At 5:13 UTC it unlocked for no obvious reasons; in the relock phase the ITF unlocked during the locking of the OMCs and, as happened many times in the last days, the WE LC were open by the guardian at 5:36 UTC.
I was able to properly close the loop and to restart the lock acquisition at 5:51 UTC.
Finally at 6:25 UTC the ITF was back in Science mode.
At 12:25 UTC under request of Annalisa we made an Adjusting break to try to minimize the SSFS correction but unfortunately the ITF unlocked in the meantime; no actions were ongoing at the moment of unlock.
ITF relock in progress...
ISYS
an oscillation is well visible on the IMC_ref camera; Antonino is investigating the problem...
DAQ
- from 8:30 UTC to 8:33 UTC the DMS reported a red flag for:"rtpc6 - Loop cycle troubles"; in this time window we had missing data and from SPRB and Hrec_Range_BNS not computed.
- InjMoni restarted at 12:24 UTC to take into account new configuration.
SBE
SNEB LC TX set point adjusted at 6:24 UTC (SNEB_B7_Cam1_FitPosY yellow flag on DMS), see attached plot.
SUSP
DMS yellow flag for PR_Vert - Sa_PR_F0_COIL_V2; experts have been informed.
DetChar
lvalert_virgo restarted at 7:26 UTC after a crash.
Pending
perform Longitudinal Noise Injection in addition to the planned calibrations
"At 12:25 UTC under request of Annalisa we made an Adjusting break to try to minimize the SSFS correction but unfortunately the ITF unlocked in the meantime; no actions were ongoing at the moment of unlock."
Next time, please contact the run coordinator before taking actions.
Of course it's true, the run coordinator must be contacted before.
However, the action was not planned in advance and instead moved by some "emergency" situation: the fact that the interferometer was suffering a pathological situation, i.e. SSFS_Correction very high (figure 1) and arising of the line at 273Hz in Hrec (figure 2) which in the past brought to saturation of the SSFS correction and therefore to an unlock (#45992). All this was witnessed by a very striking oscillation of the IMC reflection.
Given the situation, I tried to adjust the SSFS gain (and for this asked a suitable status of the ITF). However, the unlock seems to be unrelated to the undertaken actions, as shown in figure 3 and 4, which is a zoom, where the B1 power goes up while SSFS correction doesn't show any change.
Investigations are ongoing to understand the origin of this issue.
