USER MANUAL Version 1.5 Nortech Management Ltd, United Kingdom NOV 2016 www.nortechonline.co.uk Doc Ref D_000344
Publication Notice Copyright Nortech Management Limited (NML). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, including photocopying, electronic, mechanical, recording or otherwise, without the prior written permission of the copyright holder. NML provide this document as is, without warranty of any kind either expressed or implied including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. NML may make changes or improvements in the software, equipment, or specifications described in this document at any time and without notice. These changes may be incorporated in new releases of this document. This publication could contain technical inaccuracies or typographical errors. NML shall not be liable for any damages (including, but not limited to, consequential, indirect or incidental, special damages or loss of profits or data) even if NML have been informed of their potential occurrence, arising out of or in connection with this document or its use. English Edition IBM PC is a trademark of International Business Machines Inc. Windows is a trademark of Microsoft Corporation. All other trademark names used in this manual are hereby acknowledged. Nortech Management Ltd, United Kingdom Page 2 of 17
Contents 1. NX21 RTU Description 4 Operation 4 Central Host User Interface 4 Communications 4 2. Product Hardware and Lifetime support 5 3. Photograph 6 4. Wiring Connections 7 5. Commissioning / Field Support Kit 8 6. RTU Specification 9 Clock 9 Inputs / Outputs 9 RTU Events 9 Binary Inputs 9 Analogue Inputs 9 Datalogging of Analogue Inputs 10 Log Sizes 10 Input monitoring during host calls 10 Temperature 10 Signal Strength 10 Calls between RTU and Host 10 Reconfiguration of the RTU settings 10 7. Typical RTU Operation 11 Cold Start. 11 LEDs 11 Reason for the RTU to call the Host 11 Calls to the Host 11 Call Retry Algorithm 11 Incoming Calls 11 8. Communication Methods 12 Local Only 12 GSM / GPRS Modem 12 Selecting GSM or GPRS connection type 12 9. Wiring Diagram 13 10. Mounting Drawing 14 11. Specification 15 Battery Life 15 EMC Tests 15 12. Options and Accessories 16 Transducer Power Supply Daughter Board 16 NXD8 1 in, 2 out daughter board 17 Nortech Management Ltd, United Kingdom Page 3 of 17
1. NX21 RTU Description Operation The NX21 RTU (Remote Terminal Unit) is suitable for alarm and condition monitoring applications as well as datalogging applications. The NX21 monitors equipment status via digital inputs and analogue inputs. The NX21 can be supplied with a long-life lithium battery pack allowing monitoring at sites where an auxiliary supply is not available. Operational life of up to 10 years is possible between battery replacement depending on the configuration of the RTU sampling and reporting settings. Typical applications include: General plant alarm panel monitoring Tank Level Monitoring Circuit Breaker operation monitoring Telecommunication base station monitoring Central Host User Interface For UK customers the NX21 can be remotely monitored from a set of Nortech webpages called Web ihost. These are accessed via a unique username and password. Once inside the Alarm displays, events histories and NX21 configuration can be viewed and managed. For larger customers a dedicated ihost System can be installed at their own premises. The functionality of the User Interface is described in a separate document. Communications As standard the NX21 will be supplied with a quad band GSM/GPRS modem and antenna. This provides low cost wide area wireless communications between the NX21 site and the Central Host. For datalogging applications where no remote gathering of data is required then the modem can be omitted. Nortech Management Ltd, United Kingdom Page 4 of 17
2. Product Hardware and Lifetime support The NX21 product is available with either a high density set of connectors (NX61 pcb option) or a set of screw terminals (NX21 pcb option). pcb designation NX21 Photograph Comment 2 part screw terminals. Quad band modem. External SIM card holder. NX61 High density connectors. Quad band modem. External SIM card holder. Depending on the part number selected the NX21 can be supplied in a number of different packages including enclosures, batteries, brackets, cabling etc. All pcb footprints mount inside the 130x130x75 mm enclosure. Note modems vary depending on the age of the unit. Nortech Management Ltd, United Kingdom Page 5 of 17
3. Photograph NX21 pcb variant No. Description 1 Test Button and 2 LEDs for TX/RX 2 16-bit Microprocessor 3 COM1 RTU configuration port 4 Analogue Inputs 5 Digital inputs 1 8 6 Digital inputs 9 12 7 GSM/GPRS modem 8 Antenna Connection 9 SIM Card Holder 10 Battery / DC power connection 11 Temp Transducer NX61 pcb variant Nortech Management Ltd, United Kingdom Page 6 of 17
4. Wiring Connections The RTU requires a power supply from either a Long-Life lithium battery pack (in which case there is no need for any auxiliary power supply) or from a constant DC source fed via a Nortech DC Supply Board. Digital Inputs are monitored using internal pull-ups, there is no opto isolation between the RTU and the equipment being monitored. Where opto-isolation is required for a particular application plug in daughter board are available. Analogue inputs are monitored via 0-25mA inputs and are therefore suitable for use with externally powered 4-20mA sensors. There is an 18V switched DC supply available as an optional extra which can be used to supply power to external 4-20mA sensors. A wiring diagram is included in this manual. Nortech Management Ltd, United Kingdom Page 7 of 17
