I am having problem communicating 3 PLCs. 2 of the PLCs are configured in PCS7 and the other PLC is configured separately on another database.
I heard using send_bo rcv_bo on the 2 PLCs but how about the other one?

By the way, I am using an old version of PCS7 (v 5.1)..

 

All are siemens s7-400. The two PLC are included in a single PCS7 project while the other is on a separate PCS7 project. The 3 PLCs are connected to an Operator Workstation via ethernet.

I read that a block called TCON/TDISCON can be used on PLCs on different database but I cant seem to locate it in the old PCS7 library. I cant update the library either.

Please help.