Reports until 04:39, Saturday 08 February 2020
H1 SUS
cheryl.vorvick@LIGO.ORG - posted 04:39, Saturday 08 February 2020 (54978)
relocking driving some violins, damping with lower gains
  1. TJ asked me to look into PI modes causing the fast lockloss, and I've been watching the violins ring up as H1 tries to relock, and tonight ETMY mode 1 was clearly being driven, as seen in the increase of  the drive.  The first attachment shows 3 unsuccessfil relock and then a 4th lock aquisition,.  The first 3 end in locloss, not necessarily due to violins, but looking at the increase of the amplitude of the drive on this mode, it's being driven with greater amplitude for each relock.  Other modes have the same feature.  The last attachment shows the peak growing.

 

Date UTC Time RMSLP_LOG10 Drive Output
    seconds top of first bounce +/- envelope
         
7 Feb 2020 22:35 UTC T = 0 2 0.009
7 Feb 2020 23:17 UTC T = 2561 4.32 3.4
7 Feb 2020 23:47 UTC T = 4336 4.92 9.8
7 Feb 2020 00:51 UTC T = 8197 5.02 13.4
8 Feb 2020 01:13 UTC T = 9500 5.21 21

 

  1. I looked at the drives for the high gain modes from multiple attempts at relock
    1. IX mode 11, gain = 600
    2. IY mode 14, gain = 500
    3. EY mode 17, gain = 200
    4. EX mode 15, gain = 1500
  2. reduced gains
  3. as soon as I started reducing the high gains, other modes damped with their current gains
  4. damped the high gain modes damped with  values below, others gains reduced if possible
    1. IX mode 11, gain = 10
    2. IY mode 14, gain = 5
    3. EY mode 17, gain = 50 (could likely go lower)
    4. EX mode 15, gain = 10
  5. Then I restored all the nominal damping
Images attached to this report