Louis and I started morning locking once Oli re-re-ran initial alignments with the "correct" green camera offsets (ones set by the baffle scripts).
We got to DRMI ASC, and the SRC P error signals looked close to zero, so I tried engaging SRC1 and SRC2 P. However, we saw slow large oscillations that went away when the SRC P loops were turned off. I also saw that the alignment wasn't brought to the best buildups- I had to move SRM pitch more to maximize. I also reset the POP A offsets (SDF attached), which is a minor change but we have the best buildup now (ignoring the >200 buildup from last Friday)- POP18 is 167 and POP90 is 20. As an aside, I think we need to pico onto the POP QPD sled. The POP A offset required is very large, about 0.98 in both pitch and yaw. We're probably close to or falling off of POP A and the same is true for POP B. Perhaps we can lock DRMI, close PRC1 with the current offsets, let it converge, open the loop, turn off the offsets, and pico to bring the beam closer to the center of the QPDs.
I have now created separate "use DRMI ASC" flags for SRC1 and SRC2 pitch and yaw. The yaw flags are set to TRUE, and the pitch are set to FALSE. The ISC_DRMI guardian will now separately engage these loops in ENGAGE_DRMI_ASC. This means that only SRM and maybe SR2 pitch will need to be hand-adjusted for buildups in DRMI ASC. Tagging opsinfo.
Louis and I tried to go through TR CARM four times:
- Try #1: tried running straight through carm to TR, lockloss
- Try #2: went to start TR carm, saw that the REFL_DC_BIAS output signal had an offset. Tried adjusting the TR CARM offset to remove the offset. Had to lower it to -0.3. REFL DC BIAS was around zero. Tried measuring TR CARM using the template, had no coherence, bumped up the template excitation by factor of 100. Measurement showed low TR carm loop gain, by roughly a factor of 3. Tried raising the REFL DC BIAS gain from 6 to 12, lockloss. See attached "TR carm fail 2" for measurement.
- Try #3: Decided maybe we railed the input to the common mode board on last try, decided to raise the analog gain instead. Went up 3 dB, remeasured. TR carm gain looked better, but still low. Went up 1 more dB step. Immediate lockloss. See attached "tr carm fail 3" for measurement.
- Try #4: Oli alerted us to an incoming earthquake from Panama, big enough for big red button. Oli spoke to Jim, was advised to press big red button asap. No chance to try carm on tr.
We're holding in down while this large earthquake passes.
I want to re-emphasize that we are still having trouble relocking the IMC after lockloss. The IMC will acquire lock, and the boost will kill it. This can get intense enough that the boost kicks the FSS which then kicks JAC. The only way around it is to either wait a really long time, or to hold the IMC guardian in acquire, wait a minute, and then engage boost. Doesn't always work, but can be faster than just waiting forever. Tagging IOO, someone needs to look into this boost.
In the late afternoon, we returned to locking, and the guardian errored at DRMI locked check ASC, because the loop convergence checker uses the loops named in the use DRMI list, and due to my edit above it tried to check the convergence of "SRC1_P_Y". I don't know a good way around having a true/false bit for the p/y dofs of a particular dof, so my short term solution is to just have SRC1 and SRC2 set to TRUE, and I commented out the engagement of SRC1 P and SRC2 P in the engage DRMI ASC state, so only the yaw loops will come on.