The TCSY chiller flow seems to be struggling for the last 40min or so. This doesn't seem to be the normal issue of an air bubble because it is not recovering as it normally would. I saw a WP for the replacement of this flow meter but I didn't see an alog stating that it happened.

Attached is an hour trend of the flow rate.

TITLE: 12/06 Owl Shift: 08:00-16:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Observing at 65.1367Mpc
OUTGOING OPERATOR: Travis
CURRENT ENVIRONMENT:
    Wind: 9mph Gusts, 7mph 5min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.36 μm/s
QUICK SUMMARY: Travis handed me a locked IFO, let's  hope we  can keep it that way.

For those headed to the site: There is a large amount of slush on the ground and the tempurature is just now getting below freezing, so I imagine that it will turn to thick ice by the time that people show up. Be careful!

TITLE: 12/06 Eve Shift: 00:00-08:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 72.9403Mpc
INCOMING OPERATOR: TJ
SHIFT SUMMARY:  Other than the lockloss due to PSL trip, not a bad evening for locking. 
LOG:

See previous aLogs for the play-by-play tonight.

For DaveB, there was a /ligo server connection interrupt at 1:32 UTC.

For DetChar, Keita wanted to acknowledge/remind that Observing lock stretches for today have an ion pump running at BSC8.

PSL dust monitor is still alarming periodically.

7:57 GRB alert.

Straightforward relocking after PSL was reset.  No IA required, just a typical bit of tweaking of ALS and PRMI. 

Lockloss due to PSL tripping off.  Currently on the phone with Jason working to remotely restart if possible.  Will update as I know more.

We have been locked in Observing for almost 2 hours.  No issues to report.

I used the lockloss2 script that automatically checks for sus saturations and plots them using the lockloss tool, and saw that one of the three locklosses (2016-12-05 16:02:42 UTC) in the last day or so was probably caused by a glitch on SR3.  The attached screenshot shows the timeline, there is clearly a glitch on the top mass of SR3 about 0.2 seconds before the lockloss.  

The dither outputs (which we use for the cage servo) don't show anything unual until after the lockloss, which means that this is not a cage servo problem.  Looking at top mass OSEMINF LF and RT are the two that seem to have a glitch first, at about the same time. 

I've added a lockloss template /ligo/home/ops/Templates/Locklosses/channels_to_look_at_SR3.txt  for any operators who have an unexplained lockloss and want to check if it is simlar to this one. 

Back to Observing at 2:27 UTC.  No issues with relocking.  A slight tweak of PRMI was all that was needed.

Lockloss at 1:58 UTC.  No obvious cause.  Was coincident with me rebooting the OPS workstation.  OPS workstation 2nd monitor shut off, first monitor was showing symptom of needing to be rebooted (slow, jumpy mouse movements, etc.),  verified that the cable was still plugged in, and hardbooted.  Seems to have come back fine with both monitors, but seemed I have never seen this issue before so might need some further investigation.

We are now back in Observing mode.  No issues were encountered during the lock sequence, went all the way to NLN the first try after Sheila finished here camera work.  I ran Keita's a2l check script which showed that running a2l would be prudent.  I then ran a2l.  Set to Observing at 1:50 UTC.

I repeated the measurement from alog 31399.

The attached plot looks very similar for all traces but PSL-ISS_PDB_REL—indicating that the changes described in alog 32206 significantly reduced the extra noise in the first loop ISS path.

We also see that the new REFL_A_RIN channel (see alog 32191) is working fine.

Between 10 and 30 Hz there is coherence between REFL_A_RIN and the DCPDs. There is a clear shelf in both spectra pointing towards a parasitic interferometer path.

PT170 and PT180 were installed in March 2016 when the X/Y beam manifold volumes were vented. PT140 was installed in Sept. 2016. Attached is trend from time of installation. Looks like PT170 & PT180 have been drifting up since after closing and re-opening isolation GVs 5/7 for HAM6 vent. We burped in accumulated gas from gate annuli but I'm not sure what the second hump is from April 9th. No log entry found.

6373 increase rate of h1ascimc model

Daniel, Jim, Dave:

The h1ascimc model processing rate was increased from 2048 to 16384.

6374 add 16kHz LSC channel to DAQ

Daniel:

6378 Add channels to DAQ broadcaster

TJ(Detchar), Dave:

Slow channels were added to the DAQ DMT broadcaster

6371 Relocate digital camera17

Richard, Jim:

Digital camera #17 was relocated to PRM

DAQ restart

Dave:

DAQ was restarted once at 11:49PST to support model work.

3:08 pm local

Took 39 min. to fil CP3 at 50% open on LLCV. Raised nominal level from 17% to 19%.

Summary:

OPLEV EX laser glithes were reported to be causing DARM glitches by detchar (e.g. alog 31810) even though EY is no worse or maybe somewhat glitchier (1st attachment, this is a week's worth of trend before Jason made an adjustment). It seems like this is due to a hidden design feature that there's a fixed 0.1uf cap across transimpedance resistor, which gives different pole for different resistor.

As a quick fix I'll insert digital zp(160,16) for all EX segments, as it seems to me that we cannot change the transimpedance without accessing the receiver module on oplev pyron.

Details:

T1600085 tells us that the effective transimpedance and the whitening gain of ETMX and ETMY are [2*10k,18dB] and [2*100k,0dB] (a factor of 2 comes from the differential drive, physical transimpedance is either 10k or 100k). They both use two stages of whitening filters too.

D1100290 shows that there's a 0.1u cap across the transimpedance resistor. The pole formed by 0.1uF cap and [10k, 100k] resistor is [160Hz, 16Hz].

Analog signal of each segment including whitening gain is

ETMX ~ 8*2*10k*zp([],160Hz)*photocurrent (a factor of 8 due to 18db whitening gain)

ETMY ~ 2*100k*zp([],16Hz)*photocurrent.

DC level is about the same but ETMX has an effective zp(16,160) whitening relative to Y. Look at RIN (second attachment) and PIT and YAW signals (third).

Residual power glitch that isn't canceled out by power scaling goes into the oplev PIT, and the effect is  worse for ETMX due to this difference because X and Y has the same damping filter with similar gain. For f>300Hz the PIT signal is limited by the electronics noise, so the power glitch at this frequency directly goes to oplev damping without any cancellation.

Inserting zp(160,16) for all EX segments will, for the moment, make EY and EX about the same.