(Sheila, Max, Chris)

On Friday we uncovered a snafu with the slow controls cabling at the Y end.  The connector labels engraved on the rear panel of the "End 2" EtherCAT chassis (Exhibit A) do not agree with the chassis wiring plan (Exhibit B).  Upon opening the chassis it appeared that the internal wiring to the Beckhoff modules was done according to (B), whereas the external cable runs had been connected relying on (A).  Here's a table showing the correspondences:

Port
Wiring plan
Rear panel description
6
Auxiliary
DC Photodiodes
7
PZT Mirrors/PDs/Laser Temp
Auxiliary
8
TCS
PZT Mirrors/PDs/Laser Temp
9
RF Amplifiers
TCS
10
DC Photodiodes
RF Amplifiers
11
LSC Demodulators
LSC Demodulators
12
Laser Diagnostics
Laser Diagnostics

This problem came to our attention after we noticed that the fiber PLL slow path (laser temperature) control output was broken.  Actually it was just routed onto the wrong cable.

Attached images show the interior and rear panel of the End 2 chassis at the Y end.