iX Talk

Hello,

Normally I used S7-1200 and Iso over TCP, now customer wants to have S7-300

As I understood I need to use MPI comms, but which one to select:
- S7 MPI direct
- S7 MPI Hmi adapter

I have found old Siemens USB/MPI converter and started testing.
Physically I can see 1 COM port and 1 USB port.
Under Ix Developer/System I see 3 ports
- COM 1 RS232
- COM 2 RS422/485
- COM 3 RS485

I have sellected S7 MPI direct, COM2 RS485 and try to get it working just by reading IW0.
I get "Comm stn error". In case with 1200 I would need to permit communication in PLC properties, but in case of S7-300 I have nothing to do. I do not get any MPI bus warnings in Siemens and can not read any data.

After a while I have tried all ports and have no result.

Does anyone knows proper setup for fixing this issue?

Thank you!

Hi frzw,
I first would ask you to verify the COM port wiring. Your comment about seeing only one physical port is something that causes a lot of confusion. Even though we only have 1 DB9 it facilitates 3 Com ports on differing wires. For example, RS232 uses pins 2rx,3tx,and 5gnd. For a complete list of wiring pins please refer to the help file found in iX by going to "Tags"-"Controllers"-"Settings"-"Help". Look under the connecting to the controller section found in each driver.