corey.gray@LIGO.ORG - posted 06:48, Wednesday 26 July 2017 - last comment - 07:11, Wednesday 26 July 2017(37786)
H1 Update: ETMx/y Violin Modes Rung Up Again
After the lockloss, PRMI didn't look good at all, so ran an Initial Alignment.
Locking hasn't been fruitful so far, and the violin modes continue to be a culprit as was experience after Maintenance Day yesterday. Have had a few chances to work on them, and so far have been focusing on ETMx AND ETMy.
First attempts were at DC Readout, but at this point they are rung up pretty bad.
Now looking at violin modes at the SHUTTER_ALS state. Fundamentals have been up around e-13.
Have had locklosses while trying to damp. Not sure whether it's because I'm missing other violin resonances while damping others.
Oh, and have also had the ETMx UL (i.e. ETMX_BIO_L2_MON) come up in an OFF state after last few locklosses (to clear/reset, one enters a 1.0 for the UL RMS RESET field & then take it back to 0.0).
This seems like a new feature since I was last on shift.