Custom #1 The Custom #1 flow control setting must be selected when interfacing to a 6000-Series corrector. InvisiConnect is not allowed to control the DSR or DCD output lines when this setting is selected. A dual-port multiplexer board cannot be used with this setting Custom #2 The Custom #2 flow control setting controls two output lines on the RS-232 port; DSR and DCD. A dual-port multiplexer board cannot be used with this setting. See Figure 8-1. When a call is being placed or answered (CSD mode) or an Internet connection is being started (packet mode), and if InvisiConnect does not have control of the DSR line (see Section 6.8), the DSR line will go positive. When a connection is made to the remote modem (CSD mode) or InvisiConnect (packet mode), and if InvisiConnect does not have control of the DCD line (see Section 6.8), the DCD line goes positive. At the end of the call if InvisiConnect does not have control of the DCD line (see Section 6.8), the DCD line goes negative. If InvisiConnect does not have control of the DSR line (see Section 6.8), the DSR line will also go negative for a moment and then return to a positive state. 8-3

112 Figure 8-1 Custom #2 Flow Control 8.4 End-of-Message Determination In CSD mode each byte of data from the field device is immediately passed on to the central computer, and visa versa. There is no need for the DCM-100B to determine when a message has ended. This is the job of the application program and the field device itself. In packet mode the DCM-100B needs to determine when a full message has been received from the field device because the entire message has to be assembled into a packet and sent to the server. If handshaking is used the DCM-100B will attempt to stop the device when the user-defined packet size has been received. A packet is built, sent to the server and the field device is then allowed to send more data. If a message is less than the user-defined packet size or not in even multiples of it then the DCM-100B must determine when the message is complete. Some field devices may end a message with a particular character like a carriage return or line feed. However for other devices these two characters may also be meaningful data. Therefore searching for a particular terminator may not work in all cases. The DCM-100B determines when a message is complete when there have been no characters received for a certain period of time. This time is programmed into the DCM-100B using MP32, discussed in Chapter-5. This value can range from 1 to milliseconds and may have to be determined experimentally milliseconds (1 second) may be a good starting point. For example, assume the entire message to be sent to the server is going to be 10,000 bytes long, and the packet size has been set to the maximum of This means there will be 7 packets sent to the server each containing 1400 bytes, and a final packet containing 200 bytes. When the field device transmits the final 200 bytes, the DCM- 100B will wait for the programmed delay time after receiving the final byte and then send the final packet to the server. 8-4

113 Choosing a value that is too low could cause a single message to be sent in several packets. A break in a message may confuse the application program and could cause it to abort the session or retry too often. Also, each packet contains the field device s message along with some overhead information used for routing and error checking. Breaking a larger message down into several packets means more overhead and could affect the cost of the cellular service. The cost of packet service is usually based on the number of bytes exchanged in a month For example suppose the delay is set to 50 milliseconds. The field device is going to send single message of ABCDEFGH. If for some reason there is a 75 ms pause between the E and F then there will be two messages sent to the application program; ABCDE and FGH. Due to latency in the cellular network, the second portion of the message may not arrive for 1-2 seconds after the first, which could cause problems for the application program. Choosing a value that is too high may cause the field device or the application to abort a session or retry too often because message were not exchanged within an acceptable period of time. 8.5 AT Modem Emulation It is likely that your field device is expecting to communicate with an AT-compatible modem attached to its serial port. AT modem commands always start with the characters AT followed by other characters that define specific operations. The final character of a command string is always a carriage return. Upon completion of a command the AT modem sends back a response in one of two formats, either terse or verbose. Terse messages are often one to two ASCII numbers followed by a carriage return character (<cr>). Verbose messages are readable ASCII messages preceded and followed by a carriage return and line feed combination (<cr><lf>). For example, when an incoming call is detected the verbose message will be <cr><lf>ring<cr><lf> whereas the terse version is simply 2<cr>. The field device may issue commands that were important to the original modem but not to the DCM-100B. In these cases the DCM-100B will return a standard response such as OK to these commands. Other commands are meaningful and the DCM-100B will act upon them. The following is a list of these commands. The DCM-100B defaults to certain settings until programmed otherwise. 8-5

