J. Kissel

[[[ EDIT -- The feature excited in the attached measurements is at 5.1 [Hz], NOT 6.1 [Hz]. I was reading the plot too quickly, had 6.1 [Hz] on the brain, and assumed it was 6.1 that I was ringing up. This 5.1 [Hz] feature is most certainly the last "transverse" mode (that has roughly equal components in L, R, and P as well), modeled to be at 5.08 [Hz].

Only configuration (3) shows anything at 6.18 [Hz]. In the other configurations, it is probably just that I'm only using one of two vertical sensors that excites roll motion -- which is NOT damped, because the R loop is open during these measurements.

Note, that this doesn't rule out that M0 LF has a problem. But it certainly makes concluding anything more complicated. 

Sorry for the confusion. Thanks to Dr. Lantz and J. McIver for reminding me how to read a logarithmic plot.]]]

Inspired by a suggestion of the good Dr. Lantz, I tried to further narrow down the source of the 6.18 [Hz] feature that has been plaguing H1 SUS ITMY. With the ISI still in it's best performing state, L,T,P, and Y SUS damping loops running, and the R loop off, I tried running the M0 (main chain) V SUS damping loops (which use the average of M0 LF and M0 RT OSEMs) with only M0 LF and only M0 RT OSEMs. I did this testing 5 different configurations:
(1) V loop open
(2) V loop closed with V to M0 LF OSEM2EUL element as zero (V to RT element at nominal -0.5, EUL2OSEM elements using both as nominal)
(3) V loop closed with V to M0 RT OSEM2EUL element as zero (V to LF element at nominal -0.5, EUL2OSEM elements using both as nominal)
(4) V loop closed with both V to M0 LF OSEM2EUL and EUL2OSEM elements as zero (V to RT elements at nominal -0.5)
(5) V loop closed with both V to M0 RT OSEM2EUL and EUL2OSEM elements as zero (V to LF elements at nominal -0.5)

Configurations (1), (2), and (3) are shown in the first attachment (*_0435_*.pdf), and configurations (1), (4), and (5) are shown in the second attachment (*_0521_*.pdf).

Configurations (1) and (4) did NOT show the 6.18 [Hz] feature, while configurations (2), (3), and (5) all showed the 6.18 [Hz] feature (plus various other mechanical modes and harmonics rung up as well). This directly points the finger at the M0 LF sensor/actuator.

Indeed, because the ISI input motion is so small, without the M0 LF OSEM in use, the *ENTIRE* spectra is limited by the expected OSEM sensor noise floor (see, e.g. configuration (1)). It's therefore blatantly obvious when the feature oscillates that it excites the whole suspension in many DOFs. If one squints, one *CAN* see the feature in all configurations, implying that wherever the source, it is visible in BOTH LF and RT sensors. In the configurations where the feature is not triggered into oscillation, it's only a factor a few above the noise floor, but it's still there. 

I'm not sure that this data set rules out the sensor, actuator, a nasty cross-coupling, or something else inherent to the motion of the suspension, but at least it narrows down the oscillation problem to one rogue OSEM.

Please swap out the M0 LFRT, R0 LFRT satellite amplifier tomorrow, and we'll test whether the feature disappears.

I removed the temperature/relative humidity probes from the dust monitors in the OSB optics lab, vacuum prep lab and bake oven room. I also power cycled each dust monitor after I removed the probe. Ever since these were added there were constant intermittent communication errors with these dust monitors.

This closes work permit 4130.

After figuring out that the 6.18Hz was coming from the vertical loops of M0 (The left OSEM doesn't behave properly), spectra and transmissibility transfer functions were measured with the following configuration:

-  HEPI with position control (100mHz UGF)
-   Feedforward HEPI L4C to stage 1
-  Stage 1 blend

o   750mHz in Rx, Ry, Rz
o   100mHz with notch at 440mHz in X
o   40mHz with notch at 440mHz in X

-  Stage 2 blend

o   750mHz in Rx, Ry, Rz|
o   100mHz with notch at 440mHz in X and Y

-  Level 3 controllers

o   Stage 1 – 40Hz
o   Stage 2 32-35Hz

-  SUS damped except on M0 in Roll and vertical
-  No sensor correction

Spectra presented were measured at 1062915770 (start time) during 45 minutes. Spectra in all DOFs are presented in attachment. Performance is great.

