patrick.thomas@LIGO.ORG - posted 20:02, Wednesday 14 December 2016 - last comment - 23:45, Wednesday 14 December 2016(32583)
Ops Evening Mid Shift Summary
Lost lock twice after PI mode 26 rang up. Nothing I tried seemed to affect it. Called Terra while the mode was ringing up the second time. She is now logged in remotely to see if she can help diagnosis it.
TCSY chiller flow is glitching.
Comments related to this report
terra.hardwick@LIGO.ORG - 23:45, Wednesday 14 December 2016 (32587)
When I called during the second lock, Patrick had walked through all the usual things to try and check but we couldn't get a response; I assume the mode was too rung up by then to turn easily and we were having to be careful with gain to not saturate. After the second lock loss, I logged in and was able to damp remotely at the very first sign of ring up. I moved Mode26 bandpass filter up by 0.5 Hz, but the original bandpass had still been encompassing the peak and the PLL had been engaging. Not sure why damping hadn't been seeming to have an effect. I was able to damp by flipping the sign of the gain and then decreasing the phase in ~10 degree steps every 10 min or so as the mode creeped back up.
When I called during the second lock, Patrick had walked through all the usual things to try and check but we couldn't get a response; I assume the mode was too rung up by then to turn easily and we were having to be careful with gain to not saturate. After the second lock loss, I logged in and was able to damp remotely at the very first sign of ring up. I moved Mode26 bandpass filter up by 0.5 Hz, but the original bandpass had still been encompassing the peak and the PLL had been engaging. Not sure why damping hadn't been seeming to have an effect. I was able to damp by flipping the sign of the gain and then decreasing the phase in ~10 degree steps every 10 min or so as the mode creeped back up.