S7-200 RS-485 Capabilities.

I have a customer asking for a quote on equipment that includes an interface to their Johnson Controls equipment using RS-485 or Modbus. So far the information is very vague and I'm hoping someone with experience in this area can let me know some options while I try to drag more details from them.

Hello DesertDog;The following link will take you to Siemens' S7-200 Tips and Tricks page, Communication section:

http://www2.automation.siemens.com/microset/html_76/support/tipps/tt-kommunizieren.htm

You will find a demo for setting up the S7-200 as a Modbus slave. Code is also available.

There is also a Modbus Toolkit you can buy for the S7-200, if you don't feel at ease with the first solution.

Hope this helps,
Daniel Chartier

Thank you very much. It looks like what I need. If I'm correct this would require their system to be the Master and I would make the desired data available for them to poll.

Will I need a PPI Cable for this?

S7 200 plcs communicates over rs 485..if the customer's equipments has rs 485 ports..then all you need is a straight D9 male connector and a cable..
however, to program the S7 200 plc you need pc/ppi cable!


hope this help.k