114 8.5.1 ATV (response type) Command ATV, ATV0: This instructs the DCM-100B to return terse result codes starting with this command. ATV1 (default): This instructs the DCM-100B to return verbose result codes starting with this command. NOTE: An ATV command will override the Use Non-verbose Result Codes setting that was programmed by MP ATE (echo) Command An AT modem can be instructed to immediately return every character it receives. This is called echoing. The ATE command controls this function. The default is echo on. ATE, ATE0: This instructs the DCM-100B to disable echoing starting with the next command. ATE1 (default): This instructs the DCM-100B to enable echoing starting with the next command ATX (connect message type) Command After placing or answering a call the modems on each end of the line will attempt to establish a reliable connection. The modems will then produce a CONNECT message to let the field device and the central computer know that they are online with each other. Most modems can include the baud rate in the message, such as CONNECT The ATX command controls the type of CONNECT message to return. See Table 8-1 for a list of possible CONNECT responses. ATX, ATX0: This instructs the DCM-100B to return only a CONNECT message. ATX1, ATX2, ATX3, ATX4 (default): This instructs the DCM-100B to return a CONNECT xxxx message, where xxxx is the baud rate, such as CONNECT NOTE: If the Override CONNECT Message setting was programmed by MP32 then the override message will be used in place of the standard CONNECT messages ATH (hangup) Command ATH, ATH0: This instructs the DCM-100B to terminate the connection with the central computer. The normal response to this is NO CARRIER ATA (answer) Command ATA: This instructs the DCM-100B to answer an incoming call and establish a connection with the central computer. The normal response is a CONNECT message if a connection is established or NO CARRIER if one could not be established ATD (dial) Command ATDxxxx, ATDPxxxx, ATDTxxxx: This instructs the DCM-100B to establish a 8-6

115 connection to the central computer. The xxxx portion of this command is the phone number digits to dial, which would have been dialed by the original modem. The phone number is ignored because the DCM-100B has its own phone number or IP address to contact. The normal response is a CONNECT message if a connection is established or NO CARRIER if one could not be established. 8-7

116 (escape) Command +++: Once the DCM-100B has established a connection with the central computer, it can no longer respond to AT commands. However, AT modems are always looking for an escape sequence, which is +++ followed by 1 second of quiet time. This will return the DCM-100B to command mode and the unit will respond with an OK message. Following this the DCM-100B will wait 5 seconds to receive an ATH (hangup) command from the field device. If the command is received, or 5 seconds elapse, the DCM-100B will terminate the connection with the central computer and will return a NO CARRIER message to the field device AT Command Chaining AT commands can be grouped together into one string. For example, the command ATE0V1X0 commands the DCM-100B to turn off echoing, return verbose responses and send back CONNECT messages without the baud rate. However, ATA, ATH or ATD commands should be sent separately or should be the last command in a chain. These are the typical responses that the DCM-100B will return to the field device: Terse Response ( ) Verbose Response ( ) DESCRIPTION 0 OK Accepted, no error 1 CONNECT Connected with remote modem 2 RING Incoming call 3 NO CARRIER Connection with remote modem is lost 4 ERROR Command error 5 CONNECT 1200 Connected with remote modem at 1200 baud 10 CONNECT 2400 Connected with remote modem at 2400 baud 11 CONNECT 4800 Connected with remote modem at 4800 baud 12 CONNECT 9600 Connected with remote modem at 9600 baud 16 CONNECT Connected with remote modem at baud 17 CONNECT Connected with remote modem at baud Terse responses always followed by one carriage return (13 decimal, 0D hex) Verbose responses always preceded and followed by one carriage return (13 decimal, 0D hex) and one line feed (10 decimal, 0A hex) Table 8-1 DCM-100B AT Responses 8-8

117 8.6 Paging via Voice Call In CSD mode some cellular service providers allow a mobile device to originate a data call ( mobile-originate ) or to receive one ( mobile-terminate"). To receive a data call the cellular account is assigned a data phone number. However, some providers do not support mobile-terminate connections or the user may not wish to pay the additional cost of having a separate data number. Every device connected to the Internet has an Internet protocol ( IP ) address. Devices with static IP addresses are typically servers that are always on and always ready to accept a request for communications. Their addresses are well known. Other devices, typically called clients, are assigned temporary or dynamic addresses that are only valid during the connection. At the present time a mobile device, including the DCM- 100B, is considered a client and therefore can only originate a request for an Internet connection. Therefore it cannot be contacted directly via the Internet. Many cellular accounts are (or can be) assigned a voice phone number. If the DCM- 100B is configured to answer incoming phone calls it is possible to use this as a paging number which will then trigger the DCM-100B to immediately call back to the central computer. In CSD mode the unit will answer the call and will attempt to communicate with the remote modem if there is one. The call will be terminated if 30 seconds pass without a successful modem exchange or if the other end hangs up. This will trigger the unit to immediately call back to the primary phone number. In packet mode the unit will answer the call and will immediately hang up. It will then originate an Internet connection to the primary IP address and port number. Note to InvisiConnect users: InvisiConnect does not support paging using the voice or data phone number. The use of paging requires that the cellular radio be powered up at all times. If the primary power source is the alkaline lantern battery this will quickly drain the battery. It may be necessary to use a constant dc power source in the range of Vdc. 8.7 Paging via SMS Message SMS (short message service) was developed to allow short text messages to be sent to cellular phones. These messages are not sent via the Internet but over a radio channel designated to carry Unstructured Supplementary Services Data (USSD). When the DCM-100B receives an SMS message it will immediately call back to the primary IP address and port number that has been programmed into the unit. See Chapters-4, 5 and 6 for more information about paging and SMS. There is also a feature that allows the DCM-100B to call back to an IP address and port number that is different than the one that is programmed into the DCM-100B. This is discussed in Chapter

