We are currently Locked and have been for over 3 hours. We've been dropping out of Observing a few timnes due to the FC unlocking, and a couple times it was able to relock itself, one time I had to adjust FC2, and currently I've been working on relocking it but I've been having trouble. I've adjusted FC2 to maximize flashes, I've trended back FC1 and FC2 to a time yesterday when the green trans was good based on the DAMP INMONs and now the M3 Witness channels, and none of that has worked. FC2 seems twice as noisy as usual in pitch and I'm wondering if that's affecting things? The wind is getting in the high 30s at M/EY?
Daniel, Oli
After trying to work on the alignment for the filter cavity (I tried following 72084 and wiki) and not being able to get the filter cavity to stay locked for more than a couple of minutes, I contated Daniel. He tracked down the FC beam spot control that Camilla and Sheila had turned on earlier today (85149), and we tried turning the inputs off to the H1:SQZ-FC_ASC_INJ_ANG_(P,Y) filter bank. The first SQZ lock after this lasted less than a minute, but the next one kept the filter cavity locked for a few minutes. We were unsure as to if this was the solution, but since it didn't lose lock right away, we might as well go back into Observing, so I accepted the SDFs of those inputs being off and we went back into Observing.
As I was writing this, the SQZer lost lock again, so this was not the solution. I let it relock on its own and that worked, and I let it keep the ASC_INJ filter inputs on and accepted those back into SDF since that isn't the issue.
Oli and I checked that neither the FC beamspot control or FC ASC were running away or had signals any different than normal locked times. The ASC YAW signals had some slightly noisier times with FC_ASC_INJ_ANG_Y up to 0.003 rather than the max 0.002 earlier in the day. Oli noted that the wind had picked up during the locklossy time, maybe that is to blame.
- FC beamspot control: locked time earlier today, locklossy period
- FC ASC: locked time earlier today, locklossy period, some yaw signals noiser.
We thus don;t think there's reason to keep the FC beamspot control off but are leaving FC beamspot control off for tonight just incase as it's nearly the end of Oli's shift. It could be turned back on tomorrow AM.
Regarding what Camilla said about the ASC being twice as loud during this time - it looks like that started earlier this morning (ndscope1) - before it would make sense if we were counting on my wind theory below being the cause, so my theory is probably incorrect. It looks like then something was changed prior to 06/18 16:50 UTC that is causing the differnce in the FC ASC, which may or may not be related to the FC unlocking issue.
Here is my wind theory - that is currently backed up by only a few data points - is that when the wind is blowing against the FCES at a specific angle above a certain speed, it wiggles FC2 more than it should. I kept seeing messages from SQZ_FC saying that FC2 is too noisy, and FC2 M1 DAMP IN P was twice as noisy as it was a day ago when I trended the pointing back. However, Camilla did note that the Yaw ASC signals were a bit large, so obviously that's the opposite dof from what I saw. Anyway, here's a quick trend back of a few days showing a correlation between the wind pointing in the direction almost perpendicular to the FCES, and the SQZ FC subsequently unlocking multple times while the wind is high (ndscope2)
