TITLE: 09/28 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY:

Currently relocking and at ACQUIRE_DRMI_1F. We were cleared to go into Observing by the CAL team 45 minutes ago when we were still Locked and got in 10 minutes of Observation time before losing lock from an FSS oscillation.
Before that, troubleshooting was being done by the calibration team for the entirety of my shift, so I had just been trying to keep us locked and by running broadband measurements when they needed them. Current status of the calibration work is that they tried multiple things with ultimately no success. The things they tried have been reverted, and they will be writing up their own alog and continuing work on Monday.

While trying to relock after the first lockloss of my shift and this last lockloss, we got stuck in READY due to IMC_LOCK being in FAULT with the DIAG_MAIN messages: "PSL_FSS: PZT MON is high, may be oscillating" and "PSL_FSS_TPD: RefCav transmission low, fix alignment". I tried taking the IMC to DOWN and then back to LOCKED and tried toggling the FSS loop automation OFF and then back ON, but neither seemed to help. But both times the IMC was eventually able to lock, but I'm not sure that it had anything to do with my toggling. Once the IMC was locked, relocking went smoothly for that first relock and so far is going well this relock.
So the FSS oscillations are not only causing locklosses, but now are also starting to delay relocking. Tagging ISC

LOG:

22:16UTC Lockloss
    22:19 Lockloss from LOCKING_ARMS_GREEN
    22:20 Lockloss from LOCKING_ARMS_GREEN
    22:21 Lockloss from LOCKING_ARMS_GREEN
    IMC in FAULT with the messages "PSL_FSS: PZT MON is high, may be oscillating" and "PSL_FSS_TPD: RefCav transmission low, fix alignment"
        - Taking IMC_LOCK to DOWN+INIT and then back to LOCKED didn't work
        - Toggled FSS loop automation autolock OFF/ON, eventually IMC locked a couple minutes after doing this so not sure if it helped
23:29 NOMINAL_LOW_NOISE

23:29 NLN_CAL_MEAS
23:30 Started broadband calibration measurement
23:36 measurement done (PCALY2DARM_BB_20240927T233009Z.xml), back to NOMINAL_LOW_NOISE
23:41 NLN_CAL_MEAS
23:42 Started broadband calibratoin measurement #2
23:48 Measurement done, (PCALY2DARM_BB_20240927T234226Z.xml) back to NOMINAL_LOW_NOISE

00:11 Lockloss
    00:34 Started an initial alignment
    00:52 Initial alignment done, relocking
01:37 NOMINAL_LOW_NOISE

01:43 NLN_CAL_MEAS
    01:44 Started broadband calibration measurement #3
    01:50 measurements done (PCALY2DARM_BB_20240928T014428Z.xml)
01:50 NOMINAL_LOW_NOISE
03:00 NLN_CAL_MEAS
    03:01 Started broadband calibration measurement
    03:08 Measurement done, back to NOMINAL_LOW_NOISE
03:08 Lockloss due to earthquake https://ldas-jobs.ligo-wa.caltech.edu/~lockloss/index.cgi/event/1411528136
04:05 NOMINAL_LOW_NOISE    
04:16 Observing

04:22 Lockloss due to FSS oscillation starting 30 before LL
    FSS oscillating and won't lock - same DIAG_MAIN messages as earlier
    04:39 Got it locked, starting an initial alignment
    04:56 Initial alignment done, relocking