118 The cellular service provider will give you instructions on how to send text messages to the mobile device. Often the SMS address includes the account s phone number, such as @myserviceprovider.net or something similar. See Chapter-6 for more information about SMS paging using InvisiConnect. It is worth noting that SMS is a low-priority feature on some networks and they may not be delivered immediately. The use of paging requires that the cellular radio be powered up at all times. If the primary power source is the alkaline lantern battery this will quickly drain the battery. It may be necessary to use a constant dc power source in the range of Vdc. 8.8 What Causes the DCM-100B to Call In? First, the DCM-100B must be configured to originate calls. See Chapter-5 for programming instructions. Most calls are made to the primary phone number or IP address, except for Alarm Input #2, which can be assigned a different phone number or Internet address Initial Power Up or Reset Alarm Upon power-up or when the unit is reset, the DCM-100B will call in to report a unit reset alarm Tamper Alarm Section 2.12 discusses the hardware alarm inputs. One input in particular is intended to be used with a switch that is activated if the door or access panel is opened on the enclosure that houses the DCM-100B. The DCM-100B will call in to report a tamper alarm Call Retry Alarm When the next call retry time has arrived based on the call retry strategy, the DCM-100B will call in to report a call retry alarm AC-OFF Alarm This indicates that the lantern battery s voltage level was or has been below acceptable limits for more than five minutes. This may not necessarily mean that the battery needs to be replaced. Battery voltage may drop in severely cold weather, and return to normal limits as it warms up. However, repeated alarms could signal a marginal battery AC-ON Alarm This indicates that the lantern battery s voltage level has returned to an acceptable limit after being below limit for more than five minutes. This may not necessarily mean that the battery needs to be replaced. Battery voltage may drop in severely cold weather, and return to normal limits as it warms up. However, repeated alarms could signal a marginal battery. 8-10

119 8.8.6 Call Switch Alarm Section 2.8 discusses the hardware alarm inputs. On the DCM-100 board is a jumper block J2 labeled CALL. This is wired in parallel with positions 1 & 2 on the terminal block. Momentarily shorting either connection will cause the unit to place an immediate call to report a CALL switch alarm Alarm Input #1 Section 2.12 discusses the hardware alarm inputs. The DCM-100B can be configured to place an immediate call if the Alarm Input #1 positions on the terminal block are shorted. See Chapter-5 for configuration details Alarm Input #2 Section 2.12 discusses the hardware alarm inputs. The DCM-100B can be configured to place an immediate call if the Alarm Input #2 positions on the terminal block are shorted. See Chapter-5 for configuration details. Alarm #2 has the added feature of being able to call a different phone number or IP address than the ones used for all other alarms. For example, the phone number for Alarm #2 might be that of a pager or cell phone to alert someone of an immediate problem at the field site Paging The DCM-100B can be paged by calling its voice number or sending it an SMS message. See Sections 8.6 and 8.7. When the unit calls in InvisiConnect will report that the call originated due to a page. In CSD mode the unit will report a Page Received status message Activation of the DTR Line If the field device activates the DTR input line on the terminal block, the DCM-100B will call in. InvisiConnect will report that the call originated at the request of the field device. There is no status message for this condition in CSD mode Reception of an ATD Command If the DCM-100B receives an ATD (dial) command from the field device, the unit will call in. InvisiConnect will report that the call originated at the request of the field device. There is no status message for this condition in CSD mode Repetitive Call-In Time See Section 8.2 about repetitive call-in schedules. If the DCM-100B reaches the next call-in time the unit will call in but will not report an alarm condition. 8.9 Interaction with the Field Device The DCM-100B makes every attempt to behave like a traditional AT modem. Here is how it behaves under various conditions Response to an ATD (dial) Command If the field device instructs the DCM-100B to place a call with an ATD command, the DCM-100B will call the phone number or Internet address that is programmed into its memory and will attempt to make a connection with the central computer. This may take anywhere from several seconds to 30 seconds depending on network conditions. The DCM-100B will return a CONNECT message to the field device if the connection is successful and will end the session with a NO CARRIER message when the 8-11

