corey.gray@LIGO.ORG - posted 17:45, Monday 29 September 2025 - last comment - 08:36, Tuesday 30 September 2025(87207)
SQZ Drops H1 From Observing For About 11min
At the top of the hour (within 15seconds), the Squeezer unlocked and took H1 down. Tony was in here and thought the timing was odd with it happening close to the top of the hour! (he saw that the PMC went down at 00:00:15).
The Log for the SQZ MANAGER also notes the PMC as the cause (w/ a message of "LO railing!").
I slowly got SQZ windows opened & got the wiki up and started recovery by Steps:
- #1: Taking the SQZ MANAGER to DOWN. Everything came back
- #2: Bringing back SQZ_PMC, SQZ_SHG, SQZ_OPO_LR and then SQZ_CLF_LR nodes all to their NOMINAL states
- #3: This step is where I got a little confused. The instructions say to take the FC node to GR_LOCKED (got there w/ no problem). But then the instructions say: "Trend H1:SQZ-FC_TRANS_C_LF_OUTPUT, if it's peaks are less than 100, follow instructions in below "Issues with SQZ_FC Guardian""."
- Well, for me, this channel "flat-lined" at about 45-46 counts for GR_LOCKED (I did not see peaks), and this channel has been like this (under 100) for weeks (see attached).
- So, I opted to NOT follow the Steps for Issues with SQZ_FC Guardian, and at this point, I just took the SQZ MANAGER to FREQ_DEP_SQZ, and this got squeezing & observing back.
Images attached to this report
Comments related to this report
Reason for SQZ unlock was PMC PZT getting to the end of it's range at 0V.
The FC Trans level in the wiki was a red herring (has been corrected), we're unsure why it has dropped so much in the past few months, plot.
Images attached to this comment