Transmissibility transfer functions are measured while driving white noise on the HEPI actuators. Two transmissibility plots are presented. In the first one, the transmissibility is computed using the HEPI L4C as input.

In the second one, the transmissibility is computed using the HEPI excitation and the supposed input motion is calculated (alog https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=7692)

It is important to note that:
-  The isolation filters of the BSC-ISI were designed with the HEPI locked
-  These loops are stable and robust in time. There were closed few days.

One of requirements of the ALIGO optical levers are to perform as well or better than their ILIGO predecessors in terms of sensitivity and their respective resonances.  I'm not sure of the state of the ILIGO optics during the measurement, but for ALIGO, we had the suspension damping loops running, the ISI damped, and HEPI locked.   Attached are 4 graphs comparing the ITM and ETM spectra from the LHO HIFO-Y test to Kate Dooley's spectra from ILIGO.  Both sets of data were calibrated to uradians so they should be directly comparable: 

- First off, we see that the sensitivity at frequencies >2Hz, the ALIGO sensitivity is better or the same in pitch for both ITM and ETM but yaw is not as good; the noise floor for ITMY pit is due to the ADC noise floor, as is true of the rest of the OL signals, but the other DOFS don't quite get down to that level of sensitivity till ~20Hz, this should be improved.  It looks like the noise is dominated by electronic that is ~1/f dependence, most investigation is needed.

- The good news is that the first resonances of the ILIGO piers occur at ~21Hz whereas the first ALIGO resonances that come from the pier peak at ~31 Hz, and keep in mind that this is done without grout which shown in ALOG 7746, will help push the resonant peaks higher in frequency.

Robert Schofield, Thomas Vo

While looking at ITMY spectra from HIFO-Y of the optical levers, we saw that the first pier resonance occurred at ~31Hz, which was caused by the transmitter.  The real question was whether or not this peak is due to rigid body motion or if it's from flexing/vibrations in the pier.  This is important because the piers are not yet grouted and if the resonances are from rigid body motion, then grouting will help but it wouldn't help the vibrations and flexing of the pier as much.  So we set up a little experiment to see if grouting will help this particularly troublesome 31Hz peak.

First we used an accelerometer and took spectra as is, with only three bolts holding up the pylon, then we added 4 machine jacks to help support the pylon, much like grout would do.  Attached are pictures of the two setups, and spectra showing that the 31Hz peak shifted up 50 Hz after adding the machine jacks, yay.  Of course, we'll repeat a similar measurement when grout is in place.

K. Izumi, M. Barton [J. Kissel as moral support and scribe]

    Bolstered by my bold claim of stable H1 IMC locks last night, Mark began launching MC2 violin mode measurements. However, the lock stretches were not long enough to get a full ring-down. My unsubstantiated claim yesterday was air-currents in the PSL were the source of lock losses (see LHO aLOG 7736), but Kiwamu identified it to be low frequency excursions that saturated the MC2's M3 stage drive -- by normal control that should be adequately offloaded to the upper stages of MC2. 
    Why? Two days ago, during Keita's attempt at debugging the IMC (see LHO aLOG 7724), he had modified Stefan's auto-locker (MClockwatch) to use the smaller gains he'd found to be stable. We had forgotten this yesterday, among all the other things wrong. Further, after triple-checking against the known filter configuration (from LLO aLOG 7974), we found FM4 (a [z:p] = [1:100] filter) in the M2 LOCK L bank had been disabled some time during this recent week of guardian commissioning / problem solving (who knows why or by whom, doesn't matter). We've restored the correct gains into MClockwatch, and engaged M2 LOCK L FM4, and the H1 IMC has been locked ever since.

