- Patrick, Cheryl, Jeff, Kiwamu
Morning spent with Patrick and I investigating IMC poor locking, i.e. only brief locks. Keita started us on the issues of too much gain on H1:SUS-MC2_M2_LOCK_L_GAIN, which he changed form 0.2 to 0.008, in order to get any locking last night.
Looked at Stefan's autolock script and the channels it changes, and all was OK. Compared MC Common Mode channels/settings, all was OK.
Tracing the GAIN path backward, I found we could lock with autolocker settings and MC2_M2_LOCK_L_GAIN at 0.2, if I lowered the overall MC2 LSC gain from 1.0 to 0.15.
Jeff joined us, we burt restored h1lscepics and MAGICALLY the IMC locked with the MC2 LSC gain back at 1.0! Somehow that fixed the gain issue, though we have not located the exact setting that changed.
At this point Jeff reenabled HAM2 ISI and set it to Level 3 isolation. This helped with 1Hz oscillation seen in REFL. Then we set HAM3 isolation to Level 3 from Level 2, and further decreased the 1Hz noise. This allowed for a long lock and I was able to align manually to get REFL down to 240 and MC TRANS around 2200.
We tried to engage WFS, but found it driving the lock to a bad place, REFL = 800. Kiwamu arrived, and is now working on WFS.
WFS are not well aligned, and MC2 TRANS QPD is high in pitch. This means the IMC alignment is good for REFL, but not for the IMC as a whole, which could be my alignment changes to MC1, or changes in the PSL input beam pointing from PZT's being turned off and on yesterday (see NOTE), or changes to the PSL input beam pointing from temperature change made by Rick in the PSL enclosure, or all 3 combined.
NOTE... I ran scripts attached to the WFS medm screen yesterday, which apparently have NEVER been run here before, and were written at LLO. Why do we do this to ourselves? I was telling Jeff the script to turn off ASC turns off the PZT offsets WHICH SHOULD NEVER BE TURNED OFF!!! Now I learn from Kiwamu that no one has ever run any of those scripts at LHO. Are these scripts even used at LLO? This sort of thing is a death trap for an IFO.
Currently Kiwamu is working of WFS.