ryan.crouch@LIGO.ORG - posted 07:34, Tuesday 29 July 2025 - last comment - 10:34, Tuesday 29 July 2025(86050)
OPS Tuesday day shift start
TITLE: 07/29 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 0mph Gusts, 0mph 3min avg
Primary useism: 0.01 μm/s
Secondary useism: 0.05 μm/s
QUICK SUMMARY:
- We've been locked for almost 9 hours
- Magnetic injections are running, to be followed by SUS charge
- Lots of maintenance tasks on the docket today
When the SUS_CHARGE was finishing up and SWAPPING_BACK_TO_ETMX ETMX L3 started to constantly saturate and there was a big line on DARM at ~150. This behavior persisted even after the GRD was done and went back to waiting. (tagging SUS).
15:02 UTC I induced a lockloss at by flipping the polarity of H1:IMC-REFL_SERVO_IN1POL, to break the lock and to stop the EX saturations.
I took a look at why there were saturations, and I think it's because of our changes yesterday. When the measurement finished, the ETMX bias was reverted to the new value that Sheila and I used yesterday, but the L3 drivealign gain was set to the old value of 198 instead of the new value of 88. I looked at the script and I don't understand exactly how that happened since it appears that it pulls the values right from LSCparams, but the ndscope I attached shows this is what happened.
I think this was due to the fact that the SUS_CHARGE GRD was not reloaded after lscparams was changed, I've reloaded the GRD.