3710 ACM 3750 PDC 3800 RTU. ISOCOM Communications Card Retrofit Instructions

Transcription

1 3710 ACM 3750 PDC 3800 RTU ISOCOM Communications Card Retrofit Instructions

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3 Danger During normal operation of this device, hazardous voltages are present which can cause severe injury or death. These voltages are present on the terminal strips of the device and throughout the connected potential transformer (PT), current transformer (CT), status input, relay, and control power circuits. Installation and servicing should be performed only by qualified, properly trained personnel. See the Installation and Operation Manual for the specific device for additional warnings. Warning This equipment generates, uses, and can radiate radio frequency energy and if not installed and used in accordance with the instructions manual, may cause interference to radio communications. It has been tested and found to comply with the limits for a Class A computing device pursuant to Part 15 of FCC Rules, which are designed to provide reasonable protection against such interference when operated in a commercial environment. Operation of this equipment in a residential area may cause interference in which case the operator will be required to take whatever measures may be required to correct the interference. Limitation of Liability Power Measurement Limited reserves the right to make changes in the devices or the device specifications identified in this Retrofit Installation Instructions without notice. Power Measurement Limited advises customers to obtain the latest version of device specifications before placing orders to verify that the information being relied upon by the customer is current. In the absence of written agreement to the contrarypower Measurement Limited assumes no liability for Power Measurement Limited applications assistance, customer's system design, or infringement of patents or copyrights of third parties by or arising from the use of devices described herein. Nor does Power Measurement Limited warrant or represent that any license, either expressed or implied, is granted under any patent right, copyright, or other intellectual property right of Power Measurement Limited covering or relating to any combination, machine, or process in which such device might be used. For further information or technical assistance, please contact your local Power Measurement representative, or Customer Service at one of the following locations: World Wide Web support@pml.com Worldwide Headquarters POWER MEASUREMENT LTD Keating Cross Rd., Saanichton, B.C., Canada V8M 2A5 Tel: Fax: Europe & Middle East POWER MEASUREMENT EUROPE Bayreuther Str. 6 D Forchheim Germany Tel: Fax: Asia & Pacific POWER MEASUREMENT AUSTRALIA Unit 7/16 Ledgar Road, Balcatta, Perth, Western Australia 6021 Tel: Fax: EXCEPT TO THE EXTENT PROHIBITED BY APPLICABLE LAW, UNDER NO CIRCUMSTANCES SHALL POWER MEASUREMENT LIMITED BE LIABLE FOR CONSEQUENTIAL DAMAGES SUSTAINED IN CONNECTION WITH SAID PRODUCT AND POWER MEASUREMENT LIMITED NEITHER ASSUMES NOR AUTHORIZES ANY REPRESENTATIVE OR OTHER PERSON TO ASSUME FOR IT ANY OBLIGATION OR LIABILITY OTHER THAN SUCH AS IS EXPRESSLY SET FORTH HEREIN. ISO Registration Cert # Revision Date: June 8, Power Measurement Ltd. All rights reserved Printed in Canada

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5 Introduction NOTE For complete communication port details, refer to the Installation & Operation Manual for the specific device. The ISOCOM communications card provides a remote communications port for the following compatible instrumentation packages: 3710 ACM (Rev A & Rev B) power meters 3750 PDC power demand controller 3800 Mini RTU NOTE Two models of the ISOCOM are manufactured by PML, the ISOCOM and ISOCOM2. The ISOCOM2 card is not compatible with the devices listed above. The ISOCOM is a direct replacement for the previously used C01 card. Communications using either the RS-232C or RS-485 standards is possible. Improvements include full isolation for both RS-232C and RS-485. Optical coupling provides isolation between the communications lines and the metering equipment. Protection circuitry provides protection from common mode voltages and incorrect connection of the ISOCOM. All inputs pass the ANSI/IEEE C37-90A-1989 surge withstand and fast transient tests. This document describes the steps necessary to retrofit any device listed above with an ISOCOM card. Configuration instructions and wiring requirements for direct connection with a master computer station are provided. Refer to the Installation and Operation Manual for the device for additional information regarding remote connections made via modem. ;%62-2 It is important that all instructions provided in this document are performed exactly as described to avoid injury and to ensure the device is protected from any damage. Installation Procedure You will require the following tools to install the ISOCOM: 1. One Philips screwdriver. 2. An anti-static wrist strap or equivalent protection.

