Pegaia

Hi,

Here there are a sample project and some tips for implementation of MODBUS TCP with S7-1200:

1 - Pre requisites: STEP 7 >= V11 SP1 and S7-1200 FW >=2.1

2 – Documentation: the help on line of the blocksMB_SERVER and MB_CLIENTare the best way to get information about these blocks.

3 – Programming:

3.1 – On MODBUS TCP server

Use MB_SERVER instruction on the server:

Ports: as default you can use 502, however it is possible to use any ELSE ports already
used by S7-1200 (20, 21, 25, 80, 102, 123, 5001, 34962, 34963 and 34964).

Each connection needs a block call (with different instance DB, ID and port)

3.2 – On MODBUS TCP client:

Use MB_CLIENT instruction on the client:

Each connection need a block call (with different instance DB). ID and port must match with the server).

4- Status 7002 = meaning that there is no client connected.
Attachment:MODBUSTCP.zip (112 Downloads)

psbinh

thanks mr Pegaia
I readed your sample, but please guide me:
- how a MB_Server block read/write data to a Client?
(because, there are not a parameter which specify a function (ex: 03 or 06...) in MB_Server.
It's difficult for me to understand MB_Server. If in MB_client the combination of the parameters MB_MODE and MB_DATA_ADDR defines a FUNCTION in the mesage... thus how in MB_Server ????

- please help me!
very thanks!