Displaying report 1-1 of 1.
Reports until 00:29, Thursday 10 October 2024
H1 General (SQZ)
thomas.shaffer@LIGO.ORG - posted 00:29, Thursday 10 October 2024 - last comment - 12:19, Thursday 10 October 2024(80582)
Ops Owl Update

H1 requested assistance around 11pm PT due to the SQZ filter cavity not being able to lock. Based on previous alogs, it sounds like there was some SQZ issues earlier today, but there's no mention as to what exactly. Looking at the FC green camera it was clearly trying to lock with a pitch misalingment, so I adjusted FC2 and maximized H1:SQZ-FC_TRANS_C_LF_OUTPUT. This seemed to help, but then after it would find IR it would lose lock. I'm not sure why, but we just lost lock (0720UTC) so I guess I'll see if it happens again when we get back.

Comments related to this report
thomas.shaffer@LIGO.ORG - 02:27, Thursday 10 October 2024 (80583)
Link

Relocking was automatic but again the SQZ FC couldn't tranistion to IR. Vicky came to rescue and was able to get it working. Something I should have seen earlier is that there was a dolphin crash, so the ZMs were way off from their nominal position. Notes from Vicky:

  • Adjusted OPO TEMP
  • TJ manually aligned FC2 P to get FC green to lock
  • I lowered FC ASC threshold for FC-IR ASC to trigger ON (lowered from 0.3 to 0.2 to get FC-ASC triggered. Then set it back to 0.3 when it engaged)
  • Ran SCAN_ALIGNMENT_FDS twice. Since FC alignment caused SQZ ASC alignment to be way too far off (>100slider counts) , SQZ ASC did not work at first after running FC ASC.
  • after 2x SCAN_ALIGNMENT, SQZ ASC worked, left it here, went to observe

Accepted SDFs for SQZ ZMs/FC2 and LSC-LOCKIN_OSC_FREQ

Images attached to this comment
camilla.compton@LIGO.ORG - 12:19, Thursday 10 October 2024 (80590)OpsInfo, SQZ
Link

Sheila, Camilla

Trending back what happened last night:

  • First t-cursor: dolphin crash, FC1,2 OSEMS move when computers come back but ZM1,2,3,4,4,5,6, don't plot.
  • Second t-cursor: Ibrahim and Sheila and then separately Ibrahim and Daniel moved ZM FC2 back after the crash to allow FC to lock. Squeezing wasn't yet injected when we lost lock plot.
  • During this lock when the FC was struggling to lock, SQZ ASC came on and moved ZM4/6 the wrong way....
  • Once we lost lock FC1 and FC2 sliders were reverted by sdf.
  • Vicky and TJ then had to move FC1/2 and ZM4,5,6 to get squeezing injected in the IFO.

To avoid this in future:

  1. Currently in SQZ_MANAGERthe state SQZ_ASC_FDS is before FC_WAIT_FDS. We don't want the SQZ IFO ASC to turn on until the FC is locked or it will pull ZM4/6 to an incorrect place. I've swapped the order of these and reloaded SQZ_MANAGER. I changed the state number of FC_WAIT_FDS from 90 to 64 so that states are still numerically in order.
  2. ZM1,2,3,4,5,6, FC1,2 are now not monitored by sdf.

Tagging OpsInfo: if you run SCAN_SQZ_ALIGN and don't like it, you'll need to trend back ZM4/6 optical align sliders as they aren't in sdf. Also you need to turn off SQZ ASC before running scan_sqz_alignment, updated instructions in wiki.  <- added this the the guardian.

While looking at this we also decided to remove SQZ_FC state LOCKED (nominal is IR_LOCKED we don't see a need for a state that can be GREEN_LOCKED or IR_LOCKED).

Images attached to this comment
Displaying report 1-1 of 1.