Hello Everyone,

I have to configure a Modbus TCP data exchange from a S7-1516-3 PN/DP CPU with an external DCS system.

The modbus connection is NOT linked directly to the CPU but  pass through a CM 1542-1 communication module.
I've started by testing the code implementation in my project with a local PC, since the real connection won't be available until the plant commissioning.

I've followed the instructions/example from this entry:

https://support.industry.siemens.com/cs/document/102020340/how-do-you-program-and-parameterize-modbus-tcp-communication-between-s7-1500-cpus-and-s7-1200-cpus-?dti=0&lc=en-WW

The PLC is configured as slave/server and I used a master/client application on the PC, however i couldn't get a connection.

So I got back to the Siemens example and tried to establish a connection between my 1500 CPU and a 1200 CPU (1215C DC/DC/Rly) which fortunately I had available.

So the 1500 remains slave/server and I implemented the master/client in the 1200 CPU. Again I could't establish the connection. Both the client and server have status = 7002, which I understood stands for 'partner not connected', with error=false.

I uploaded the connection parameters and the function calls as attachment.

The interfaceID of the server is the HW identifier of the CM 1542 module and the IP address of the client is the address of the CM module.

Additional Info:

-Programming tool: TIA Portal v14 SP1

-PLCs are not connected directly but through a router

-S7-1500 and S7-1200 are developed in different projects

-Every device in the subnet (S7-1500, 1200, CM) can be reached via ping command

Does anyone see the reason why the CPUs are not connecting?
Thank You in advance,

Eugenio Canciani.