brina.martinez@LIGO.ORG - posted 14:29, Tuesday 13 June 2023 - last comment - 17:25, Tuesday 13 June 2023(70423)
re-engaged 4:1 Hz MICH1 FM3 filter
Brina, Sheila,
After taking a look at the UGF for the Michelson loop, we turned back on the 4:1 FM3 filter on 06/13/23 at 21:17:50 UTC and will run it for at least a week to see if this aids in keeping lock from Earthquakes, (alog 70293 thread).
The original filter was in MICH2 FM3 (see 68432) (which is the same as what Brina and I edited MICH1 FM3 to be this morning), and was engaged in the DRMI guardian. I've edited and loaded the DRMI guardian to engage this again, so next time we relock this should be on.
This gets turned off when the IFO unlocks (in sdf revert). To keep this filter on in Observing, the operator should REVERT the lsc model sdf diff for MICH1 FM3 (turning FM3 on) to get into observing.
To get around this we could decide to keep this on during locking or editing the guardian.