120 connection is terminated. If the connection cannot be established a NO CARRIER message is returned. As discussed in Chapter-2 two field devices can be wired to the same DCM-100B using an optional dual-port multiplexer board. The ability to detect the ATD command from one of the field devices will depend upon which port is currently selected. For instance if Port-1 is currently selected and the device attached to Port-2 issues an ATD command, the message will be missed. It may be necessary to devise an alternate method to gain the attention of the DCM-100B, such as using the DTR input line or by allowing the field devices to trigger the alarm inputs. Later in this chapter is a discussion about dual-port mode and the ability to select one or the other port Response to the DTR Line Going Active If the DTR input line on the terminal goes positive, the DCM-100 will wait five seconds for an ATD (dial) or ATA (answer) command from the field device. If received the DCM-100 will behave as described previously for an ATD command. Otherwise a call will be placed and the DCM-100 will behave according to the Always Send Connect Message setting that was programmed by MP32. If enabled a CONNECT message will be sent to the field device once the connection with the central computer has been established. The call will end with a NO CARRIER message. As discussed in Chapter-2 two field devices can be wired to the same DCM-100B using an optional dual-port multiplexer board. Either field device can raise the DTR line but the DCM-100B will not be able to determine which device is actually asserting the line. If the wrong port is selected when this happens the DCM-100B may not see the ATD command if the field device issues one. Later in this chapter is a discussion about dualport mode and the ability to select one or the other port Calls Originated by the DCM-100B The DCM-100B may also attempt a call on its own for the reasons discussed in Section 8.8. For some of these conditions the DCM-100B can be programmed to give the field device a chance to prepare itself for communications. This is controlled by the Enable RING Result Code checkbox in MP32 (see Chapter-5). If this feature is enabled a maximum of three RING messages are transmitted to the field device, each spaced 3 seconds apart. During this time the DCM-100B is looking for an ATA (answer) command from the field device. Also during this time the red call in progress LED will blink slowly to indicate that it is waiting for a command from the field device. If an ATA command is received, the DCM-100B will call the phone number or Internet address and will attempt to make a connection with the central computer. This may take anywhere from several seconds to 30 seconds depending on network conditions. The DCM-100B will return a CONNECT message to the field device if the connection is successful and will end the session with a NO CARRIER message when the connection is terminated. If the connection cannot be established a NO CARRIER message is returned. If no ATA command is received after three ring messages, the call will be placed and there will be no further modem messages sent to the field device (such as CONNECT or NO CARRIER ). 8-12

121 The DCM-100B will not issue RING messages for the following conditions: 1) The field device requests the call, 2) The reason for the call is to report a UNIT RESET, 3) The reason for the call is to report a TAMPER alarm As discussed in Chapter-2 two field devices can be wired to the same DCM-100B using an optional dual-port multiplexer board. The ability of the field device to detect the RING message will depend upon which port is currently selected. Later in this chapter is a discussion about dual-port mode and the ability to select one or the other port Response to +++ Escape Sequence Once the DCM-100B has established a connection with the central computer it can no longer respond to AT commands. However, the DCM-100B is always looking for an escape sequence, which is +++ followed by 1 second of quiet time. This will return the DCM-100B to command mode and the unit will respond with an OK message. Following this the DCM-100B will wait 5 seconds to receive an ATH (hang up) command from the field device. If the command is received, or 5 seconds elapse, the DCM-100B will terminate the connection with the central computer and will return a NO CARRIER message to the field device Behavior when Originating a Call in CSD Mode Figure 8-2 depicts the status LEDs on the SNI-III board. Figure 8-2 DCM-100B s LED Indicators When power is first applied to the DCM-100B or when the unit is reset the green program monitor LED will light steadily for several seconds then should start flashing slowly. If the DCM-100B has been configured to originate a CSD call, it will attempt to make a call to the primary phone number that was been programmed into the DCM- 100B. The reason for the call is to report a unit reset alarm. First, the DCM-100B applies power to the cellular radio and will initialize the radio for data communications. During this time the program monitor LED will flash very slowly. When the radio is ready, the program monitor LED will flash more rapidly. 8-13

