Sahebanna

How to read the data using CP1W-CIF11 add-on card in CJ2M-CPU33

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Hi, I am using CJ2M-CPU33 PLC with CP1W-CIF11 card. I want to read the Energy meter data (Energy meter part number - Conzerv-EM6400) through CIF11 card. energy meter will have RS485 communication facility (Modbus-RTU protocol). What are the settings to be done in CPU settings and what is the procedure to read the data.

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There is information on Modbus in the Omron part of the download section on this site. I use an SCB for Modbus myself so have not explored the possibilities of this device. Edited by BobB

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The built in slot on a CJ2M does not support Modbus/RTU.To support Modbus as a Master or Slave requires an SCU module attached to the PLC.The Modbus Slave function is built in. There is code for Modbus Master here... http://forums.mrplc.com/index.php?app=downloads&showfile=867

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Obviously the SCU is the best way but... I haven't done this with a CJ2M, but I do it often on a CP1H and I see no difference. You can set the serial port for the CIF11 as Serial Gateway, create Modbus message and send it using the TXD and RXD instructions. Obviously this is more work, but it can be done. Edited by sbaum

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I believe that PMCR meant that the Easy Modbus function does not work with the CJ2M. That is the difference between using the CP1 family in this fashion and the CJ2M. It is indeed a whole lot more work without Easy Modbus (or protocol macro).

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The CJ1, CJ2, and CS1 support only 1 of the 4 protocols defined by Serial Gateway, specifically Compoway/F. The CP1L, CP1H, and CS or CJ SCU modules support all 4: Modbus/RTU, Modbus ASCII, Compoway/F, and Hostlink. In the CJ2, you could use RS232 mode to send Modbus commands, but you need to calculate the CRC16 checksum on your own, as well as handle the timeout. There are no instructions in the CJ PLCs that will calculate the CRC16 for you. The much simpler approach is the use of an SCU module, and the code provided in this forum.

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No, this cannot be done. CJ2M only support FINS 2803 for Serial Gateway, which is CompoWay/F. 2804 is not supported by the CJ, other than on a CJ1W-SCUxx module.

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Oops, unfortunately I've deleted my previous post so it looks as if PMCR responded to his own post. To clarify, I pointed out that maybe PMCR function with ModbusRTU conversion mode (2804 command) could be used with CIF board, as it would be cheaper than buying SCU module. However it seems that ModbusRTU conversion does not work with CJ-series PLC. Still it is strange that cheaper CP-series support it and CJ does not.

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