NOW the H1 IMC is back to full awesomeness. MClockwatch is running on opsws5. PSL is still in commissioning mode.

As a reminder, the length loop settings in this configuration are
During Lock Acquisition

H1LSC     H1:IMC-L                = FM1 (antiWhite) * G = +1.0

H1LSC     H1:LSC-MC               = FM10 ( :0.3) * G = +1.0

H1SUSMC2  H1:SUS-MC2_M3_ISCINF_L  = (no filters, G = +1.0)
          
          H1:SUS-MC2_M3_LOCK_L    = FM3 (150:40) * FM9 (CLP300) * G = -300
          
          H1:SUS-MC2_M2_LOCK_L    = FM4 (100:1) * FM10 (ELP70) * G = 0

          H1:SUS-MC2_M1_LOCK_L    = FM2 (0.1.0.01) * G = 0


While Locked:

H1LSC     H1:IMC-L                = FM1 (antiWhite) * G = +1.0

H1LSC     H1:LSC-MC               = (no filters, G = +1.0)

H1SUSMC2  H1:SUS-MC2_M3_ISCINF_L  = (no filters, G = +1.0)
          
          H1:SUS-MC2_M3_LOCK_L    = FM3 (150:40) * FM9 (CLP300) * G = -300
          
          H1:SUS-MC2_M2_LOCK_L    = FM3 (0.1:1) * FM4 (100:1) * FM10 (ELP70) * G = +0.2

          H1:SUS-MC2_M1_LOCK_L    = FM1 (0:0.01) * FM2 (0.1.0.01) * G = +1.0

This week a number of flatbed semis delivered all of our roofing material. The traffic jam lasted about a day. Yesterday, after offloading the trucks, materials were hoisted up onto the end and mid station buildings. Today the crew is busy loading the LVEA roof with the materials. The crew plans to work 4 ten hour shifts as they are based in Spokane. Monday they will be back to start at the ENDX station.

Richard relocated the corner station antennae which were mounted on the weather station tripod to their temporary location on the conduit goose-necks. This clears the roof in preparation for re-roofing work. The GPS antenna for the timing master was already located on the conduit, and was only affected by the local activity (see attachment). The NTP antenna was disconnected during the move. The receiver in the MSR was not powered down and it recovered satellite tracking very quickly (less than a minute).

We learnt that any work close to the master antenna can cause loss of tracked satellites especially if the antenna is touched.

K. Izumi, J. Kissel, P. Thomas, C. Vorvick

The H1 IMC is back to stable, many-minute lock stretches with good alignment, with all LSC and ASCIMC loops running as designed (using all three stages of MC2 for length control), and the HAM2 and HAM3 isolation systems performing at their best thus far (HPIs floating with alignment offsets, ISIs at Level 3, and SUS with old Level 1.5 damping loops). It was a long battle because many things were wrong with ISC/IOO side of things, but Kiwamu and I think we've managed to put the whole picture together, which is outlined below. Note, that this covers some of the material found in Cheryl's earlier entry, so see LHO aLOG 7229 when referenced. The PSL is still in commissioning mode -- we know that's what's causing the high-frequency intensity noise (as seen on the MC REFL camera), and may also be the cause of the occasional lock losses. The simple (non-guardian) MClockwatch auto-locker is currently running on opsws5.

