Hello; Siemens has an add-on product to MicroWin that they call Instruction Library Toolbox (order no. 6ES7830-2BC00-0YX0) Here is a quote from their website: STEP 7-Micro/WIN32 Add-On: Instruction Library This CD adds instruction libraries to the standard STEP-7 Micro/WIN Version 3.2 programming software. This new Micro/WIN Add-On Instruction Library adds two library folders to the STEP 7-Micro/WIN for the following communication protocols: USS Protocol: The newly improved USS protocol library supports both the Micro-Master 3 (MM3) and Micro-Master 4 (MM4) drives.

The USS protocol library makes controlling Micro-Master drives easier by including pre-configured subroutines and interrupt routines that are specifically designed for using the USS protocol to communicate with the drive. With the USS instructions, you can control the physical drive and the read/write drive parameters. MODBUS® Protocol: The additional MODBUS® protocol library makes communicating to MODBUS® master devices easier by including pre-configured subroutines and interrupt routines that are specifically designed for MODBUS® communication. With the MODBUS® slave protocol Instructions, you can configure the S7-200 to act as a MODBUS® RTU slave device and communicate to MODBUS® master devices. Hope this helps, Daniel Chartier.

I have tried the Modbus master program but it's not working. You see, i'm new with modbus, it just so happened that the device that I am going to read from (the modbus slave) is an Intellisys controller by Ingersoll-Rand; it has a 2-stop bit property (can not be changed!) and the S7-200 is by default a 1 stop bit device which can not also be changed. Is this the main reason why the modbus master program is not working?

Is there anybody who has already communicated with Intellisys SG controller or IRI with S7-200 via Modbus, I am very much willing to give a software authorization in return, (Step 7 V5.3 authorization!). How about that? Thanks a lot.

SIMATIC S7-200 Controller pdf manual download. S7 open modbus / tcp communication via the integrated pn interface of the plc (62 pages). S7-200 network master. In both sample networks, the S7-200 CPU is a slave Figure 7-10 Single-Master PPI Network that responds to requests from the master. Soal gerbang logika. For a single-master PPI network, configure STEP.