CI853 Modbus Communication with Slave

Hello all. I am trying to communicate AC800M CI853 with a slave device (GE Fanuc PLC).

GE fanuc has RS-485 communciation module. I have downloaded the already built projects and setup the wiring correctly. But i am still unable to communcate with AC800M. All the communication parameters (baud/parity etc) are same for AC800M & GE Fanuc PLC. The projects area already ruunig in the plant. I am setting up this for a simulation purpose inhouse. Kindly suggest solutions

Thanks

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MichaelStarc Rank: 284

Asked 4 years ago

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Hi,

First of all CI853 supports RS232C Modbus, so if you want to use with a RS485 slave device. You have to use RS232/RS485 convertor.

Also there is an application called Modbus Configuration CI853, please use that manaul.

http://www402.abbext.com/MODBUS-Confi...

I hope it helps you.

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Titus

Rank: 7

Answered 4 years ago

Hello Titus thanks for your reply. I m already using the converter for comm. One more thing is i want to communicate with my serial link program (that works perfectly in the running plant) which uses one CI853 card. I just want to using a Modbus simulator to see if the values are updating in the modbus map. But it connects with the AC800M but gives the following codes in the MB Connect block (4901) & (4929). My target is just to communicate directly with the CI853 using Serial comm cable and see the values updating in the control builder program using a Modbus Simulator like Modpoll or any other which is connected directly with the CI853.

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MichaelStarc Rank: 284

Answered 4 years ago

Modbus Poll is a modbus Master Simulator - which wont work. You need to use Modbus Slave ...

http://www.modbustools.com/modbus_slave.asp

If it works in the plant then it should work on your simulator with no changes in the PLC code. So the problem must be in your simulator or cable connection. Modbus serial links do not use special controls on the serial link so pretty much any serial to USB converter should work properly. ( if you need to use one )

You may find that you need to move the modbus address registers up or down by 1 ( some modbus implementations use a zero based register instead of a 1 based register) but otherwise everything should be OK.

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Rob Lyon

Rank: 2

Answered 4 years ago

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CI853 Modbus Communication with Slave

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