camilla.compton@LIGO.ORG - posted 15:50, Tuesday 14 January 2025 - last comment - 17:26, Tuesday 14 January 2025(82277)
Re-added DARM boost that was removed because of glitch after CDS filter ramping changes
In 81638 we removed a DARM1 FM1 boost because of a glitch when ramping it off causing locklosses during ESD transitions in preparation to switch back to ETMX. Today the CDS team updated H1OMC0 models with an improved filter ramping: 82263. We hope this will allow us to keep the boost us which gives us more range against high microseism while relocking (it's always off by NLN).
Uncommented line 3058 from ISC_LOCK.py and reloaded: ezca.get_LIGOFilter('LSC-DARM1').turn_on('FM1'). If we have locklossses at ISC_LOCK state 557 or 558, at the operator can re-comment this line out. Tagging OpsInfo.
Sheila, Camilla, Erik
We lost lock 12s after this DARM1 FM1 filter was turned off, we're not sure if the filter changes are the cause. Are trying to relock again.
We think we were a little confused and have been turning on FM1 the whole time, as it was still turning on in PREP_DC_READOUT_TRANSITION. Unsure if it was just luck that the glitch disappeared when we made the change Dec 5th. Will look into more...
Re-commented out line 3058 today at 1:25 UTC after losing lock at the same state LOWNOISE_ESD_ETMX (558).