H1 was dropped out of OBSERVING due to the TCS ITMy CO2 laser unlocking at 0118utc. The TCS_ITMY_CO2 guardian relocked the 2min.
It was hard to see the reason why at first (there were no SDF Diffs, but eventually saw a User Message via GRD IFO (on Ops Overview) pointing to something wrong with TCS_ITMY_CO2. Oli was also here and they mentioned seeing this, along with Camilla, on Oct9th (alog)---this was the known issue of the TCSy laser nearing the end of its life. It was replaced a few weeks later on Oct22nd (alog).
Here are some of the lines from the LOG:
2024-11-13_19:43:31.583249Z TCS_ITMY_CO2 executing state: LASER_UP (10)
2024-11-14_01:18:56.880404Z TCS_ITMY_CO2 [LASER_UP.run] laser unlocked. jumping to find new locking point
.
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2024-11-14_01:20:12.130794Z TCS_ITMY_CO2 [RESET_PZT_VOLTAGE.run] ezca: H1:TCS-ITMY_CO2_PZT_SET_POINT_OFFSET => 35.109375
2024-11-14_01:20:12.196990Z TCS_ITMY_CO2 [RESET_PZT_VOLTAGE.run] ezca: H1:TCS-ITMY_CO2_PZT_SET_POINT_OFFSET => 35.0
2024-11-14_01:20:12.297890Z TCS_ITMY_CO2 [RESET_PZT_VOLTAGE.run] timer['wait'] done
2024-11-14_01:20:12.379861Z TCS_ITMY_CO2 EDGE: RESET_PZT_VOLTAGE->ENGAGE_CHILLER_SERVO
2024-11-14_01:20:12.379861Z TCS_ITMY_CO2 calculating path: ENGAGE_CHILLER_SERVO->LASER_UP
2024-11-14_01:20:12.379861Z TCS_ITMY_CO2 new target: LASER_UP
CO2Y has only unlocked/relocked once since we power cycled the chassis on Thursday 14th (t-cursor in attached plot).
0142: ~30min later had another OBSERVING-drop due to CO2y laser unlock.
While it is normal for the CO2 lasers to unlock from time to time, whether it's from running out of range of their PZT or just generically losing lock, this is happening more frequently than normal. The PZT doesn't seem to be running out of range, but it does seem to be running away for some reason. Looking back, it's unlocking itself ~2 times a day, but we haven't noticed since we haven't had a locked IFO for long enough lately.
We aren't really sure why this would be the case, chiller and laser signals all look as they usually do. Just to try the classic "turn it off and on again", Camilla went out to the LVEA and power cycled the control chassis. We'll keep an eye on it today and if it happens again, and we have the time to look further into it, we'll see what else we can do.