Got called at 10:57PM (PT) and IFO was actually locked in NLN with one SDF Diff, which I accepted and is screenshot is below (IMC_DOF_1_P TRAMP from 0 to 3 and IMC_DOF_2_Y TRAMP from 0 to 3).
Good timing for this since the 1Hz ringup was happening. I saw earlier today that turning on the ASC High Gain might help with this so I turned it on and it seems to be working.
SQZ also looked terrible inthe high-frequency domain. I ran the OPO temp scan and the SQZ Angle, but this did not seem to improve anything (plot attached).
Additionally, the EY Roll Ringup that plagued Ryan C's EVE shift is indeed happening again. I'm unsure what to do about this since it seems he and Rahul tried a multitude of damping techniques without avail.
ASC High Gain was turned off ~5 minutes after it seemed to be working. A minute later, we it rang up again and we lost lock.
So there's two issues (or maybe they're related I don't know):
1. 1Hz Ringup that can be survived while locked but only in High Gain settings
2. ETMY Roll mode which just rings up consistently
Out of ideas - will continue to investigate but nothing seems to be helping.
Called Rahul for help with the EY Roll Mode
The plan:
- Move to NLN very very slowly stopping at every stage of powerup and watching for violins
- Once at NLN watch for the 1Hz ringup and activate High Gain settings
The issue with this plan is that it seems that without the high gain on, the oscillation prompts a lockloss but we'll see what happens as I watch it closely this time.
Lost lock at OMC_WHITENING after spending ~10-15 minutes at each powerup state to ensure EY Roll mode and Violins were low. They were. The 1Hz ringup started on queue as soon as LOWNOISE_ASC turned on and got worse. I think I turned on the ASC High Gain too early - confused as to what caused this lockloss. Trying again. It seems that the slow method works to avoid the EY Roll Mode ringup.
Additionally, Elenna's alog 87658 talks of her plan for how to try to avoid the 1Hz ringup and it involves DHARD_P to HBW using turning off FM8, then FM4. I will do this instead of the entire HBW ASC EQ script.
Lockloss tool sees EY glitching 1.2 before lockloss.
After some DRMI troubles, finally back to where I was before. In about 10 minutes, EY Roll Mode permitting, I will attempt to go to NLN and watch the 1Hz ringup, turning on HBW DHARD_P when I see the ringup.
It worked! (for now). We're in NLN with bad SQZ though similar range to last time we were locked (which isn't that good). The EY Roll Mode is on the rise though and if this lock is like the ones Ryan C (EVE) had, then usually they rise until lockloss in ~45 mins to an hour. I'm going to give IFO at least 10 minutes before re-engaging the DHARD_P LBW. The ringup comes back thereafter according to my last lock and Ryan's too. So, let's see what happens.
Really doesn't look great especially that as soon as we're near NLN, the EY Roll mode begins to trend upwards. Violin modes are going down though.
Well... The mode has rung up again after switching FM4 and FM8 back on... I don't know what to do here. Meanwhile EY Roll Mode is still ringing up despite locking veeery slowly per Rahul's advice.
EY Mode 15 is rung up slightly and damping it per the settings has made things worse - resetting its gain to 0 seems to calm it down.
My not-very-creative-out-of-options plan now is to wait here in these settings and attempt to go back to LBW DHARD P in another 20/30 or so... However, by then we will probably have lost lock due to Roll EY ::(
As expected when I went back to LBW, DHARD P rung up again so that doesn't work either.
While violins are high, they've been much higher before so we're not really ringing them up - they're all reporting as damping now anyway.
OMC DCPDs are going quite wild I assume due to this Roll Mode (attached).
If we lose lock here, I'm just going to IDLE IFO due to inability to stay locked and to avoid any more violin mode ringup. On the bright side, it's nearing DAY shift, involving well-rested experts.
Lockloss 11:51 UTC - IFO in IDLE.
