TITLE: 02/04 Owl Shift: 08:00-16:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Observing at 65Mpc
INCOMING OPERATOR: Corey
SHIFT SUMMARY: Not much. One lockloss (alog33885) . No issue relocking.
Nothing obvious except for the excessive ground motion in 3-10 Hz band. Chunk of snow fell off? I didn't hear anything in the control room.
Verbal alarm also crashed.
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TITLE: 02/04 Eve Shift: 00:00-08:00 UTC (16:00-00:00 PST), all times posted in UTC STATE of H1: Observing at 69Mpc INCOMING OPERATOR: Nutsinee SHIFT SUMMARY: The TCS_ITMY_CO2 guardian node transitioned back and both between LASER_UP and FIND_LOCK_POINT a few times knocking us out of observing. It seems stable now. One lock loss with no real issues reacquiring other than a small tweak to the end Y TMS alignment to improve the green arm power. I restarted verbal alarms after the lock loss as TJ had requested. LOG: 06:39 UTC restarted video2 06:55 UTC Changed phase to damp PI mode 28 07:00 UTC Changed phase and sign of gain to damp PI mode 27 08:01 UTC Changed sign of gain to damp PI mode 28
06:49 UTC
06:03 UTC Cause unknown
Restarted verbal alarms as requested by TJ.
The TCS_ITMY_CO2 guardian node seems to have settled. No other issues seen.
02:27 UTC The TCS_ITMY_CO2 guardian node has transitioned to FIND_LOCK_POINT. The number of SDF differences is varying. One instance of them is attached.
The guardian node has returned to LASER_UP. However there are a number of SDF differences remaining. I have accepted them (screenshot attached). Set back to observing at 02:40 UTC. Just got kicked back to commissioning again. Same issue...
Trying again. Accepted SDF differences attached.
Got kicked out of observing again while I was out of the room. Setting back to observing. SDF differences attached.
Here I attached some plots regarding the event to compare to what happened last time.
This looks like it started with the spike in the lsrpwr_hd_pd channel. That is the measurement channel for the laser output power that is used to stabilize the laser.
There is then a corresponding correction to the PZT position, and a change in current to the laser associated with this move. After that the slower temperature change happens to bring the PZT voltage back to the middle of its range. This all happens in the first 1/3 of the plots shown here. By the middle of the plot, the laser is unlocked and trying to relock.
Firstly, I suspect that spike in laser power that triggered this may not be real. We should take a closer look at it, but it may be related to the other spikes and jumps you're seeing on the Y-arm laser.
Secondly I think we should revisit the intentions for this laser locking system. It is meant to keep the power of the laser relatively stable, not to kick us out of observation mode.
TITLE: 02/03 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 65Mpc
INCOMING OPERATOR: Patrick
SHIFT SUMMARY:
Locked for over 31hrs. Winter weather rolled in during the afternoon & we should last us until morning.
LOG:
TITLE: 02/04 Eve Shift: 00:00-08:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 64Mpc
OUTGOING OPERATOR: Corey
CURRENT ENVIRONMENT:
Wind: 10mph Gusts, 9mph 5min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.31 μm/s
QUICK SUMMARY:
Locked for over 31 hours.
After the PI Mode activity on Wed night, and after Keita asked me to measure the modes, I went through an exercise of looking at some of the PI Modes (mainly for my own "homework" since I've luckily not had to deal with needing to change filters to damp these out (changing phase has worked for me...and sometimes gains on rarer occassions---perhaps I've been lucky).
