corey.gray@LIGO.ORG - posted 16:18, Thursday 01 December 2016 - last comment - 18:11, Thursday 01 December 2016(32069)
Ops Day Shift Summary
TITLE: 12/01 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR: Jim
SHIFT SUMMARY:
Much_Of_Morning Main Issues:
- ETMy 4735Hz Violin Mode Harmonic damping! Upgraded Filter Banks for ETMy & damped out the mode(!)
- HAM3 ISI Saturation & Trips. Hugh noted, addressed, & appear to be better so far.
LOG:
- 16:25(?) HAM3 ISI tripped while in PRMI; this is unusual.
- 16:35-16:55 Down for Guardian Memory Upgrade (WP6366)
- 19:03 Mid-station visit (Karen)
-
21:57 OBSERVING!
- NOTE: Have been getting DIAG_MAIN message about the FAST Shutter
- 22:08 Lockloss, nothing obvious from Seismic or StripTools. It was NOT HAM3ISI.
- Ran Lockloss select which brought up mainly ASC Channels, but I did not see anything obvious.
-
22:39 OBSERVING
- 23:22 Incoming Peruvian EQ, Transitioned EX & EY ISIs to "250_SC_EQ" state
- 23:25 Lockloss
-
0:15 OBSERVING
- Jim ran another A2L with his new medm/script interface before going to Observe.
Locking Notes:
After hand-off this morning, held at VIOLIN_MODE_DAMPING. Kiwamu came in to take a look at H1 & wanted to note a few items he checked.
- ETMy: SUS L3 outputs saturated when trying LOWNOISE_ESD_ETMY: The Suspect was: higher order violin mode harmonic at ~4753Hz.
- For next lockloss attempt, Enabled FM3 for LSC DARM2 & Made it to NLN, then made first damping attempt of 4753 Mode.
-
A2L run, but later received "OMC DCPD Saturdations"
- Jenne: OMC_Lock: REMOVE_WHITENING state & then back to READY_TO_HANDOFF
- Lockloss when trying to take out phase of MODE9....I should have ramped gain down, changed phase, & ramped gain back up.
- HAM3 trip while going up to REDUCE CARM OFFSET
- Spent a few hours damping 4753Hz in DC READOUT (see other's alogs)
A note on the OMC whitening:
The 4.7kHz mode was super rung up, and this was causing the saturations, and a giant comb of upconversion around the line. I turned off the stage of whitening so that we would have a hope of damping anything, which is nearly impossible to do while saturations are happening everywhere. Anyhow, hopefully this won't be a problem anymore since we have found filters that work well for this mode, but any operator can use this trick to save a lock, if a mode is super rung up and needs serious damping.
To remove a stage of whitening, I opened the "all" screen of the OMC_LOCK guardian, and selected RemoveWhiteningStage. Once it starts that state, you can re-select ReadyForHandoff (the nominal state) and it'll return there when it is done. You should see 2 SDF diffs in the OMC, which ensures that you aren't going to Observe with this weird state - it's just for use while damping seriously bad modes.
Young-min and I looked into the 22:08 lockloss that is still unexplained, and attempted to use the BLRMS tool.
The first suspensions to saturate are the ETMY ESD channels, which are saturate at almost exactly the lockloss time. There isn't much in the ASC until after the lockloss, and other than DARM the other LSC loops don't seem to be having trouble.
The first thing that we see happening is a fast glitch in the DCPDs. We don't see anything in CARM signals, OMC PZTs, or ISS, but there is a similar glitch in AS_C_SUM, AS_A, AS_B. I
It is hard to imagine optics moving fast enough to cause this lockloss, but I am not sure what would have caused it.