6 Preparing the 3710 ACM, 3750 PDC or 3800 RTU for Installation (%2)6 During normal operation of the 3710 ACM, 3750 PDC, or 3800 RTU, hazardous voltages are present which can cause severe injury or death. These voltages are present on the terminal strips of the device and throughout the connected potential transformer (PT), current transformer (CT), status input, relay, and control power circuits. Installation and servicing should be performed only by qualified, properly trained personnel. To prepare the 3710 ACM, 3750 PDC, or 3800 RTU for installation: 1. Open all PT fuses (or direct voltage input fuses) and close all CT shorting blocks. 2. Turn off all power to the 3710 ACM, 3750 PDC, or 3800 RTU and disconnect the Line and Neutral (or DC power) wires from the Power inputs to the unit. 3. Disconnect all other wiring (or power off all other circuits) which may present potentially hazardous voltage levels to the unit, such as connections to the relay outputs, status inputs, etc. 4. Ensure that all cables still connected to the device are NOT live. Removing the Existing CO1 Communications Card CAUTION The components inside the device are extremely sensitive to staticelectric discharge. To prevent damage to the unit, wear an antistatic wrist strap at all times when working inside the unit. Failure to use proper equipment during servicing will void the warranty. The existing CO1 Communications Card must be removed before you can install the new ISOCOM. You can remove the CO1 while the unit is still mounted in its switchgear panel (or other mounting location). The CO1 is on the right of the 3710 ACM, 3750 PDC, or 3800 RTU rear panel as depicted below:

7 ISOCOM Card Installation 1. Carefully disconnect all communication wiring from the existing card. 2. Remove the four machine screws from the rectangular communications card mounting plate with the screwdriver. 3. Pulling the plate away from the rear panel will remove the CO1 from the device. CAUTION Touch the ISOCOM only by the sides of the card or by the metal mounting plate to prevent damage to its components. The ISOCOM consists of a metal mounting plate and a barrier terminal strip connector. The mounting plate is attached to a circuit board which has a row of contacts that plug into a matching edge connector socket inside the base unit.

8 To install the ISOCOM Card: 1. Touch the side of the 3710 ACM, 3750 PDC, or 3800 RTU chassis to ground any static charge that could damage electronic components when installing the ISOCOM. 2. Locate the socket where the CO1 was previously inserted. 3. Hold the ISOCOM by the metal mounting plate and lower it into the base unit so that the two LED s face the outside edge of the case. 4. Line up the edge of the circuit board with the edge connector socket and press the ISOCOM firmly into place. The ISOCOM will be securely inserted into the socket when the mounting plate meets the chassis. The ISOCOM mounting plate is shown below: Final Steps 1. Align the holes in the metal mounting plate of the ISOCOM with the mounting holes on the base unit. Use the Philips screwdriver to replace the four machine screws. 2. Reinstall the Line and Neutral (or DC power) wiring to the Power inputs of the unit. 3. Reconnect all other wiring (or re-enable all other circuits). Close the PT fuses (or direct voltage input fuses) and open the CT shorting blocks. Turn on power to the device and verify the correct operation.

9 Terminal and LED Functions 7KH,62&20FRPPXQLFDWLRQVFDUGSURYLGHVDEDUULHUVW\OHWHUPLQDOVWULS7HUPLQDO IXQFWLRQVLQFOXGH Ground GND Chassis Ground RS-485 RS-485 Shield (electrically connected to chassis ground) - RS-485 Data Minus RS-485 Data Plus RS-232C RXD RS-232C Receive Data (i.e. data into device) TXD RS-232C Transmit Data (i.e. data out of device) SG RS-232C Signal Ground RTS RS-232C Request To Send (optional, see Chapter 6 ) Two LED indicators, TXD and RXD, show activity on the RS-485 or RS-232C communications lines and can be used to verify correct communications operation. The TXD indicator flashes when data is sent out by the device. The RXD indicator flashes when data is received by the device. RS-232C Connections NOTE Use of the RTS and CTS lines is optional. Some types of modems (e.g. radio modems) may require the use of these lines. The figure on the following page illustrates all RS-232C cable configurations and wiring connections. The cable used between a computer and modem (if used) is a standard straighthrough RS-232C communications cable with a maximum length of 50 feet (15.2 m). Refer to the installation manuals for both the computer and modem for cable requirements. Typically, a computer is configured as a DTE device, whereas a modem is configured as a DCE device. Note that this is not always the case; refer to the manual for the computer or modem for correct configuration. The cables used between a DTE or DCE device and an ISOCOM equipped device are each custom RS-232C cables. In each case, one end is equipped with a DB25 or DB9, male or female connector. The connector required depends on the mating connector of the DTE or DCE device serial port. The other end of the cable consists of discrete wires which connect to the RS-232C terminals of the ISOCOM. Cable length is 50 feet (15.2 m) maximum.