122 The cellular radio will attempt to register with the cellular network. If the radio is able to register with the network, the signal strength is checked. If the signal strength is very good the program monitor LED will flash very rapidly. If the signal strength is weak but usable the LED will flash at a somewhat slower rate. Good signal strength is equivalent to 3 or more bars on a typical cellular phone. NOTE: If the radio cannot register with the network within 60 seconds, the DCM- 100B will attempt to call again at a later time. That time is defined as either the Primary Call Retry Rate or Secondary Call Retry Rate depending upon how many attempts have been made so far. The call in progress LED will either flash or light solid red. If this LED flashes the DCM-100B is waiting for the field device to issue an AT command as described in Section When solid the DCM-100B is attempting a call. The phone number is dialed. If a connection is established with the central computer s modem the carrier detect LED will light solid red. If a link cannot be established the DCM-100B will power down the radio and try again at a later time. If a modem connection is established the transmit data and receive data lights will blink randomly, indicating that data is being exchanged with the central computer. At the end of the call the call in progress and carrier detect LEDs will turn off. If the call was not successful due to data errors or the loss of a connection the DCM-100B will attempt to call again at a later time. A CSD connection will be terminated if: The central computer terminates its connection No character has been received from either the computer or the field device for one minute The cellular connection has been lost The field device requests a hang up 4 5 minutes after the initial power-up or reset, if the DCM-100B is only allowed to originate calls and not respond to pages or incoming calls, all LEDs will turn off and the DCM-100B will go into a low-power standby mode to conserve power. Additional calls can now be made for the reasons described in Section Behavior when Answering a Call or Page in CSD Mode If the DCM-100B has been configured to answer a CSD call the cellular radio module is powered up at all times in order to detect the incoming calls. Therefore it is normally always registered with the cellular network, unless the signal strength is poor. This mode is not normally used in battery-powered applications because it would quickly discharge the battery. An external dc power source will be needed to support this mode. 8-14

123 Every 20 seconds the signal strength is checked. If the signal strength is very good the program monitor LED will flash very rapidly. If the signal strength is weak but usable the LED will flash at a somewhat slower rate. Good signal strength is equivalent to 3 or more bars on a typical cellular phone. When an incoming call is detected the DCM-100B answers the call, usually on the first ring. The call in progress LED will light solid red. The DCM-100B will attempt to establish communications with the central computer s modem. If this is successful the carrier detect LED will light solid red. If a link cannot be established within for 30 seconds the DCM-100B will terminate the call. At this point the failed call is considered to be a page and, if the DCM-100B has been configured to originate calls, will call back to the primary phone number that was programmed into the unit. If a modem connection is established the transmit data and receive data lights will blink randomly to indicate that data is being exchanged. At the end of the call the call in progress and carrier detect LEDs will turn off and the DCM-100B will go back to listening for more incoming calls. A CSD connection will be terminated if: The remote computer terminates its connection No character has been received from either the computer or the field device for one minute The cellular connection has been lost The field device requests a hang up 8.12 Behavior in Packet Mode Figure 8-2 depicts the status LEDs on the SNI-III board. When power is first applied to the DCM-100B or when the unit is reset the green program monitor LED will light steadily for several seconds then should start flashing slowly. If the DCM-100B has been configured for packet mode it will attempt to make a connection to the primary IP address that was been programmed into the DCM-100B. The reason for the call is to report a unit reset alarm. First, the DCM-100B applies power to the cellular radio and will initialize the radio for Internet communications. During this time the program monitor LED will flash very slowly. When the radio is ready the program monitor LED will flash more rapidly. The cellular radio will attempt to register with the cellular network. If the radio is able to register with the network the signal strength is checked. If the signal strength is very good the program monitor LED will flash very rapidly. If the signal strength is weak but usable the LED will flash at a somewhat slower rate. Good signal strength is equivalent to 3 or more bars on a typical cellular phone. 8-15