5. Commissioning / Field Support Kit Connect the NX21 to the PC using the NXA-0100 serial cable plugged into the RJ45 socket as shown in the earlier photograph. Run the NX-FSK Field Support Kit software on the laptop. The Field Support Kit PC software allows users to interrogate the current status and settings of the NX21 as well as look at archived logs. NXA-0100 programming lead The Field Support Kit is described in a separate document. Nortech Management Ltd, United Kingdom Page 8 of 17
6. RTU Specification Clock The RTU has an internal Real Time Clock (RTC). The clock is synchronised with the Host during every communication. Date/time stamping in Event and System logs is to 0.1 second granularity. The RTC has a drift of 1/1,000,000. Inputs / Outputs There are 12 digital inputs. These are configured to operate as Binary Inputs. There are 2 analogue inputs with 8-bit resolution each with 4 threshold settings. RTU Events Power up from cold (Cold Start) will usually be configured to initiate a call to the host. Binary Inputs The RTU reports the current status of all binary inputs to the host during every call. The RTU is able to detect binary state changes of 250ms duration or longer. Once an event has been detected then the RTU can be configured to fast scan the binary inputs for up to 4 minutes during which time inputs changes of 10ms duration will be detected. Binary inputs are configured to detect OPEN or CLOSE or BOTH changes of state. Binary inputs can be configured as latched with an associated latched timer, in this mode when a change of state occurs the RTU will ignore further changes of state on that input until the timer has expired. When a monitored change of state occurs a date/time stamped binary input change log entry is made. Binary input change of state can be configured to initiate an immediate call to the host. Analogue Inputs The RTU reports the last reading of the 8-bit analogue value of each input to the host during every call. Each analogue input has 4 threshold levels associated with it. If during a reading a threshold level has been crossed since the last reading then the RTU adds a date/time stamped entry in the analogue threshold log. The hysteresis for threshold crossings is 5. The 8-bit value of 0-255 corresponds to a 0-25mA level on the input. e.g. 200 = 19.61mA. Analogue inputs crossing threshold can be configured to be logged and initiate an immediate call to the host. It is possible to provide power to external 4-20mA type sensors via a switched output power line on the board. A Nortech DC-DC step up board is needed for this option. The powering of the external sensors can be synchronised with the reading of the analogue input levels. The 2 analogue inputs are read at configurable intervals in the range 1 to 4000 minutes. When the time for the analogue reading to occur is reached the analogues and the external switched power line are energised for a stabilise time prior to taking a readings. Nortech Management Ltd, United Kingdom Page 9 of 17
Datalogging of Analogue Inputs Analogue inputs can be configured for datalogging their value each time they are read. If enabled then the RTU stores the current level and the date/time the reading was taken. During the next contact with the Host these datalogs will be transferred. Log Sizes Logs are stored in non-volatile memory. With the standard memory the RTU can store: 100 Binary Logs 1500 Analogue threshold crossings and datalogs 100 RTU and communications events When a log fills then the 100 th (1500 th ) entry is stored as a buffer overrun and then the log loops back and overwrites the oldest data. Input monitoring during host calls Inputs continue to be monitored during calls to the Host. If a binary or analogue input event takes place during a call the Log entry is still be made. Temperature The RTU takes a temperature reading using it s on board sensor at the same time as the analogue inputs have been configured to be read. The last temperature reading taken is reported to the Host during every contact. Signal Strength The RTU monitors the GSM/GPRS signal strength during each call. The last measured signal strength is reported to the Host during every call. Calls between RTU and Host When the RTU calls the Host the Host software answers the call and initiates a transfer of data in both directions using a secure protocol. During contact with the Host the RTU acts as a slave serving information to requests by the Host acting as master. Information from the RTU is stored in the Hosts database where users may view it. Reconfiguration of the RTU settings The operational behaviour of the RTU including which inputs are enabled, how data is stored and reported to the Host and how often contact with the host is required are all configurable centrally from the Host without the need for a site visit. When a Host User makes changes to these settings at the Host the new settings will be loaded into the RTU during the next contact between the Host and the RTU. Nortech Management Ltd, United Kingdom Page 10 of 17
