s7 1200 multiple mb client blocks

pauly

Member
Join Date
May 2002
Location
South Wales,U.k
Posts
244
I am looking for some assistance with Modbus tcp/ip to read and write data to a third party plc. I can read data with one mb client instruction but when I add a second mb client instruction to write data, comms stops with the read instruction staying at busy and no data can be read. Every example I see describes modbus tcp/ip connections between 2 s7 1200 controllers. This makes sense because the two client instructions for read and write have equivalent server instructions with different ip port numbers. If I have 2 client blocks which I want to use 1 to read and 1 to write data to the same I.p address, how can I assign different ip ports? This is a connection to a third *party plc.Any help would be great.
 
Each MB Client requires separate Connection ID.
You Can always sequence MB Client calls to save Conn ID :).
 

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