elenna.capote@LIGO.ORG - posted 19:31, Wednesday 07 December 2022 - last comment - 20:55, Wednesday 07 December 2022(66244)
Guardian changes for CHARD Y
I made some guardian changes to turn on the new CHARD Y control filter. I am not sure how well this filter will work for lock acquisition, so I have it set up to engage at POWER_10W.
- At POWER_10W, the CHARD Y is set to zero, FM5 is turned off, FM2 is turned on, and the gain is ramped up to 125. Has been tested
- at POWER_25W, I changed the CSOFT Y gain to 5 (was 10). Tested
- At MAX_POWER, I removed the code that lowers the CHARD Y gain to 10. Tested
- At ADJUST_POWER, I removed the code that lowers the CHARD Y gain to 10. Tested
- At LOWNOISE_ASC, I changed the CHARD Y gain decrease so that the gain is lowered to 75, and FM6 turns on in addition to FM9. Not yet tested
Going to lownoise ASC does not work. The oscillation was a ring up at 0.45 Hz. My guess it that some combination of lower CSOFT Y gain and the reduced CHARD Y bandwidth do not play well. Reverting the CHARD Y bandwidth changes did not avert the lockloss.
This is very odd because I got to this state last night, but I ran through it by hand. I don't understand why it did not work tonight.
At the next lock, I commented out all lownose asc changes to CHARD Y in the guardian, and increased the csoft y gain back to 10. Then, after I ran the lownoise asc guardian state, I made the lower bandwidth changes to chard y: lower gain to 75, turn on FM6 and 9. Everything was fine. Then I tried to lower the csoft y gain to 5. Many ASC loops immediately began to ring up at 0.45 Hz. I quickly returned the CSOFT Y gain to 10.
I am uncommenting the lownoise asc changes for chard y, but keeping the csoft y gain at 10.