Micrologix 1200 No Output lights

[tomone]

Hi all

Have a Micrologix 1200 (1762-L24BXB)

There are 2 expansion modules attached. 1x 1762-IQ16 and 1x 1762-OB16.

The PLC wired inputs and input card is working. However, there are no outputs lighting up or switching voltage on the PLC wired output or the expansion module outputs.

Outputs in the program are active. This is a controller that was in a working machine that now seems to have failed.

When I came to the PLC There was a major fault in the processor. "The controller cannot communicate with the expansion I/O module. Exact module cannot be determined"

I believe the output module had already been replaced. There replacement was the same as the original. I cleared the fault and now there are no faults showing and the PLC runs fine aside from the issue with no output or output lights activating on the PLC wired output or on the output modules wired outputs.

Any ideas on this problem.

Thanks

 

[controlconcepts]

Not sure this is the case but some output modules need the + and - voltage wired to make the modules lights work and operate.

 

[geniusintraining]

The way I would troubleshoot it would be remove the wires from the cards incase of a short, then check with just a meter to see if I could get voltage at the output

Is the input card first (IQ16) then output (OB) last? maybe swap them but you may have also lost the buss on the IQ16 if its first.

Now that its all looks good (other then no output) does the tree in RSLogix show both cards?

 

[sharkyh2o]

have you returned to run or is the PLC still in program from the fault reset?