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Reports until 23:04, Tuesday 26 May 2015
H1 SUS (CDS, SUS)
sheila.dwyer@LIGO.ORG - posted 23:04, Tuesday 26 May 2015 - last comment - 10:36, Wednesday 27 May 2015(18640)
ITMX PUM AI chassis not working

Evan, Kiwamu, Sheila, Jeff

We noticed that we weren't really driving ITMX PUM.  Evan and I went to the racks and saw that the DAC outputs were changing, but the LED that says DAC WD next to the DAC input was not lit and there was nothing coming out of the AI board.  This is probably why Dan was unable to damp ITMX violin modes last night.

Comments related to this report
sheila.dwyer@LIGO.ORG - 23:46, Tuesday 26 May 2015 (18641)

h1susb123 has stopped running, the symptoms are verry similar to what happened yesterday.  There are several red block on the CDS overview screen, front end models are not synced to the IOP. 

This coincided with kiwamu pulling out the AI chassis for ITMX L2, although we aren't sure if this is related or not.  We don't know how to restart this without causing a problem for the dolphin network, so we're done locking for tonight. 

daniel.hoak@LIGO.ORG - 00:41, Wednesday 27 May 2015 (18645)

AH-HA!

filiberto.clara@LIGO.ORG - 10:36, Wednesday 27 May 2015 (18649)
Replaced the 18-bit DAC Anti-Image interface board (possible bad optocoupler) for AI Chassis S1103818.
 
Board removed S1103833
Board installed S1105351

Chassis was reinstalled and powered up. Verified both DAC WD LED's were on.
H1 CAL (AOS)
jeffrey.kissel@LIGO.ORG - posted 21:39, Tuesday 26 May 2015 (18639)
Cal Team Day 1 Debriefing
D. Gustafson, K. Izumi, S. Karki, J. Kissel, R. Savage, D. Tuyenbayev

Stay tuned for more details on each, but since we have so little time during these three days we're taking the "take the measurement now, look at it enough to know *you're* happy, *then* think and document it once we don't have any more time" approach, so please be patient if our aLOGging falls behind our activities. As such, I'm going to try and keep up with this daily "debriefing" so at least all are aware of our progress.

We've begun this week's calibration measurement's by doing the most invasive stuff first:
K. Izumi, D. Gustafson 
     - Made electronics measurements necessary to use the ALS DIFF VCO as a calibrated frequency actuator and compare line(s) generated by this VCO against ESD calibration lines in the DARM ASD to assess QUAD's actuation strength. See LHO aLOG 18634.

J. Kissel, R. Savage, S. Karki, D. Tuyenbayev
     - Made SR785 measurements of all elements of the EY PCAL electronics chain, including the AA, AI, and full RX (reflection off of the test mass PD) and TX (a PD picking-off of the power transmitted into the test mass) that includes the PCAL interface chassis, similar to what has been done at LLO (see, e.g. LLO aLOGs 18106, 18199, 18309).

Goals for tomorrow:
K. Izumi (and whomever's willing to help)
     - Get a free-swinging Michelson measurement of all stages of the ETMY's actuators that are involved in the hierarchy

J. Kissel, S. Karki
     - Finish straight-forward electronics measurements for ETMX PCAL (i.e. the same that were done today at EY)

R. Savage, D. Tuyenbayev
     - Stay at EY and compare PCAL PDs against other broad-band PDs to assess frequency response of PCAL PDs.
H1 AOS (CAL)
richard.savage@LIGO.ORG - posted 18:45, Tuesday 26 May 2015 (18638)
Pcal temporary test at Yend

For an overnight test we have moved the Rx detector assembly into the Tx module and directed both output beams into the detector.

We plan to restore the nominal setup tomorrow morning.

Note that the cover on the Tx module is ajar while we are making this measurement.

H1 CDS (DAQ)
david.barker@LIGO.ORG - posted 18:04, Tuesday 26 May 2015 (18637)
Maintenance Summary

I reviewed front end code which have outstanding local mods. I committed to SVN h1alsex.mdl, h1alsey.mdl, h1iopsusauxex.mdl, h1iopsusauxey.mdl, h1iopsusex.mdl, h1iopsusey.mdl. Files which still need committing: ASCIMC_MASTER.mdl, lscimc.mdl and CD_STATE_MACHINE.c

I "greened" up the IOP SDF by switching the DAC Duotone OFF on h1lsc, h1iscex, h1iscey.

I ensured filtermodule file synchronisation by pressing the  LOAD_COEFF buttons on all models.

I verified all safe.snap files in the target areas are symbolic links to userapps, and checked in local mods.

