hi 

I have 1200 PLC using modbus tcp client block to read data from 3 power meters.

I am trying to configure Connection properly - Am i right thinking that my interface ID will be the same for 3 connection instances but connection id will be dfiferent eg. 1,2 or 3?

Regards

Hi. 

It depends if you are using same hw interface to communicate to modbus partners the "InterfaceID" should be the same, if you are using for example for 1 partner the cpu network port and for other a CP module, the "InterfaceID" should be different.

For connection ID it is an unique number to identify the connection.

see attached manual on pag. 25

Regards.