124 NOTE: If the radio cannot register with the network within 60 seconds the DCM- 100B will attempt to call again at a later time. That time is defined as either the Primary Call Retry Rate or Secondary Call Retry Rate depending upon how many attempts have been made so far. If the red call in progress LED flashes the DCM-100B is waiting for the field device to issue an AT command as described in Section Then the DCM- 100B will request a connection with the cellular provider. If granted the call in progress LED will light solid red. Otherwise the DCM-100B will try again at a later time. A request is made for an Internet connection to the server whose IP address was programmed into the DCM-100B. During this time the transmit data and receive data lights will blink randomly, indicating that data is being exchanged between the DCM-100B and the cellular provider. If a connection is established to the server the carrier detect LED will light solid red. If a link cannot be established, the DCM-100B will try again at a later time. The transmit data and receive data lights will blink randomly indicating that data is being exchanged between the DCM-100B and the destination server. At the end of the call the call in progress and carrier detect LEDs will turn off. If the call was not successful due to data errors or the loss of a connection the DCM-100B will attempt to call again at a later time. 4 5 minutes after the initial power-up or reset, if the DCM-100B is only allowed to originate calls and not respond to pages or maintain a permanent Internet connection, all LEDs will turn off and the DCM-100B will go into a low-power standby mode to conserve power. Additional calls can now be made for the reasons described in Section Permanent ( Always On ) Internet Connection When the DCM-100B is programmed to only originate calls it returns to a low-power standby mode after the completion of a call. This means the radio is turned off and the connection to the cellular network is terminated. When it s time to place the next call the radio must be powered up, the registration must be reestablished, a network connection requested and granted, and an Internet connection requested and granted to the data collection server. Of course all of this takes time, sometimes several minutes if the network is busy. A feature that is available from most cellular providers is an always on Internet connection. By staying connected to their system it is only necessary to request a connection to the destination server. This normally requires just a few seconds. To enable this feature program the DCM-100B for originate mode and check the 8-16

125 Maintain Internet Connection checkbox in MP32 (see Chapter-5). In this mode the DCM-100B will not be able to answer incoming calls or respond to SMS messages. In this mode the call in progress LED will remain on to indicate a permanent connection to the Internet. The remaining LED indicators will behave as they do during a normal Internet connection. The use of a permanent Internet connection requires that the cellular radio be powered up at all times. If the primary power source is the alkaline lantern battery this will quickly drain the battery. It may be necessary to use a constant dc power source in the range of Vdc Alarm Status and Maintenance in CSD Mode In CSD mode the DCM-100B replaces the field device s modem but you will still need a modem connected to your computer and your application program will still communicate with that modem. The baud rate of the computer s modem must match that of the field device. Chapter-5 has information about configuring the DCM-100B s baud rate. When using InvisiConnect the DCM-100B is able to report its remote unit I.D. and alarm status. After a successful call the alarm conditions are automatically cleared. However in CSD mode the DCM-100B acts as a transparent link between your modem and the field device and this information is not automatically sent to the computer. But there is a way to request the status, and the alarms can be inspected and cleared. In CSD mode the DCM-100B is always looking for a +-+ string from the central computer. If this string is detected then the next few characters are inspected to see if they match a particular set of commands. A single carriage return character (13 decimal or 0D hex) must terminate all strings. Upper or lower case characters are accepted. 8-17

126 COMMAND +-+CA +-+CLRALMS +-+SA +-+AA +-+AUTALMS +-+MA +-+MANALMS +-+PAxxxxxx DESCRIPTION Clear Alarms. All alarm conditions that were present at the time of the call are cleared. If the DCM-100B originated a call due to an alarm condition this command will prevent the DCM-100B from calling again. The DCM-100B will respond with an OK string after the alarms are cleared. Send Alarms. The DCM-100B will return the unit ID string followed by other strings describing any alarm or status conditions. See the next discussion about these messages. Auto Alarm Clear. When this command is received alarm conditions will be automatically cleared after each call (including this call). Therefore it is not necessary to issue the +-+CA or +-+CLRALMS command with each call. This command only needs to be issued once. The DCM-100B will respond with an OK string after this command is accepted. Manual Alarm Clear. When this command is received alarm conditions can only be cleared using the +-+CA or +-+CLRALMS command. The DCM-100B will respond with an OK string after this command is accepted. Port Address. This command is used when the optional dual-port multiplexer board is installed (see Chapter-2). Dual port mode must be enabled using the MP32 programming software (see Chapter-5). The xxxxxx portion of the command is the remote unit ID (RUID) that was assigned for Port-1 or Port-2 using MP32. After the command is issued the DCM-100B will return the following text string: CONNECTION WITH PORT xxxxxx NOW TRANSPARENT Table 8-2 CSD Mode Status Commands For the +-+SA command (send alarms), the first string sent is the unit s I.D. number, as follows: UID# xxxxxx where xxxxxx is the 6-digit remote unit ID that was programmed into the DCM-100B (see Chapter-5). If there are no alarm conditions this is the only string sent. Otherwise any of the following strings may be sent relating to status and alarm conditions: * CALL RETRY ALARM * * UNIT RESET ALARM * * TAMPER ALARM * * CALL SWITCH ALARM * * AC OFF ALARM * * AC ON ALARM * * ALARM 1 * * ALARM 2 * * PAGE RECEIVED * 8-18