-----
The Problems
-----
(Here's what we've fixed:)
- The power outtage from this past Thursday (LHO aLOG 7646) look down all front ends, but -- most important to this story -- the imcasc frontend. This frontend controls the Periscope PZTs that steer the IFO beam from the PSL into the IMC. These PZTs are known to have terrible hysteresis, such that even if you burt restore their alignment settings to a known good time, you're not guaranteed that the same alignment returns. This is what happened here.
- Slowly, over the course of days, the alignment of the mode cleaner appeared to decay. This was because the MCWFS loops (in particualr DOF 3 which uses those same PZTs as actuators to control the input beam pointing) were slowly steering the input beam to a bad place. Eventually, the PZTs had been steered so much -- and the mode cleaner's integrators followed enough -- that light fell off MCWFSA and B. This meant that any attempts WFS control would fail. Also, or perhaps more probably, the MC WFS alignment offsets had been offloaded a few times, but offloaded with worse and worse alignments.
- Until this afternoon (as Cheryl mentions in 7229), we had forgotten to restore the H1 LSC front end epics. The LSC front end contains not only the H1:IMC-L filter bank and the H1:LSC-MC filter bank, but also the LSC-MC_FM_TRIG_THRESH channels which define the point at which to turn off a 3[Hz] low pass in FM10 of the H1:LSC-MC filter bank. These thresholds *had* been set to zero, so this extra low-pass filter (designed to let the IMC swing through a few fringes/FSRs before locking, so it doesn't lock on a non-00 mode) remained in the length path, distorting the frequency-dependence of the loop gain, and therefore causing the loop to go unstable.
- (Our best guess), In one of the MC WFS scripts that was mistakenly run (see 7229), the ASC IMC loops were turned off in a hidden place -- the input to actuator output filters (e.g. H1:IMC-MC1_PIT_INPUT, H1:IMC-MC3_YAW_INPUT, etc) which are not shown on the overview screen. We created a successful work-around for a while, but discovered this at the very last minute (see solutions story below).
- The screens for the MC WFS output matrices were full of copy-and-paste errors, such that both PITCH and YAW screens were labeled as "PITCH," and even some calls to matrix elements from PITCH were found in the YAW matrix.

(The following is still wrong/broken/incorrect, but doesn't seem to matter:)
- The PSL is in commissioning mode, with HEPA fans still blowing around and room lights on inside the enclosure. Not Tragic.
- The PZTs that control the beam-steering onto MCWFSA and MCWFS B are non-functional. We did all of the  WFS centering by going into IOT2 and manually tweaking the knobs of the mirrors. Kiwamu says that Shiela was in the middle of debugging this, which we (Kiwamu and I) think is a problem with the Beckhoff computer. Thankfully we can still operate the knobs manually.
- The MC2 TRANS QPD's analog whitening filters are somehow busted -- when engaged the TRANS signal goes negative. Yuck. Strangely enough, the only stable configuration we've found with all analog filters OFF, but ONE of the digital compensation filters ON, as though the IMC WFS DOF3 loop was designed with this configuration. Double Yuck.

(The following definitely doesn't matter, but are things I noticed along the way that NEED to be fixed to improve the interoperability SEI/SUS systems)
- The SEI/SUS IOP Watchdog blocks the output to HEPI, but DOES NOT trip it's internal watchdog system. Hence, when you reset the IOP watchdog all output remains (which is currently only actuator basis alignment offsets; isolation loops are not-yet-commissioned), and you send a jolt to the chamber. Thankfully, the alignment offsets were small this time. 
- The HAM-ISI checker script is still not yet functional. So in order to reset the HAM-ISI watchdogs, you MUST use the "turn off isolation loops for HAM(2/3)" script to ramp down the other-wise-huge output of the isolation filters. If not, the watchdog will just happily keep cycling through the states, laughing at you, and calling you silly for trying to reset the watchdog when the output request is 532 billion.
- I'm not sure how the ISI's blinky performance matrix was copied the to IMC OVERVIEW screen, but its matrix elements' color schemes DO NOT match up what's in the top middle of the HAM-ISI OVERVIEW SCREEN. What's worse (who cares about the color scheme), is that the matrix elements BLINK DIFFERENTLY. What appears to be a completely happy, stable, meeting-or-beating-requirements matrix on the ISI screen, looks like a constantly fluctuating ISI (flashing BLUES and PURPLES) on the IMC OVERVIEW screen. I've checked, and the matrices are looking at the exact same channels, but it seems as through whomever copied them over to the IMC screen CHANGED THE THRESHOLDS on the MEDM screen or something. I haven't looked at in any more detail.