While going over the PI Damping wiki (& also having Jim & Nutsinee show me) & went about exploring the frequencies of PI Modes which either (1) have PLL on and/or (2) have a phase value. For these PI Modes, I looked at:
Here's what I recorded:
| Mode | Basic | BP Filter peak in Bode Plot | BP Notch Value | Meas Today |
| MODE1 | 14985 | 186.6(14986.6) | 185 | 14985.6 |
| MODE2 | 15520 | 717.8(15517.8) | 720 | 15521.6 |
| MODE3 | 15606 | 807.2 (15607.2) | 806.5 | 15607.4 |
| MODE9 | 14980 | 177.8 (14977.8) | 180 | 14980.6 |
| MODE10 | 15518 | 717.8 (15517.8) | 718 | 15516.9 |
| MODE17 | 15542 | 743.0 (15543.0) | 742.2 | 15542.9 or 15543.5 |
| MODE18 | 15008 | 207.0 (15007.0) | 207.9 | 15008.5 |
| MODE25 | 15541 | 741.2 (15541.2) | 741.2 | 15542.9 |
| MODE26 | 15010 | 209.9 (15009) | 209.5 | 15010 |
| MODE27 | 18043 | 237.7 (18037) | 237.5 | 18037.5 & 18040.2 |
| MODE28 | 18059 | 254.7 (18055) | 255 |
18055.2 |
Starting CP3 fill. LLCV enabled. LLCV set to manual control. LLCV set to 50% open. Fill completed in 326 seconds. LLCV set back to 12.0% open. Starting CP4 fill. LLCV enabled. LLCV set to manual control. LLCV set to 70% open. Fill completed in 457 seconds. LLCV set back to 37.0% open.
Increased CP3's LLCV to 15% open from 12% and CP4's LLCV to 39% from 37%. Will likely make another adjustment this afternoon.
~2140 hrs UTC -> Reduced CP3's LLCV to 14% from 15% and CP4's to 38% from 39%.
Krishna
I took a quick look at the data from the PEM STS at EndY, which is mounted on the BRSY platform. The channels are mentioned in 33533.
First plot shows the GND STS (used by SEI) and the PEM STS converted to angle units (by multiplying by w^2/g) in comparison to the BRSY - rX. The wind-speed during this time was less than 2-3 m/s. The GND STS sees less signal than the BRS below ~50 mHz, but the PEM STS sees a lot more. The second plot shows the coherence between some channels and the third plot shows the X-direction signal. The Z channel is not recorded so I can't access it through ligodv-web.
The source of extra noise in the PEM STS could be - a) Insufficient mass centering or b) Extra temperature noise either on the STS case or the table it sits on; more insulation to the table and the STS case might help...
When allowed (Tuesday?) we could go check the centering and center it up as needed--Hugh
On Tuesday went to EndY to Check on and Center the PEM STS Masses
Upon arrival checked the mass measurements right away: U V & W were -3.7 -1.8 & -12V. The X axis is generated from U V & W but the Y signal comes just from V & W. See manual for axis mapping.
While the W mass is clearly out to lunch, U is also high >2volts. However, as W contributes to both X & Y signals (but with different weightings) you'd think both X & Y signals would be noisy. One might even argue that Y(North on STS Manual) would be even worse than X.
This morning, Thursday ~0930pst, with an IFO Lockloss, we went to the VEA again to check and found the U V & W masses exactly where I recorded them almost two days ago after nearly two hours of centering attempts: 9.9 12.9 & -13.5V. After recording the voltages this morning, we hit the centering button and left the VEA.
Now see the attached 60 hours of minute trends. Before the Tuesday mass centering activity, the X & Y time series values suggest fairly zero'd signals; I did zoomed in and they are. During the interum ~2 days before this morning's look, the Y signal was pined to a rail. Noting my U V & W voltages, before Tuesday just W was on it's rail but after Tuesday, essentially all 3 masses were at or near a rail. This further suggests you can not just look at the X Y & Z signals to assess the mass centering.
So, clearly, waiting for the masses to come off their rail did not yield results. In addition, it appears there is a higher frequency noise on the channels showing up on X after Tuesday and now on Y after this morning's centering.. We will go measure the mass voltages when allowed. I did leave some leads hanging off the monitor port for voltage measuring but they are mostly insulated and I don't think they are causing noise. However, we'll remove these next time just in case.
Meanwhile, the positive glitches seen on the time series (average is still under the min trace but the max [black] is way higher than the average) are not continuous. I guess these show up as the 1/f noise starting around 40Hz on the spectra, second attachment. The reference traces are 1200utc 31 Jan (before the Tuesday activities.) Note the higher noise on the X (pink) trace compared to the Y signal (cyan.) I checked the wind, it did not seem to be an issue at that time.
I have to just throw this in and run.
Here is a comparison of the SEI Ground STS and the the PEM unit on the BRS. These have some gain difference I don't understand yet but I made them the same by multiplying by the ratio at the useism. At this BW, the PEM is not happy.
9:54 Back to Observe