SATEC POWERMETERS SATEC COMMUNICATION DRIVER FOR ALLEN-BRADLEY 1771-DB BASIC MODULE Installation and Operation Manual SATEC Ltd.
The driver is provided "as is" without any warranty of any kind. The entire risk to the results is assumed by the user. Those responsible for applying and using this product must satisfy themselves as to the acceptability of each application and the use of the product. No patent liability is assumed by the manufacturer with respect to the use of information, circuits, equipment or software described in this text.
Table of Contents 1 ABOUT THE COMMUNICATION DRIVER...................................................4 2 INSTALLATION...............................................................................................5 2.1 2.2 2.3 2.4 EPROM Installation ..................................................................................5 BASIC Module Peripheral Port Configuration...........................................5 Powermeters Communications Settings .................................................
1 ABOUT THE COMMUNICATION DRIVER • The driver provides data exchange between the PLC-2, PLC-3 and PLC-5 programmable controllers, and SATEC Powermeters via the 1771-DB BASIC module. • The EPROM firmware versions can be supplied for 1 to 31 instruments. • Two data sets are available upon order. For available data sets, refer to Appendix A. • Two additional options are available upon order. The first is communication error reporting to the PLC processor (the option is refered to as the E option).
2 INSTALLATION 2.1 EPROM Installation The SATEC communication driver is supplied in 32 Kbyte EPROM memory modules. The version of the driver is marked on the EPROM label by a combination of: X - XX - R E Data set (1, 2) The number of instruments (1-31) Reset option Error reporting option Before installing the EPROM in the memory module socket, configure the socket for a 32 Kbyte PROM size by setting a configuration jumper in the BASIC module.
For RS-422 balanced data transmission, a twisted pair cable should be used for each communication link. To minimize reflections and reduce cross talk, it is recommended to terminate the ends of lines with the termination resistor of 120 Ω, as shown in Appendix B.2.1. When lines are routed through electrically noisy environment, input protection against switching or lightning induced surge voltages is required in addition to line termination.
3 GENERAL OPERATION 3.1 Interfacing to the BASIC Module The BASIC module interfaces with the PLC processor via the PLC backplane interface. Data is transferred through the block-transfer-read (BTR) and block-transfer-write (BTW) buffers as 16-bit unsigned integers up to 65535. The data to be sent to the BASIC module must be placed in the BTW buffer. The size, configuration, and contents of the BTW buffer are discussed in Section 4.2. The data to be sent to the processor is placed into the BTR buffer.
4 APPLICATION INFORMATION 4.1 Acquiring Data From the BASIC Module 4.1.1 Data Sets #1 and #2 The driver reads measured values from the Powermeters and transfers them to the PLC processor via the BTR buffer in suitable format. There are two versions of the driver available that have different data sets being transmitted to the processor. The BTR buffer structures are shown in Appendix A. To transfer numbers greater than 65535 or between 0 and 1, a special technique is used.
2. The phase A reactive power of value -130,750 kvar is transferred as: word 34 = 750 word 35 = 13 word 36 = 1 The actual value is - (13*10000 + 750) = -130,750 Total active power is transferred only for positive values. In the case of the negative total power, the value will be zeroed. 4.1.2 Error Reporting When the E option is used, the status of the instrument being polled is always reported in word 64 of the BTR buffer.
5 TROUBLESHOOTING This chapter describes common problems you might encounter during installation of the communication driver and offers suggestions for corrective action. The processor doesn't interface to the BASIC module The symptom indicating the problem is that the address of the instrument being polled that is located in word 1 in the processor input data file is still unchanged while you are monitoring the file.
1. Check whether the processor is in RUN mode. 2. Make sure the I/O configuration settings for the BASIC module slot are correct. 3. Check whether your ladder program is correct. The BASIC module doesn't interface to the instruments The following symptoms indicate that the communications do not operate properly: 1. A non-zero error code is received by the processor in word 64 in the BTR buffer when you are using the driver with E option. 2. No data transfer occurs when you have the driver without E option.
6 ORDERING INFORMATION The ordering number is formed by a combination of: AB 1771-DB DRIVER VERSION X - XX - R Data set (1, 2) The number of instruments (1-31) Reset option Error reporting option Example: order for 16 instruments, data set #2, plus reset option: AB 1771-DB DRIVER VERSION 2-16-R 12 E
APPENDIX A DATA SETS Table A-1 Data set #1 Field No.
Table A-2 Data set #2 Field No.
APPENDIX B CABLE DRAWINGS B.
B.2 RS-422 Cable Configuration B.2.1 RS-422 Connection Series PM-280/288/270/290 1771-DB BASIC module Powermeters 2 TxD DB9 male connector 3 6 7 1 RxD 16 R1 RxD TxD 14 TxD**R3 RxD- **R4 GND RxD' 18 TxD' 25 COM 7 4 Series PM-290H Powermeters 6 DB9 male connector 7 8 9 1 5 TxD DB25 male connector RxD TxDRxDGND Series PM-170 Powermeters 14 DB25 male connector 15 16 17 1 TxD RxD TxDRxDGND *R2 R1,R2 - 120 Ω R3,R4 - 1.
B.2.