patrick.thomas@LIGO.ORG - posted 00:00, Saturday 02 November 2019 - last comment - 12:50, Tuesday 05 November 2019(52913)
Ops Eve Shift Summary
TITLE: 11/01 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC STATE of H1: Observing at 113Mpc INCOMING OPERATOR: Jeff SHIFT SUMMARY: One lock loss, no immediately apparent cause. Only required intervention was to adjust ETMX, TMSX and ETMY for LOCKING_ARMS_GREEN. LOG: 23:37 UTC Kyle, Robert, Chandra to LVEA to adjust pressure on gate valves 23:40 UTC Dropped out of observing. Changed observatory mode to preventative maintenance. 23:44 UTC Sheila and Keita changing FSS fast gain 00:07 UTC Robert, Chandra back 00:12 UTC Back to observing 00:46 UTC Lock loss Waited for 5 minutes for green arms to lock. Neither arm locked on its own. Flashes are around .4. Set both arms to UNLOCKED. Moved ETMX and TMSX. The starting values were: ETMX: 64.4 P, -132.5 Y TMSX: -84.2 P, -50.6 Y I lost the ending values when I set the arm to ETM_TMS_WFS_OFFLOADED. Moved only ETMY: 130.5 P. -136.7 Y -> 132.1 P, -137.1 Y Set Y arm to ETM_TMS_WFS_OFFLOADED. Both arms locked. FIND_IR appears to be failing, taking a really long time with no flashes. Lock loss waiting for FIND_IR Both arms locked on green on their own FIND_IR worked this time Green arms still appear locked even after going through ARMS_OFF_RESONANCE. Can't remember if that is normal. DRMI failed and it automatically went to PRMI. PRMI locked very poorly, but ASC fixed it. DRMI locked. 06:10 UTC NLN 06:13 UTC Observing
I'm just following up on what patrick logged here about th eneed to intervene in x arm alignment. I think that there is probably a typo above and the lockloss that Patrick is talking about is at 4:46 UTC.
Starts at the time of the lockloss (ALS_XARM state goes from 100 (shuttered) to the various locking states). You can see that the optics get kicked when the ASC control signals turn off, and that this is a DC alignment shift for them, bringing the arm closer to the alignment at which it can lock.
The changes from the free swining alignment after the lock to the alignment after the arm is locked and WFS engaged:
+1.4
The sliders are in pretty good agreement with the witness sensors about these shifts. I've added the ndscope that I used to make this, and a similar one for the Y arm, to the ALS overview screen, to help make it easier for operators to find and report this kind of information.