Naoki, Corey, Vicky
Corey is taking it to OBSERVE without squeezing tonight.
We traced down an issue to FC2 0.3-0.5 Hz oscillations, which maybe is worse right now due to wind. We think this excess FC2 motion is preventing FC from locking.
FC2 0.3-0.5 Hz oscillations screenshot - see the FC Green VCO control signal trying to lock and failing - at the same time, we can see the FC2_M1_L oscillations around 0.4 Hz, even with no control signals sent to FC2 SUS. So, seems like FCGS VCO is trying to track the FC2 L oscillations, but the real FC2 motion is too much for the FCGS VCO to hold lock, and this prevents further locking. Corey says perhaps this FC2 motion is extra bad right now due to the wind. I don't remember this issue in O4a. Without FC2 L motion calming down a bit, I don't think we can hold a stable FC lock.
So, we decided to go to Observe without SQZ tonight, at least until the wind calms down. Maybe could try SQZ later if wind calms down.
Edit: It seems FC has been struggling to lock with winds > 30-40 MPH these last couple days, see screenshot with FC locking and wind speeds.
Rahul, Corey, Naoki
Rahul found that FC2 M1 OSEM OFFSET were OFF, which should be ON. He will report the detail later. After we turned on the offset, FDS was recovered. So we went to observing with squeezing.
As I was getting ready to change H1 configuration for NLN w/ NO Squeezing, Rahul mentioned the input filters for the FC2. So, before I changed anything, we halted No-Squeezing and decided to try for Squeezing---Naoki was able to get us there fairly quick. And then we went to Observing.....but this only lasted about 30min before the FC unlocked again. (this also happened to coincide with winds increasing again with gusts touching 40mph)
So we may still have an issue with FC2/HAM8 isi shaking (I believe Naoki & Jim were saying the noise is around 0.3Hz.)
I will return to following the procedure for No-Squeezing as Vicky posted originally.
And just like that, H1 had a lockloss.....about 5-sec prior to the lockloss I heard a loud creak in the Control Room/building which I'm assuming is due to a big wind gust. :( (see attached for a look at the winds---it's windier than last night! And last night at around this time is when the winds increased and the SQZ started having issues during a 4hr wind storm)
I still have NOT made the changes to SQZ guardians for NO SQUEEZING.
I have switched ON the osem input filters after they were found to be OFF on SUSFC2 (HAM8) and have also accepted them in the SDF.
