thomas.shaffer@LIGO.ORG - posted 04:30, Tuesday 11 July 2017 - last comment - 04:48, Tuesday 11 July 2017(37441)
Ops Mid Shift Report
After the 6.6M New Zealand quake I ran an initial alignment with no issues, but then it would lose lock very randomly. I couldn't make it past DRMI for a long time, with the FSS oscillating often on lock losses.
I have finally made it to DC_READOUT_TRANSITION but the 507.194hz ETMX mode has been ringing up with the current settings from Guardian. Changing the phase from +60 to -60 started to help, but now it seems that to have flattened out. There are no +/-30deg filters in that bank so I'm pretty limited, but a smaller positive gain (~5) with -60 gain seems to be my best option.
That mode was definitely being rang up by something. I had to change phases and gains once a minute or so or it would begin to ring up. With the bank turned off it would ring up pretty fast and at 6.9RMS already it was dangerous. Since I was running out of ideas I went to increase the power but it died immediately upon entering DC_READOUT. Expected when the mode is that high.