----------
The Solutions
----------
(Note, during entire problem solving stage, MClockwatch was running in the background, grabbing the length lock whenever it could.)
- Now stuck with a new alignment of the input beam from the PSL because of the hysteric (intentional typo) periscope PZTs, Cheryl, re-aligned the MC1, MC2, and MC3 suspensions to maximize MC_REFL (as mentioned in 7229). The new alignments are

      P      Y  [urad]
MC1  +314   -984 
MC2  +428   +251
MC3  +237  -1079

- Kiwamu found the bug with the with MC TRIGGER thresholds, and restored them to a reasonable value:
H1:LSC-MC_FM_TRIG_THRESH_ON  = 1000
H1:LSC-MC_FM_TRIG_THRESH_OFF =  900
- Kiwamu also fixed the MC WFS output matrix MEDM screen bugs.
- Kiwamu and I manually re-centered the MC WFS to at least get the beam back onto their PDs. 
- Kiwamu started up the MC WFS loops' DOF 1 and DOF 2 (which use the MC Suspensions to align the IMC waist). Now with light on the MC WFS, the loops were completely stable as normal.
- Kiwamu tweaked the input beam alignment by (digitally) adjusting the PSL Periscope PZTs, using the P & Y signals on the MC2 TRANS QPD as the figure of merit. He made sure to do this slowly enough that the MCWFS DOFs 1&2 could follow and pull along. 
- Kiwamu tried to turn on DOF 3, but found it pulling the IMC out of alignment, eventually to break its lock. A discussion of the output matrix led him to zero out the DOF 3 contributions to MC Suspensions, and leave it only actuated by the PSL Periscope PZTs. In this configuration, with all three DOFs closed, we were able to get nice long lock stretches.
- Kiwamu offloaded, or "relieved" the DC offsets in the MCWFS  loops' error points into offset field of the MCWFS DOF actuator output filters (e.g. H1:IMC-MC1_PIT_OFFSET, H1:IMC-PZT_YAW_OFFSET, etc.), using 
${userapps}/ioo/h1/scripts/imc/mcwfsrelieve
(At this point, the mode cleaner is at the ideal locking alignment)
- Kiwamu went out and re-centered the MC WFS to this newly-ideal alignment (with all IMC L and ASC loops running), but while out there, he noticed the input to both MCWFS PZT actuator output filters (H1:IMC-PZT_PIT_INPUT, H1:IMC-PZT_YAW_INPUT) were OFF. Our best guess is that one of the defunct scripts that was run earlier turned them off. This explained why DOF 3 was going unstable with the nominal output matrices -- the DOF 3 was trying to actuate on the PSL Periscope PZTs, but was only getting action from the MC SUS's.
- Finally, Kiwamu turned ON these inputs, and restored the output matrices, and declared victory. 


*phew* Can anyone say "Configuration Control Nightmare?" I sure can.

Cheryl V., Jeff K., Kiwamu I., Patrick T. working on MC locking (alog 7729)
ARK staging roofing materials (WP 4126)
Apollo moving clean room in the LVEA (WP 4125)
Continuous communication problems with dust monitor 15 in the LVEA
One of Dale's students filing sharp edges off piece of old beam tube near the warehouse

09:00 Corey G. going to take pictures in the squeezer bay
09:17 Arnaud P. running transfer functions on TMSX
09:24 Andres & Jeff B. going to work on ITMX
09:47 Dave B. rebooted the DAQ to add GPS coordinates to the frame files
10:34 Andres & Jeff B. going to work on ITMX
12:37 Andres & Jeff B. going to work on ETMX
13:27 Thomas V. going to work on assembly baffle
14:50 Andres & Jeff B. back from end X
15:24 Arnaud P. going to LVEA to take hammer test measurements on cage of ITMX

  Andres & Jeff

  We installed the vibration absorbers, upper structure cross braces, and wafer holder on ETM-X. This completes the payloading for this suspension.   

