No obvious seismic jolt for lockloss, BUT we had been riding some high useism.
Locking Notes:
1) IMC not locking! (it did look misaligned on Trans when it tried grabbing lock)
- Going through Jenne's troubleshooting doc, the first thing I did was clear WFS history for IMC: NOTHING
- Check MC1/2/3 witness sensors. There was a step in most of these channels, so I steered all of the MC's to values when the IMC was locked & this did the trick. (see attached plot for the step which occurred after the lockloss).
2) H1 Locking Status: Have had a couple of failed attempts after & before CARM Reduction steps.
- To allow locking of PRMI, I had to adjust the BS & PRM quite a bit.
- I have been able to lock DRMI & made it past CARM reduction steps once (dropped at ANALOG CARM when all signals became noisy & ASAIR spot looked ugly), and also lost lock before twice CARM reduction at SWITCH TO QPD steps.
- Next going to check Bounce/Roll modes & then try CARM reduction steps by hand.
- (texting Jim about useism and he recommends staying in the WINDY states.
Have had a few more DRMI locklosses drop before the CARM steps & earlier.
Going to try an Initial_Alignment and see if this changes any results here. If not, will return to investigation of steps before CARM REDUCTION.
Mode Cleaner continues to be a pain.
This is my third instance of needing to Clear Histories. (mainly the Pitch outputs were high).
Going back to Initial Alignment.
When you get it re-locked, try letting it be for about 15-20 minutes to give the loops time to optimize the alignment, maybe. That's what I do.
18:23 - 21:23 Out for Locking & Alignment (during high useism)
Assuming the lockloss could be related to our high useism (no jolts seen on any of our BLRMS seis bands).
Tried to do what I could to get it back up w/o a full Initial Alignment (by tweaking MCs to get IMC back & then usual BS/PRM), but after several locklosses after DRMI, I opted to give an Alignment.
After the alignment, dropped a handful of times, but went step by step in Guardian and finally got through the CARM reduction steps (I never got to a point where I needed to run Guardian line by line...talking with Jim we just wanted to get it through the CARM steps in this high useism). At any rate, finally made it past the CARM reduction steps and up to NOMINAL_LOW_NOISE!
Did notice a few SDF Diffs that I ACCEPTED:
- PSL ISS REFSIGNAL (had a tiny diff...not sure why since I didn't touch this channel)
- IMC WFS GAIN: I did touch this gain when clearing WFS histories. I apparently took it to a paltry 0.004 instead of returning it to the normal 0.04. So, I slowly walked the gain back in 0.001 steps & then had a teeny tiny SDF diff--which I ACCEPTED.
Ed: What step were you suggesting I should have paused?
The IMC was a bit frustrating through all of this. Have not had to be so hands-on to it in my experience over last few months.
Currently running at 66Mpc. and can certainly useism oscilltion on LSC signals on Strip Tools, the Tidal StripTool, and even PI Mode28.