nutsinee.kijbunchoo@LIGO.ORG - posted 00:11, Sunday 23 October 2016 - last comment - 14:21, Sunday 23 October 2016(30756)
Ops EVE shift summary
TITLE: 10/22 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: Patrick
SHIFT SUMMARY:
- ITMY bounce mode has been a bit of a problem so watch out and be ready to flip the sign of the gain (Guardian turns on 0.1, this seems to be ringing up the mode). I'm not sure where would be the best place to put this in the Guardian so it will have to be done by hand for now.
- PI Mode 28 came on once and changing phase didn't make a different to Terra made a new filter for it (the frequency of the mode has moved far from the existing BP filter).
- During the night we lost lock at PREP_TR_CARM. The state appears to be putting too much of an offset to both LSC-TR_X and Y QPD and the IFO never find IR again until the offset was put back. If you have Check IR problem and LSC-TR_X (and Y)_NORM appears to be flashing at negative values, check LSC_TR_X(and Y)_QPD_B_SUM_OFFSET. If it's negative trend it back to when it was still good. Then caput that value back to the channel(s).
- DRMI locking -- When locking DRMI, increase LSC PRCL2 gain by a factor of 2 (original gain is 1, so make it 2). Once the DRMI is locked lower it back to 1. Worked twice. I assume this works for PRMI as well if the flashing appears to be good but the loop won't catch lock. Thanks Stefan for the trick.
- Soon as the clock turned midnight I got a verbal alarm telling me there's a new remote user. There's no name. Just "root". Root only logged on for less than a minute or so and left. Is it an interferometer ghost?
I would recomend that instead of putting the extra factor of 2 gain in PRCL2, people double the gain in PRCL 1. The guardian doesn't touch the gain in PRCL2, but it will later in the locking sequence adjsut PRCL1 to be the nominal value. If people adjust the gain in PRCL2 and forget to rest it to 1, this can cause problems.
If we consistently are needing higher gain, there is a parameter in LSC params that adjusts the gains for lock acquisition.