127 8.15 Dual Port Operation As discussed in Chapter-2 two field devices can be wired to the same DCM-100B using an optional dual-port multiplexer board. Dual port mode must be enabled using the MP32 configuration software (Chapter-5) Port Selection Guidelines Whenever Port-1 is selected for any reason then the parameters defined for Port-1, such as baud rate, packet size, etc. are used. Likewise Port-2 parameters are used when Port-2 is selected. Dual port operation may seem a bit confusing because there are many different scenarios that can affect the selection of a port. Here are some guidelines: The Custom #1 or Custom #2 flow control setting has been chosen. Use of the dual-port multiplexer is not supported for these settings. If installed, results are unpredictable. The DCM-100B always uses Port-1 s parameters for these selections. InvisiConnect has control of the DCM-100B s port select line. Only InvisiConnect is allowed change the port selection. An incoming CSD data call is answered but no port-select command ( +-+PA ) is received. A port is selected per the route to instructions programmed by MP32. If dual-port mode has been disabled then Port-1 is selected. An incoming CSD data call is answered and a port-select command ( +-+PA ) is received. The requested port is selected. If dual-port mode has been disabled then Port-1 is selected and the command is ignored. A page is received. A port is selected per the route to instructions programmed by MP32. If dual-port mode has been disabled then Port-1 is selected. If Port-1 is selected then the return call will be placed to the primary phone number or IP address. If Port-2 is selected then the call will be placed to the secondary phone number or IP address. Any condition that causes the DCM-100B to place a call to the primary phone number or IP address. Port-1 is selected. See Section 8.8 for a list of these conditions. Any condition that causes the DCM-100B to place a call to the secondary phone number or IP address. Port-2 is selected. See Section 8.8 for a list of these conditions Using the DTR Line in Dual Port Mode As discussed earlier the DCM-100B will place a call if the DTR input line on the terminal block goes active. Once the line is asserted the DCM-100B will wait five seconds for an ATD (dial) command from the field device. Either field device can raise the DTR line but the DCM-100B will not be able to determine which device is actually asserting the line. If the wrong port is selected when this happens the DCM-100B may not see the 8-19

128 ATD command if the field device issues one. Therefore the use of the DTR line and the dual-port multiplexer may require additional thought. One important note is that the port that is active at the end of a call continues to be selected until the next call. Any activity from the other port, with the exception of the DTR line, will be missed. It may be necessary to devise an alternate method to gain the attention of the DCM- 100B. For instance the field device tied to Port-1 could use the DTR line while the other device tied to Port-2 might be wired to trigger the Alarm-2 input Low Battery Standby Mode In Section 8.8 there is a discussion about reporting low battery alarms. As mentioned battery voltage may drop in severely cold weather and return to normal limits as it warms up. However, repeated alarms could signal a marginal battery that should be replaced as soon as possible. Here is how the DCM-100B behaves before, during and after a low battery condition 1. If the voltage of the lantern battery has fallen below 3.6V for longer than 5 minutes the DCM-100B will log an AC-OFF alarm. If the unit has been configured to originate calls it will attempt to report it to the central computer. If the call fails it will try again at a later time. That time is defined as either the Primary Call Retry Rate or Secondary Call Retry Rate depending upon how many attempts have been made so far. 2. If the unit has been configured to answer phone calls, receive SMS messages or maintain a permanent IP connection, those modes are temporarily cancelled. 3. If a repetitive call-in schedule has been programmed, it is temporarily cancelled. 4. The radio will be powered down and the DCM-100B will enter a low-power sleep mode. During this time all LEDs are turned off. 5. The DCM-100B will still respond to alarm conditions and activity from the field device, and will wake up and place calls under those conditions. It will return to sleep mode after each call is placed. However, the unit will not retry calls that are unsuccessful except for the call to report the AC-OFF alarm. 6. When the lantern battery voltage has exceeded 3.6V for longer than 5 minutes the DCM-100B will log an AC-ON alarm. If the unit has been configured to originate calls it will attempt to report it to the central computer. 7. The DCM-100B will restore itself to the conditions that existed prior to the low battery condition. 8-20

