Patrick and Sheila-

After the fiber swap today, Cheryl pointed out that the beckhoff channels were not working,  the epics channels had values but weren't updating.  

I looked at the PLC in the h1ecatc1 machine, PLC1 was running ( and values were updating) but in PLC2 nothing was updating.  I tried reset all, and then hit run, and the values would update once each time I did that.  I tried stopping the PLC and rerunning the installation scripts, then I tried restarting the computer, the behavior was the same after that.  

Then Patrick took over-

The short version: This seemed to be caused by losing communication to the end Y chassis. The communication was lost because after the fiber cleaning the transmit and receive fiber pairs for this connection were swapped. I have no idea why losing communication to the end Y chassis would stop the values updating in PLC2.

The slightly longer version: Looking at the H1ECATC1 system manager file, there was no communication with the end Y chassis. When I disabled the terminal for this connection, I could get the values to update in PLC2. Later Dave B. swapped the transmit and receive fiber pairs at the end Y EK1521-0010 terminal inside the H1 Corner MSR chassis. I then reenabled this terminal in the system manager and the communication was restored. The PLC2 variables also continued to work. Dave confirmed that the connection inside the chassis did not match our standard and swapped the transmit and receive pairs for end X as well.