communication between PLC-PC-micromaster

I was wondering if anyone could explain me a little bit about the connection over the RS485port from our PLC (S7-200 siemens) to our micromaster frequency variator.

In the following attachment you see that we send caracters over our RS485 port to another device (mcromaster or PC) The PC is not programmed to understand these caracters I think. Is this a special code so we can drive our motors through our micromaster frequency variator?

Which protocol is used to drive the micromaster over this port?

Where can I find the technical information abot this particular protocol?

Thanks...

Juan

Micromaster speaks the USS protocol.It's a Siemens proprietary protocol, so it is not pubblic.

Look at this

http://www.sea.siemens.com/drivesbu/support/vc_compend/Compend_AD Chapter 8_part1.pdf

but ...

Thanks,

But the schematic shown above, is this a typical communication between a PLC and a micromaster?

Download these "tips & tricks" for Simatic S7 200 (Select the language before)

http://www4.ad.siemens.de/csinfo/li...sinfo&wttree=shopnodes&lang=it&objID=11771729

ID: 1232912

Then look at Tips # 28, it explains S7200 and Micromaster connection and control

Hi
Normaly is using Profibus communication betwine Plc and F-converter. But in PLC S7-200 can not run like a master. You need S7-300. It is posible by USS protocol but is not friendly, and also you cant run USS and PPI protocol in the same time. When PLC is in stop mode the port is automatic configured for PPI communication, and if you use USS protocol when plc is in run mode is not posible tu see status by this port. You need Profibus card EM277 to see status or PLC with too ports.



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