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A have a PLC Siemens S7-200 (CPU 226 COD. 6ES7 216-2BD23-OXBO) and a Simatic Panel TP177. I desire to collect data on a workstation. Is it possible to communicate directly without any additional interface? With Modbus perhaps?

Siemens does not use Modbus.
You can use
http://libnodave.sourceforge.net/index.php
if you only need a communication library
or
http://pvbrowser.org
if you also need a visualization for that.

Hi,
Sorry, but the Siemens S7-200 DOES use MODBUS, and there is a perfectly good MODBUS master available in the libraries, I have several projects running Remote IO via MODBUS from S7-200s.

The latest MODBUS Master library is v1.2 and you may use either port, MODBUS Slave is available as v1.0 only on Port 0

Marc Sinclair

http://s7-200.germainesystems.eu

pvbrowser should check the facts before he replies. Siemens has Modbus drivers for both the S7-200 and the S7-300. i think in this day and time any good PLC manufacturer that has a serial card can talk Modbus.

I know that Siemens provides Products that support Modbus also.
http://www.industry.siemens.de/IT4Industry/EN/solution_servic es/SIMATIC_Addons/proto_mod.htm

But I think that costs extra money.

The native protocol of Siemens PLC's is NOT open and has been reverse engineered by
http://libnodave.sourceforge.net/index.php
for example.
Within http://pvbrowser.org we make use of that.

The above modbus solution from Siemens is for Modbus/TCP only. If somebody knows a modbus solution from Siemens which works with an RS232/RS485 converter please let me know.

Hi,
Yes MODBUS, using the s7-200 library will work, but try Libnodave, that might
have the functionality you need.

http://libnodave.sourceforge.net/index.php

You will need the programming lead (RS485-RS232) to connect to a standard PC
serial port

Marc Sinclair
http://www.germainesystems.eu

The CPU 226 has two RS 485 ports as standard and Siemens offers a Modbus Protocol Library you can install to allow one of the ports to communicate as a Modbus Master or Slave. All you will need is a RS 485 port on your PC or an RS 485 to RS 232 converter.

Thank you,

David Adams
Application Engineer
CONTROL PRODUCTS
dadams@controlproductsinc.net
334-567-2017 office
334-567-8614 fax
334-303-9499 cell

First. Thanks to everyone.

Try to prove the libnodave.

But according to the commentary by David Adams, I feel good option, but how do I do with communication to Simatic Panel?, taking into account that I leave a free port for maintenance and scheduling.

Thank you
Juan Espejo

Jespejo,
You have a few options. Feel free to contact me at
dadams @ controlproductsinc . net and I will try to help further.

David Adams