10 RS-232C Serial Cable Wiring Connections DB9 Pins (Male) DB25 Pins (Male) DB9 Pins (Female) DB25 Pins (Female) Always jumper RTS to CTS at computer end. Always jumper DSR to DTR at modem end. Jumper RTS to CTS at modem end if not Always jumper DSR to DTR at modem end. DTE ISOCOM RS-232C Port DB9 DB25 Function Function 3 2 TX RXD 2 3 RX TXD 5 7 Signal Ground SG 7 4 RTS RTS 8 5 CTS CTS 6 6 DSR 4 20 DTR DCE ISOCOM RS-232C Port DB9 DB25 Function Function 2 3 TX RXD 3 2 RX TXD 5 7 Signal Ground SG 7 4 RTS RTS 8 5 CTS CTS 6 6 DSR 4 20 DTR

11 RS-485 Connections RS-485 communications allows multiple devices to be connected on the same bus. Up to 32 devices can be connected on a single RS-485 bus, which consists of a shielded twisted pair cable. The overall length of the RS-485 cable connecting all devices cannot exceed 4000 ft. (1219 m). To connect an RS-485 communications bus to a computer or other RS-232C equipped device, an RS-232C to RS-485 converter is required, such as Power Measurement s COM32 TM or COM128 TM. The COM32 offers a single RS-485 port, while the COM128 offers a total of four RS-485 ports that can each support up to 32 devices. CAUTION Do not connect ground to the shield at both ends of a segment. Doing so allows ground loop currents to flow in the shield, inducing noise into the communications cable. General Bus Wiring Considerations s connected on the bus, including ISOCOM equipped devices, converter(s) and other instrumentation, must be wired as follows: Use a good quality shielded twisted pair cable for each RS-485 bus. It is recommended that AWG 22 (0.33 square mm) or larger conductor size be used. Ensure that the polarity is correct when connecting to the RS-485 port () and (-) terminals of each device. The shield of each segment of the RS-485 cable must be connected to ground at one end only. Isolate cables as much as possible from sources of electrical noise. Use an intermediate terminal strip to connect each device to the bus. This allows for easy removal of a device for servicing if necessary. CORRECT METHOD RS-485 Cable Terminal Strip To next device To next device Distance X Terminal Strip DO NOT CONNECT! 3-way T connection point NOT ALLOWED To next device To next device

12 Recommended Topologies s on an RS-485 bus are connected in a point-to-point configuration, with the () and (-) terminals of each device connected to the associated terminals on the next device. While there are many topologies that can be used to connect devices on an RS-485 communication bus, the two recommended methods are the straight-line and loop topologies. NOTE The COM128 can support up to four RS-485 buses simultaneously. The converter can exist at any position on the RS-485 bus, including an end point. Straight-Line Topology Terminate each device at the end point of a straight-line bus with a 1/4 watt resistor connected between the () and (-) terminals. These termination resistors reduce signal reflections that may corrupt data on the bus. The resistor should match the line impedance of the cable being used. For AWG 22 (0.33 square mm) shielded twisted pair cable, values between 150 and 300 ohms are typical. Consult the cable manufacturer s documentation for the exact impedance of your cable. RS-232 to RS-485 Converter RS485 Cable Last R T Last R T Loop Topology One advantage of the loop topology is that a single open circuit fault condition anywhere on the loop will not result in the loss of communication between the computer station and any of the remote devices. The loop topology does not require termination resistors at any point on the bus. RS-232 to RS-485 Converter RS485 Cable

13 Calculating Overall Cable Length When determining the overall length of an RS-485 communication straight-line or loop connection, it is important to account for all cable segments. For example, when RS-485 connections to the device are made via an intermediate terminal block, the lengths of cable between the device and the terminal block must be added to the total cable distance. This length is equal to 2 times distance X in the diagram on page 8. Connection Methods to Avoid Any device connection that causes a branch in the main RS-485 bus should be avoided. This includes star and tee (T) methods. These wiring methods cause signal reflections that may cause interference. RULE OF THUMB At any connection point on the RS- 485 bus, no more than two cables should be connected. This includes connection points on instruments, converters, and terminal strips. Following this guideline ensures that both star and tee connections are avoided. DO NOT CONNECT! 3-way Star connection point NOT ALLOWED RS-232 to RS-485 Converter RS485 Cable DO NOT CONNECT! RS-232 to RS-485 Converter 3-way T connection point NOT ALLOWED

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16 U~ Revision date: June 8, 2000