7. Typical RTU Operation Assumes a GSM modem is fitted. Cold Start. The RTU should be configured to monitor processor power up after periods without mains and battery back-up power, this is known as a Cold Start. The RTU will then initiate a call to the host when a Cold Start event takes place. LEDs The Processor LEDs are used to indicate current operation state of the NX21 along with communication state. Mode Green LED Red LED Normal Operation, OFF OFF Using modem, dialling, communicating etc... Follows TX End of a Successful call... 5s ON then OFF OFF Follows RX End of a failed call... OFF 5 s ON then flashing (see below) during retry algorithm. During retry algorithm... OFF Flashing 200ms ON, 2s OFF End of Retry Algorithm... same as normal operation. Flashing 200ms ON, 2s OFF OFF Reason for the RTU to call the Host When the user presses the test button the RTU initiates a call to the Host. When the Next Routine Call date/time is reached/exceeded the RTU initiates a call to the Host. When an event takes place that is configured to initiate a call to the host. Calls to the Host When the RTU initiates a call to the Host it waits the call in delay timer period before dialling. The RTU keeps track of, and reports to the Host, a set of call success statistics. Call Retry Algorithm If a call to the Host fails then the RTU retries to a total of 10 times over a period of approximately 20 minutes. The interval between retries varies between RTUs so that different RTUs don t have the same retry interval algorithm. If all 10 attempts fail then the RTU will start retrying again (another 10 attempts) 24 hours later. During this period if any other events occur requiring the RTU to call the Host it should do so in the normal manner. Incoming Calls When using the lithium battery pack the RTU switches off the modem except when required to call the Host. Therefore the Host is unable to initiate contact with the RTU. When an external DC power source is used the RTU keeps the modem powered up between calls and the Host can call ( poll ) the RTU which will answer the call. Nortech Management Ltd, United Kingdom Page 11 of 17
8. Communication Methods Local Only Plug in the Field Support Kit lead into COM1 and download onto PC the contents of the RTUs logs. GSM / GPRS Modem A GSM/GPRS modem can be directly fitted to COM 0 at Nortech. Serial communication and power is provided by this connection. The RTU communicates using the NX protocol over GSM and GPRS networks. Various settings need to be set in order for the RTU to use the GSM / GPRS modem, these will usually be configured by Nortech as part of the pre-delivery checks. A SIM card is needed to gain GSM / GPRS Network access. The SIM card needs to be CSD Data enabled and/or GPRS enabled. Selecting GSM or GPRS connection type The NX21 supports both Circuit Switched Data and GPRS connections types. The choice of which type to use is software switchable either as a factory configured option by Nortech or by the user using the Field Support Kit. Each option in turn has it s own settings which are used to connect to the Host. GPRS needs Host IP addresses setting, CSD needs Host phone numbers setting etc. The software switch is available from firmware v10 onwards. For help in deciding on which option to use please contact Nortech. Nortech Management Ltd, United Kingdom Page 12 of 17
9. Wiring Diagram Digital Inputs should be volt-free dry contacts. Analogue Inputs should be 4-20mA. Only use a lithium battery pack or DC power board supplied by Nortech. NX21 pcb variant NX61 pcb variant Nortech Management Ltd, United Kingdom Page 13 of 17
10. Mounting Drawing The NX21 can be supplied in a number of different enclosure sizes depending on the application. The standard enclosure is 130x130x75 mm and weighs approx 0.7 kg complete with the battery. Pressure equalisation vents and other features to combat condensation may be fitted on request. 130 x 130 x 75 enclosure Nortech Management Ltd, United Kingdom Page 14 of 17
11. Specification Battery Life The standard lithium battery pack is a 3.9V, 32Ah unit. The drain on the battery is affected by a number of factors including: Power supply being provided for external 4-20mA sensors. Number and length of GSM modem calls and call attempts. Configuration settings for analogue input scan interval and stabilise time. Configuration of scan duration and fast scan period of digital inputs. Input wiring impedance. Temperature. It is therefore not possible to give a firm indication of the battery expectancy without knowing details of the application and configuration settings selected. As a rough guide a battery life of between 5 and 10 years is achievable. EMC Tests Independent EMC testing has been carried out on the NX21 product and passed to the following standards. Emissions EN61326-1 EN55022 Radiated Emissions Immunity EN61326-1 EN61000-4-2 ESD EN61000-4-3 Radiated Immunity EN61000-4-8 Power Frequency Magnetic Field Environmental Enclosure Rating: Where supplied the enclosure is suitable for outdoor use. Humidity: 0-95% non condensing RTU PCB: -20 to +70 degrees C. Nortech Management Ltd, United Kingdom Page 15 of 17
12. Options and Accessories Transducer Power Supply Daughter Board The daughter board allows external 4-20mA transducers to be powered directly from the NX21. The 18V power supply output is switched by the NX21 processor and is usually synchronised with taking analogue readings. Note: The power daughter board requires a larger enclosure. The NX21 with modem and antenna, battery and daughter board can be supplied in an enclosure 180 x 182 x 90 mm. Analog Power Board Connections Nortech Management Ltd, United Kingdom Page 16 of 17
NXD8 1 in, 2 out daughter board The NXD8 requires a specific version of firmware to operate. Digital inputs 2-8 are not monitored when the NXD8 is fitted. The NX21 + NXD8 takes a single relay input, monitors it using digital input 1 and controls an output relay which can be wired to external equipment. The output relay is controlled by the NX21 to follows the status of the input relay. NXD8 Photo 1 Legend: 1: Plug into NX21 2: Output relay 3: Wiring for Input and Output relays 3 2 NXD8 Wiring connections Pin 1 Input Relay must be volt free Pin 2 Pin 3 Output Relay volt free Pin 4 NXD8 installed on NX21 3 Legend: 1: Input and Output Relay connections 2: M3 mounting screw 3: Additional mounting point if required. 4: LED and button still accessible. 2 3 4 Pin 4 Pin 3 Pin 2 Pin 1 1 Nortech Management Ltd, United Kingdom Page 17 of 17