TITLE: 09/25 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Calibration
INCOMING OPERATOR: Corey
SHIFT SUMMARY:

IFO is in MAINTENANCE and RELOCKING at FIND_IR

Shift was dominated by locking and calibration issues. Fought ALS to get to NLN then lost lock during impromptu CAL maintenance (though seems to be unrelated to the maintenance) right before shift end.

ALS Issues:

ALSY is still having locking issues. Thankfully, Keita was on-site when this happened and was able to help me out of it by shifting an offset (COMM Offset (V)) in ALS_CUST_CM_REFL - screenshot attached. This visible allowed ALSY to catch but the offset was moved to its maximum slider positon (-10V). The issue wasn't the counts, as we had had earlier today, but that ALSY was not locking at the maximum of its count (0.83 cts but locking closer to 0.6 and sometimes at 0.2, which is likely a different higher order mode).

Weirder yet was that after fixing this, neither PRMI nor DRMI were able to lock, which prompted me to start an initial alignment. The initial alignment reset the offset back from -10V to the nominal -0.025V BUT ALS was indeed able to lock, and quite quickly. In fact, initial alignment was fully automated, and so was normal locking, all the way upto NLN!

I'll keep the offset at its normal -0.025V instead of Keita's 10V fix since we didn't end up needing it.

Other than that, Keita went into comissioning for a very short <2 min to make/revert an ALSY change which I believe is related to alog 808280. I've attached the accepted SDF Diff.

Calibration Issues:

Louis and (and later, Joe B) got in contact with LHO Control Room while I was powering up and asked to reset the calibration due to very off/non-nominal calibration. Keita approved 1hr of CALIBRATION_MAINTENANCE. This was done, but in the process, we had to reload the GDS and reset the DTT, none of which caused any issues. We attempted to run a broadband measurements (attached cal monitor) but weirdly enough, the CAL Lines did not dissapear when I entered NLN_CAL_MEAS. By this time, I had already run the BB but by instruction from calibration, was told to cancel it. Well, cancelling it via ctrl_c and terminal closing didn't work and then we tried to wait until the measurement was done. This did not work either and it went over the 5 min time by another 5 minutes. At this point, we went the awg line clear route and forced the lines to close. So now, we are back to the earlier calibration state, which has a bad 15% error. Louis and Joe B are attempting to revert it back to a better state, which has <10% error. They're having difficulties with GDS so had to reload coefficients again, resulting in downed DTT again (for 12 mins). This happened successfully! Riding on this great luck, we lost lock 5 mins later...

Other:

• Unknown cause lockloss alog 808281
• Unknown cause lockloss (calibration says unlikely them). alog 808284

LOG:

None