Hi,

I have two different projects, with a the same problem. First off I have to read and write data, from a Siemens S71200 PLC by using TCP/IP MODBUS. The main controller type is GE Fanuc. I use the command Com_req. II need help with the action that should perform in the Siemens controller.

In the second project I have to read and write data from a boiler. The boiler data is in MODBUS 485 or 232. My PLC is again Siemens S71200.

Thanks

 

Insert an MB_SERVER FB (from one of the folders near the bottom of the Instruction task card).

Create a DB containing an array of INT's (I believe it must be non-optimized), and reference that DB symbolically as the appropriate tag on the FB. (Obviously, this is in addition to the DB required for the FB internal use) I typically call the data DB "Modbus" and the array "INT".

 

I just realized I may have misread your question about reading and writing "from" the S7-1200.

If you want the S7-1200 to be the Modbus/TCP server (waiting and responding to requests from a master or client), use MB_SERVER.

If the 1200 is going to initiate the transactions (what Modbus RTU would call the "master"), then use the MB_CLIENT FB, found in the same folder as MB_SERVER. MB_SERVER need only be inserted once, while you'll need separate MB_CLIENT boxes for each transaction (or change the parameters and call again for each transaction).