keita.kawabe@LIGO.ORG - posted 17:35, Saturday 08 October 2016 - last comment - 09:41, Monday 10 October 2016(30335)
What happend to PMC?
Something happened early in the morning today (about 2016-10-08 12:50 UTC +- 10 min) and the transmission is only 78W as of now while the reflection is 38W or so.
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It looks like the ISS diffracted power jumped up at the lockloss. I started changing the H1:PSL-ISS_REFSIGNAL to bring it back, but then trended it and saw it hadn't changed, so put it back.
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- PMC TRANS drops from 97W to 78W
- ISS QPDX shifts alignment from 0.0068 to 0.0047
- ISS QPDY starts to drift
- ISS PD NORM drops from 0.862 to 0.679
- FSS TPD DC drops from 3.58 to 2.86
- plot attached
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- NOT SURE WHAT THIS MEANS:
- DBB signals seem to be changing in power, if they're calibrated, by about 1.5V. The plot I've attached shows this after the PMC power goes down, but in reality the DBB signals were changing like before the power drop.
- plot 1 PMC trans power drops
- plot 2 DBB signals changing before the power drop
- plot 3 DBB signals changing after the power drop
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More about changes in PMCsignals at lock loss: PMC Trans drops, FSS and ISS increase in power
- PMC Trans drops ~ 19W
- PMC REFL doesn't change
- FSS RFPD jumps up from 0.023 to 0.055
- ISS QPDX drops from 0.0068 to 0.0047
- ISS QPDY begins to drift
- ISS Difraction jumps up from 4% to 9%
- ISS second loop sum drops from 2.45 to 2.17
- MC2 Trans Sum drops from 155 to 123
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