PLC-009 - Different Function Code Received From PLC

[rguimond]

Started receiving this error on some of the C-More HMIs that are part of the plant network. There does not seem to be any issues with functionality.

No PLC programs were changed.

Only three of about 32 PLCs on the Ethernet network are creating the errors. Once is a Micrologix 1100 and the other two are SLC 5/05. They are connected to the HMIs via an unmanaged switch, which was changed

Rebooting the entire network didn't help.

I went through all of the PLC programs to ensure there were no tags that referenced addresses not present in the PLC programs and didn't find any

All devices can be pinged fine, with no time-outs

Any suggestions?

 

[AutoMax]

Press the upper left corner of the Cmore for ten seconds, say Yes you want the System Screen and go to the Information button. Once in the Information section, go to the error tab and it should give you a bit more information.

(Stolen from Automation Direct Customer Service)

 

[rguimond]

Actually, it seems the issue is related to ping timeout. I just didn't let the ping tests run long enough.

Haven't had much time to troubleshoot today, except for moving the cables from the affected PLCs to different ports on the switch, which made no difference.

 

[rguimond]

Solved!

The problem ended up being a fiber cable connecting two switches. I didn't replace the cable - I just replaced it with an ethernet cable and the problem went away