Tidal and ASC (PRCL1, DHARD) was running away.
The ifo is locked at NLN but not observing. RF45 still glitching.
Lockloss again at 07:00 UTC
DHARD ran away again. I lowered the gain as soon as I noticed the oscillation. The amplitude of the oscillation didn't seem to decrease. Maybe I didn't catch it quick enough?
I also couldn't connect to the nds sever. So no dataviewer.
I will be taking a few minutes to grief.....
Dataviewer seems to work on a different computer. Resume relocking.
Hmmm, maybe we just should always be using the lower DHARD gains when we're on the 45mHz ISI blends? I think DHARD Pit is usually 10, and should go to 7. DHARD YAW is usually 15, and should go to 10.
I don't think that the oscillation that nutsinnee shows in the screen shot is the one that can be fixed by lowering the gains, that is around 0.6Hz, while the screenshots show an something happening at around 20mHz. This large low frequency motion of DHARD yaw was happening durring earthquakes durring ER8.
I would be more inclinnded to leave DHARD gains alone or try to increase the low frequency gain for Yaw, depending on what was really happening (was this ground motion or a loop oscillation?). I think that lowering the gain could actually make things worse in either case.
For a rough model of DHARD yaw loop with thee new boost added, see https://alog.ligo-wa.caltech.edu/aLOG/uploads/21768_20150921225603_DHARDYAWOLGwithboost.png
