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Reports until 17:50, Thursday 21 February 2019
H1 ISC
jenne.driggers@LIGO.ORG - posted 17:50, Thursday 21 February 2019 - last comment - 08:48, Friday 22 February 2019(47063)
EZCA connection errors in just the wrong place causing locklosses today

[Jenne, Georgia, Sheila, Craig, Dan, Danny]

We've lost lock a few times today while trying to increase the power, so that we can try the new DARM loop scheme (crossover shaping) that Sheila has cooked up.  It turns out that the problem was an ezca connection error in the main part of the INCREASE_POWER guardian state, causing the ISC_LOCK guardian to freeze while trying to reconnect.  However, before the error, ISC_LOCK guardian has already requested the laser power guardian to increase the laser power, which it starts to do.  But then, since ISC_LOCK guardian is frozen, the DARM fringe offset is not being adjusted to match, and we lose lock.

Happily, the ezca commands that were causing trouble were setting the RPC filter states, but they don't actually need to be in the guardian at all, since we don't ever change them.  So, they are now removed from that state, and we're almost ready to try increasing the power again.

Comments related to this report
jeffrey.kissel@LIGO.ORG - 08:48, Friday 22 February 2019 (47074)CDS, GRD
This is another instance of the bug reported in FRS Ticket 12067. Not sure what other documentation exists on this (I feel like much more progress has been made, but not reported in *that* ticket).
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