Tega, Ross, Jim, Dave:

We installed new code for the models h1susitmpi, h1susetmxpi and h1susetmypi. The new code required a DAQ restart, which TEAM-PI obtained permission from TEAM-COMMISSIONING for this afternoon.

The purpose for the change was to make the code more efficient and claw back some CPU time on the h1susitmpi model which was running long (15-16uS for a 64k model). This was successful, it is now running in the 9-10uS range. ETMX is unchanged at 7uS, there is hint that ETMY is running one micro-second longer from 3uS to 4uS.

Now restored. Restarting the h1hwsmsr computer did the trick.

Here's more detail on what happened:

I came in this morning noticed a connection error on DIAG_MAIN. Opened up the HWS ITMs code and saw that every channel went white. There was no restart in the morning that could have affected TCS. I powercycled the msr computer and was able to rerun the code.

Dave also mentioned that various computer crashes between 2-4 AM local was normal during ER6. He didn't see this problem during O1. We also looked at the memory and CPU usage. Nothing is overloaded

we had some system problems over the weekend, here is a summary of the time-line. (These would appear to be unrelated events)

• Sat 14th 18:15 FMCS H2O-RO alarm
• Sat 14th 22:49 PSL turned off
• Sun 15th 03:05 h1hwsmsr IOC failed
• Sun 15th 04:52 h1ecatx1 IOC reported buffer error

The last issue caused Guardian problems with the ALS_XARM node. We did the following to try to fix it:

• stop-start the node
• reboot h1guardian0
• restart the h1slow-h1fe epics gateway
• power cycle h1guardian0 with epics gateway off

The power up of h1guardian sans epics-gateway gave even more CA connection errors, with HWS IOC and h1seib3 FEC. These were very confusing, and seemed to go away when the h1slow-h1fe epics gateway was restarted which added to the confusion. We need to reproduce this error.

After Patrick restarted the h1ecatx1 IOC the guardian errors went away.

See attached screenshot.

Forced PT100 Cold Cathode on in Beckhoff on h0vacly per Chandra's request (see attached). It is now reading ~1.01e-07.

Attached are HEPI Pump Trends for the past 45 days.  To my untrained eye, I don't see any egregious excursions in pump pressures.  SEI folks should review.

This completes FAMIS Request 4520.

Labeled HAM11 annulus IP (physically on HAM12) fell out of scale at around noon yesterday. 

Labeled HAM12 annulus IP (physically on HAM11) needs to be replaced. i.e. HAM11 annulus IP is working hard

https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=26804

9am local

1/2 turn on LLCV bypass --> took 22 seconds to overfill.

Lowered LLCV back to 20% (from 21%). Hot weather last week likely cause of long overfill times last Wed. and Fri.

*watch exhaust pressure after tomorrow's Dewar fill

SEI - No major maintenance plans scheduled. Ongoing tweaking with BRS.

SUS - model changes for HSTS scheduled for tomorrow.

VAC - GV measurements and manual CP3 overfill scheduled for tomorrow

CDS - Cables to be pulled for ITM ESD tomorrow. Auto restart of workstations to take place tomorrow morning.

PSL - the team sees no pressing reason to go into the enclosure at this time other than to do some DBB aligning tomorow, possibly.

The laser was off this morning.  The chiller indicated that there was a "Flow sensor 1" error.

While the laser was down I mounted a B&K voice coil shaker on the +X, +Y corner of the table to study the PSL jitter contribution to DARM noise in the 80-200 Hz region. I doubt it will affect alighnment but be aware since it is quite heavy.

BP

Following Friday night's lock, I looked at the spectrum and saw some regular structure, looking like a 2Hz comb at odd frequencies.This looks like a new comb. [figs 1&2]

As followe up, I ran coherence with all of the EBAY magnetometers and saw strong coherence is some places with this 2Hz comb, as well as the persisting 0.5Hz comb (see plots below)

0.5Hz comb: https://ldas-jobs.ligo.caltech.edu/~brynley.pearlstone/comb_investigations/May_2016_comb/H1:PEM-EX_MAG_EBAY_SEIRACK_Z_DQ_25_40Hz.png

0.5Hz comb + 2Hz comb: https://ldas-jobs.ligo.caltech.edu/~brynley.pearlstone/comb_investigations/May_2016_comb/H1:PEM-EX_MAG_EBAY_SEIRACK_X_DQ_25_40Hz.png

Note: These two are the same magnetometer (MAG_EBAY_SEIRACK), looking at 2 different axes. Both combs were also seen in other magnetometers.

Full list of plots: https://ldas-jobs.ligo.caltech.edu/~brynley.pearlstone/comb_investigations/May_2016_comb/

Previous efforts to mitigate the 0.5Hz comb was focussed on powering the timing card independently in the CS EBAY LSC-C! I/O chassis which handles DARM. This has not worked to eliminate the comb. I can't report any reduction yet, as Friday's lock was not sensitive at low (<100Hz) frequencies.

This 2Hz comb on 1Hz offset is the transform of a 1Hz square wave. The 2Hz comb might have to do with the 0.5s and 1s structure seen it Keith's data folding studies here: https://alog.ligo-wa.caltech.edu/aLOG/index.php

Evan, Sheila

Today we blended CHARD P, with the same blend filters Craig and I used last night for yaw. This went smoothly and the attached screenshot shows the settings, which are accepted in SDF and shouldn't need to be in the guardian since they don't need to change.  WE haven't made it to low noise to see what kind of improvement this gives us.

We also had a look at dithering SRM and demodulating DARM control to get an alignment signal for SRM.  The SNR was not good for a 4Hz or 9 Hz dither, but for a 15 Hz dither there is clearly a signal, although the lock point was not good. I've added filters we could try to supress the length coupling in MICH2, SRCL2, PRCL2 filter banks, but we didn't get a chance to try this again.

Evan noticed that there is an instability in CHARD P at 0.2Hz when we tried to power up past 20 Watts or so last night, so we redisgned the boost that comes on at 17Watts to be gentler and have higher frequency zeros, (the new filter is MSBoost2 and in FM1).  With this we seems to be stable at 30Watts, at least for 5 minutes (we broke lock by trying to go to 35W). 

We had a bit of trouble with the laser today, nothing that can't be fixed easily ( noise eater and ISS oscialltions, difficulty locking the FSS).  Evan changed the temp search ramp parameters for the FSS. 

1:30pm local

1/2 turn open on LLCV bypass --> took 33:17 min. to overfill CP3. 

Raised LLCV from 20% to 21%.