jim.warner@LIGO.ORG - posted 14:28, Thursday 23 May 2019 - last comment - 17:04, Thursday 23 May 2019(49414)
IMC MCL sdf diffs suspicious timing
Just had some unexplained sdf diffs show up after the last re-locking. 2 trigger thresholds in IMC MCL, which were changed about the time of the last lock loss, which did not have an obvious cause. No idea if these are relevant or what caused the change.
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I think these are triggers for turning on the IMC MCL boost. They're set in the IMC_LOCK down state, and the thresholds are set depending on the input power into the IMC. For some reason we're stuck with the 2W trigger thresholds, probably when we lock again we'll have another SDF difference undoing this.
I don't think this is a problem, or related to our locklosses, since the IMC is controlled by LSC-MCL (not IMC-MCL) for everything after the LOCKING_ALS state.