129 Safety 9 SAFETY, HAZARDOUS AREAS, ESD PRECAUTIONS WARNING This product contains a radio-frequency transmitter, Motorola Model g18, FCC ID # IHDT6AC1 or Motorola Model c18, FCC ID # IHDT56CW1. This device must be installed in a manner that provides a minimum separation distance of 8 (21 cm) or more between the antenna and persons to satisfy FCC RF exposure requirements for mobile transmitting devices. Important: To comply with the FCC RF exposure limits and satisfy the categorical exclusion requirements for mobile transmitters, the transmitter effective radiated power must be less than 3.0 Watts ERP (4.9 Watts or 36.9dBm EIRP). This requires that the combination of antenna gain and feed line loss does not exceed 16 dbi. Hazardous Area Classification At the time of this publication no hazardous area safety approvals have been received for the DCM-100B product. It is therefore necessary to ensure that the product is only installed at locations that are classified as safe area sites. Safety barriers must be utilized if it becomes necessary to route any cables into a hazardous area boundary. Refer to the U.S. National Electrical Code (NEC) book, article 510, as well as any relevant local ordnance for guidance with hazardous area wiring. It is the responsibility of the user to ensure compliance with regulations regarding hazardous area locations. This may require the site to be inspected by a certified electrician to maintain full compliance. 9-1

130 ESD Handling Precautions Any electronics device contains components sensitive to ESD (electrostatic discharge). For example people experience up to 35kV ESD, typically while walking on a carpet in low humidity environments. In the same manner many electronic components can be damaged by less than 1000 volts of ESD. For this reason you must observe the following handling precautions when servicing this equipment: Always wear a conductive wrist strap. Eliminate static generators (plastics, styrofoam, and so on) in the work area. Remove nylon or polyester jackets, roll up long sleeves, and remove or tie back loose hanging neckties, jewelry, and long hair. Store and transport all static sensitive components in ESD protective containers. Disconnect all power from the unit before ESD sensitive components are removed or inserted, unless noted. Use a static safeguarded workstation, which can be set up by using an anti-static kit (Motorola part number A82). This kit includes a writes strap, two ground cords, a static control tablemat, and a static control floor mat. The Motorola part number for a replacement wrist strap that connects to the tablemat is A59. When anti-static facilities are unavailable, use the following technique to minimize the chance of damaging the equipment: o Let the static sensitive component rest on a conductive surface when you are not holding it. o When setting down or picking up the static sensitive component, make skin contact with a conductive work surface first and maintain this contact while handling the component. o If possible, maintain relative humidity of 70-75% in development labs and service shops. 9-2

131 10 TECHNICAL SPECIFICATIONS Model: Battery Types: Sleep current : Main crystal frequency: Number of inputs: Wetting current per input: Serial Port: Antenna (Internal rigid): DCM-100B, battery-powered, SNI-III based Lead acid: 6V, 3.0AHr, Yuasa brand NP3-6 or equivalent Lantern battery: 6V, Energizer brand 521 or equivalent. < 800 ua, originate mode only MHz. 4 Form-A alarm inputs 175uA nominal. Output levels on TX, DCD and DSR: ±9V max. Input levels on RX and DTR: ±15V max. Baud rate: 300 to (user-selectable) MHz, Metretek Stock # B-001 Antenna (external kit): MHz, Metretek Stock # MHz, Metretek Stock # MHz, Metretek Stock # MHz, Metretek Stock # Cellular Radio (GSM): Cellular Radio (CDMA): Antenna Connector: Motorola Model g18 Tri-Band GSM GPRS FCC ID# IHDT6AC1 Metretek Stock Number Motorola Model c18 Dual-Band CDMA 1XRTT FCC ID# IHDT56CW1 Metretek Stock Number MMCX Jack (female), 50 ohm impedance. Receive Frequencies: CDMA MHz GSM MHz GSM MHz GSM, CDMA MHz Transmit Frequencies: CDMA MHz GSM MHz GSM MHz GSM, CDMA MHz 10-1

132 Weight: Dimensions (Figure 2-4): Without lantern battery: 7.2 pounds (3.26 Kg) Lantern battery installed: 11.4 pounds (5.17 Kg) 11.5 x 9.3 x 5.35 (29.2cm x 23.6cm x 13.6cm) Operating temperature range: -22 to +140 Fahrenheit (-30 to +60 Celsius) 10-2

133 11 ASCII-HEX-DECIMAL CONVERSION CHART 11-1