F. Clara, K. Kawabe, M. Pirello
We checked the following for ground loops:
CER:
Beam Diverter Cables - Both tested good.
From SUS R1:
JM1 is good
JM2 is good
JM3 is good
PM1 - Pin 2 is grounded, Shield is not connected to pin 13 (cable HAM1_311)
RM1 - Shield is not connected to pin 13 (cable HAM1_228)
RM2 is good
From ISC Racks:
ISC_222 (db9) pin 5 not tied to shield, signals good
ISC_221 (db9) pin 5 not tied to shield, signals good
ISC_226 (db9) pin 5 not tied to shield, signals good
ISC_356 (db25) pin 13 IS tied to shield, signals good
ISC_223 (db25) pin 13 not tied to shield, signals good (older cable)
ISC_224 (db25) pin 13 not tied to shield, signals good (older cable)
ISC_225 (db25) pin 13 tied to shield, signals good (new cable)
ISC_227 (db25) pin 13 tied to shield, signals good (new cable)
EOM RF Signals:
At Rack, all RF signals shields are tied to rack ground.
Cable runs are isolated from rack and chamber ground
At Chamber, all RF signal shields are tied together in chamber possibly at EOM.
IOT2 Table Enclosure:
Picomotor Cable - pin 13 tied to shield, signals good.
All EOM RF shields are tied together on the metal part of the EOM by design, but the EOM is isolated from the chamber.
We (Marc and me) confirmed that EOM RF shields are isolated from the chamber ground.
Fil informed me that pin 13 and shield of the picomotor driver cable at IOT2 are both tied to chamber ground. This is cable ISC_227 from HAM1 to IOT2.
https://dcc.ligo.org/LIGO-D1900511 version 12
IOT2 layout pages 16&17
HAM1 flange layout page 24
We can mitigate this at the picomotor driver end, just making a note of it here.