I am having a s7-400 system CPU 414-3 DP with expansion racks.Interface modules used are IM-460-0 with two IM461-0.

I have analog input modules connected in both CPU and IM's. But after getting system online most of the modules are giving me values like 7FFFh (Overflow). I tried and shifted modules to slots which are working and I found all those modules are working for those slots. I must mention you that plant is working for last 6 to 7 years. I also replaced connectors of module but same problem repeated. I also replaced old modules with new one but found same problem.

I am here to find this issue. But I am not getting how all modules are not showing values at the same time? Can there be problem in bus connectors mounted on rack behind Analog input modules? Please clarify me this issue..

Thanks,

Shailesh

I have checked configuration online and I didn't found any fault. As I mentioned I interchanged the modules for the same slot. The modules are same. Here are some images which have attched. Please go through it.

I found some of the modules configured as 4 wire [C] in hardware configuration and physically on module set as 2 wire [D]. Bur I'm not getting any fault on that module. Transmitters connected to channels of module are 2-wire. Does it cause modules or back connectors to malfunction?

I'll check by changing hardware configuration today and will give you reply.

Thanks,

Shailesh