Terra, Travis, Kiwamu,

Here are some unexpected issues that we addressed tonight.

• AS36 -> SRM
  • As mentioned earlier (30295), we had stability issue with the AS36 -> SRM loop in the DRMI state with the arms held off resonance.
  • One immediate human error we found was an integrator not engaged in DC3 pitch loop.
  • However, engaging the integrator in DC3P did not improve the behavir of the loop running away.
  • In the end, we changed the input matrix. AS36BI: +2 --> +1.
  • This solved the issue. Not sure why we had to change the input matrix.
• AS WFS DC and fast shutter
  • At one point, we ran into a situation where ISC_LOCK did not proceed because the shutter guardian reported a failure in a shutter test.
  • This was found to be a failure report from the dark test in which the light level on AS WFSs A and B were checked with the shutter closed.
  • In the end, we found that the AS WFS DC signals now had a slower low pass filter (a 2nd order butterworth at 1 Hz in FM1), which was too slow to give a low enough light level. This used to be a 2nd order butterworth at 5 Hz yesterday.
  • We re-installed the 5 Hz BLP in FM2 and edited the FAST_SHUTTER and ISC_LOCK guardians so that it uses FM2 when in test.
  • It worked once.
• AS90 jumped multiple times
  • We witnessed a funny behavior of AS90 a few times tonight.
  • It suddenly changes its level by a few % or so when DRMI was in lock with the arms helf off resonance.
  • Times to look at are around 2:13:19 UTC and 3:30:00 UTC.
  • DRMI did not lose lock.