Simens Modbus slave CP341

Siby · Dec 9, 2006

Hello
im using 3 Siemens PLC 315 2 DP these three PLCs are communicating on profibus master slave.
Now i wanted to communicate master PLC with CP341 as modbus slave but im unable to do the modbus part.
Can any body send me an example or some useful tips for communicating my 315 2 DP with CP341 .

regards

dchartier · Dec 10, 2006

Hello Siby;
Start with the following info, from Siemens' support website:

Modbus Master, Modbus Slave - New Versions and New Catalog No.'s

Concerns products with the Catalog No.'s:

6ES7 870-1AA01-0YA0 Modbus Master for CP341

6ES7 870-1AB01-0YA0 Modbus Slave for CP341

The Modbus Master and Modbus Slave loadable drivers are now available in
version 3.0 with new catalog no.'s. An upgrade is not available.

Version V3.0 permits modem operation in conjunction with a permanent
telephone line.

The new function requires version V5.0 of the configuration software,
which is included in the scope of supply of the CP341 and CP441 modules.

CP341 as Modbus Master manual:
http://support.automation.siemens.com/WW/skm/pdfviewer.asp?HitsPerSite=10&ehbid=html_76%2Fehb%2F1220184%2Ehtm&query=CP340+Loadable+drivers&lang=en&nodeid=1219437&page=1&view=new

CP341 as Modbus slave manual:
http://support.automation.siemens.com/WW/skm/pdfviewer.asp?HitsPerSite=10&ehbid=html_76%2Fehb%2F1218007%2Ehtm&query=CP341+Modbus+slave&lang=en&nodeid=1219196&page=1&view=new

You will need 3 CP341 (one in each PLC rack), one Modbus Master and 2 Modbus slave licences (they are not cheap), and use the parametrization software and communication FBs included in the CP341 Modbus packages.

In the manuals you will find example applicatios for your Modbus comms.

By the way, if you have already setup communications between the CPUs through Profibus-DP, you will find it much more expensive and program intensive to do the same through Modbus. Is there any reason you would want to?

Hope this helps,
Daniel Chartier

BobB · Dec 10, 2006

There is a much cheaper way - someone here recommended it to me. A Profibus slave with Modbus master and slave built in and USS as well. I will see if I can find what I bought - it works well. Less than half the price.

Simens Modbus slave CP341

Siby

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dchartier

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BobB

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