camilla.compton@LIGO.ORG - posted 20:20, Thursday 01 June 2023 - last comment - 22:32, Thursday 01 June 2023(70076)
SHG will relock if SHG PZT voltage outside 15 to 85V before we are squeezing
SHG PZT has 0-100V range, in alog 69366 we added a checker in LOCK_SHG and SQZ_READY_IFO to check if H1:SQZ-SHG_PZT_VOLTS is getting too low and relock near the middle of it's range.
We've now been seeing it get very high and it ran out of range 2 days ago, see attached. I adjusted the checker if take SQZ_SHG guardian to DOWN also if H1:SQZ-SHG_PZT_VOLTS > 85.
SQZ_MANGER needs to be reloaded when the IFO is DOWN.
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SHG PZT ran out of range at 04:57UTC and I reloaded the SQZ_MANAGER guardian while it was relocking so this shouldn't happen again. It relocked at 56V (~middle of range).
Strange relocating behaviors:
- The beam diverter didn't close when we dropped to LOCK_SHG, I added the turn_of_sqz() line to this state as we did to others in 69724, now I really have checked all the jump states. SQZ_MANAGER will need to be reloaded.
- The filter cavity failed to lock green ~4 times before successfully locking itself, unsure why but I have attached the plot.
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