Sorry, had a busy morning/afternoon.
Had a 6.0 EQ from Chile knock us out of lock (17:21). Seismic signals were elevated for about an hour, so waited that out. Then after that I did a few tweaks to see if we could reacquire with the alignment we had been running. Gave H1 about an hour while we waited. Then we called that off, and went for an Initial Alignment. H1 then locked up with mostly no issues shortly thereafter.
The minor issues we did have were related to making some Guardian changes ("we" being Sheila) to include PRMI into lock acquisition. I believe she also added an OMC PZT slider step as well.
Once at NOMINAL_LOW_NOISE, Sheila took some time to run some commissioning work while L1 was down.
21:35 Went back to Observation (@73Mpc)
Just to clarify, we noticed a problem with the PRMI state that has been in place (It did not turn off the offloading to PRM top mass if it failed to make the transition to DRMI). I made some changes to fix this, which created a different problem. Now I think it should be fixed, but we haven't fully tested it. I hope to test the fix fully durring maintence tomorow, but for tonight if anyone decides to use these and runs into a problem feel free to give me a call.
I didn't do the OMC thing yet, that will be done durring maintence tomorow.
Also:
We were locked for a little bit before LLO rocovered from the EQ, so I had a chance to make a quick injection on ITMX ISI ST2 in the X direction (WP#5528). I used 0.0283 cnts at 75 Hz starting at 21:18 UTC October 5. The result is that it seems like if the 77-80 Hz noise is from scattered light, the scattering path does not include anything hanging off the ITMX ISI. With the same excitation applied to the ETMX ISI we had a borad peak in DARM, with this excitation on the ITM ISI we get a narrow peak which is a factor of 10 lower.