   Andres & Jeff

   We installed the vibration absorbers on ITM-X. This completes the payloading for this suspension. 

This morning Arnau ran another set of Transfer Functions for the H1 TMS EX, and after the measurements he gave the "GO AHEAD" that the system looked good to go.  So, after SUS crew did work installing Vibation Absorbers, I went about staging ALL (6) TMS cables in coils on the ISI's Stage0.  They now await Jim to dress them on the ISI.

Notes

• Yesterday during cable testing, we discovered that the Green QPD's cable connector which connects to the BSC9 feedthru is missing set screws (so it can't be screwed into the feedthru).  We'll probably try to fix this in-situ.  This cable is D1000924 s/n S1104104 (as noted in table, here).
• Size #18 caddis fly (i.e. a flying bug!) was observed on the ETMx quad (on cyllinder of penultimate mass).  Jeff tried shooshing it away, but it ended up flying upstairs and we lost track of it.

Attached are plots of dust counts requested from 4 PM September 2 to 4 PM September 9. Each plot is 1 day.

- Patrick, Cheryl, Jeff, Kiwamu 

Morning spent with Patrick and I investigating IMC poor locking, i.e. only brief locks.  Keita started us on the issues of too much gain on H1:SUS-MC2_M2_LOCK_L_GAIN, which he changed form 0.2 to 0.008, in order to get any locking last night. 

Looked at Stefan's autolock script and the channels it changes, and all was OK. Compared MC Common Mode channels/settings, all was OK. 

Tracing the GAIN path backward, I found we could lock with autolocker settings and MC2_M2_LOCK_L_GAIN at 0.2, if I lowered the overall MC2 LSC gain from 1.0 to 0.15. 

Jeff joined us, we burt restored h1lscepics and MAGICALLY the IMC locked with the MC2 LSC gain back at 1.0!  Somehow that fixed the gain issue, though we have not located the exact setting that changed.

At this point Jeff reenabled HAM2 ISI and set it to Level 3 isolation. This helped with 1Hz oscillation seen in REFL. Then we set HAM3 isolation to Level 3 from Level 2, and further decreased the 1Hz noise. This allowed for a long lock and I was able to align manually to get REFL down to 240 and MC TRANS around 2200.

We tried to engage WFS, but found it driving the lock to a bad place, REFL = 800. Kiwamu arrived, and is now working on WFS.

WFS are not well aligned, and MC2 TRANS QPD is high in pitch.  This means the IMC alignment is good for REFL, but not for the IMC as a whole, which could be my alignment changes to MC1, or changes in the PSL input beam pointing from PZT's being turned off and on yesterday (see NOTE), or changes to the PSL input beam pointing from temperature change made by Rick in the PSL enclosure, or all 3 combined.

NOTE... I ran scripts attached to the WFS medm screen yesterday, which apparently have NEVER been run here before, and were written at LLO.   Why do we do this to ourselves?  I was telling Jeff the script to turn off ASC turns off the PZT offsets WHICH SHOULD NEVER BE TURNED OFF!!!  Now I learn from Kiwamu that no one has ever run any of those scripts at LHO.  Are these scripts even used at LLO?  This sort of thing is a death trap for an IFO.

Currently Kiwamu is working of WFS.

Sebastien, Jim

We are currently testing the BSC-ISI unit #6 in the staging building. The 2 stages are unlock and balanced, everything seems to be well connected.

The power spectra show something wrong on GS13-V1 and GS13-V3 (see figure attached).

After further investigation, the issue seems to be 2 bad cables. They will be change tomorrow.

We're done with in-vac cable test.

Tomorrow Corey needs to re-rout the cables on ISI back to the intended position (i.e. closer to the real feedthrough).