I'm in the process of ensuring all filter module files are symbolic links to userapps (12 were not) and checking these into SVN. COEFF_LOAD is needed when the file is changed from local to symbolic link to clear the "modified file" message.

I copied the latest Beckhoff DAQ INI files to the DAQ. I had to remove the duplication of the H1:PSL channels as was seen before. The DAQ was restarted after this morning's model changes.

The IRIG-B excursion of h1seih45 following its power supply swap took several hours to come back down. The CDS Overview is now GREEN, any non-GREENs should be investigated.

H1 PEM
james.batch@LIGO.ORG - posted 17:52, Tuesday 26 May 2015 (18636)
Restarted weather station IOC for EX, MX, and MY
Dave, Jim

Weather station IOC's failed at EX, MX, and MY during lightning and heavy rain.  Restarted IOC's, set alarm levels.
H1 SEI
thomas.shaffer@LIGO.ORG - posted 17:31, Tuesday 26 May 2015 (18635)
BRS Active light added to ISI EX GND medm

Do you often wonder if the BRS on or off? Do you stay up at night asking yourself if you should have turned it off when someone went down to EX?

Ask no more! There is now a BRS Active light on the ISI EX_GND medm screen.

Operators: if someone is heading down to EX, please make sure to check that the blue "Not in use" light is lit. If it is not and the brighter blue "ACTIVE" light is, go to the wiki:  https://lhocds.ligo-wa.caltech.edu/wiki/UsefulScriptsForOperators  and follow instructions to turn OFF the BRS sensor corrected signal.

 

An important thing to note: this medm light does not look at the sensor correction filters, only if the appropriate matrix elements are selected. This should not be a problem since the script turns on the correct filters when switching between using the BRS sensor corrected signal (ON) and not using the BRS signal (OFF). In the near future, a Guardian node will control this rather than scripts from the command line and, hopefully, eliminate all confusion.

 

A screenshot is attachted of the "Not in use" light.

Images attached to this report
H1 CAL (CAL, ISC)
kiwamu.izumi@LIGO.ORG - posted 16:47, Tuesday 26 May 2015 (18634)
ALS DIFF VCO freq-volts calibration measured

Dick, Kiwamu,

We measured the volts-frequency relation of the ALS DIFF VCO by closing the ALS diff VCO PLL. We will upload the data and results later.

In order to measure the VCO response, we discconnected the DIFF beatnote from the phase-frequency discriminator and temporarily hooked up an IFR 2023A to simulate a clean signal. After we finished the measurement, we reconnected the beatnote cable back to the phase-frequency discrminator.

H1 General
nutsinee.kijbunchoo@LIGO.ORG - posted 16:09, Tuesday 26 May 2015 (18631)
Ops Summary

8:20 Peter and Ed to PSL enclosure. Lock loss right after.

8:22 Joe take the pesticide guy into the LVEA.

8:35 Kyle to EY. Pump RGA.

8:39 Joe out

        Kris and Karen to LVEA

8:45 Elli & Nutsinee to HWS table near HAM4

8:39 Jason to PSL enclosure

9:00 Elli and Nutsinee out

9:40 Dick to ISC rack 2,3 to measure ground noise

9:48 Fil to EY and EX rack

9:52 Patrick back up database

10:32 Kyle to LVEA

10:48 Kyle out

10:53 Karen and Kris leaving EX, heading to EY

11:14 Richard & Jim swap power supplt SEI 4,5 (HAM4,5 brought to OFFLINE)

11:22 Jeff K. to EY moving binary IO cabel

11:26 Jason et al. out of PSL enclosure

11:40 EX Beckhoff restarted. Burtrestored to 06:10

11:43 Kiwamu and Dick to ISC rack. Disconnecting ALS diff PLC.

          Jeff K. leaving EY. Dave restarting DAC.

11:46 Kris and Karen leaving EY

11:49 DAC back

11:53 Patrick done with the back up

11:58 Jeff K. bringing ISI EY back

11:59 Gerado to EY

12:15 Gerado and Kyle back from EY

12:53 Dick and Kiwamu back

13:15 TJ to EX restarting BRS

13:30 Richard to compression room EX

13:45 TJ back

13:50 Richard back

14:01 Dick and Kiwamu to ISC rack

14:14 Jim and TJ to EX - restarting BRS (again)

14:36 Jim & TJ back

           Dick & Kiwamu back

15:35 Jason & Ed to ETMX OPLEV

15:44 Rick, Sudarshan, Darkhan, and Jeff K. to EY (Calibration work)

16:09 Jason and Ed back

 

Happy Maintenance Tuesday....

H1 SUS
betsy.weaver@LIGO.ORG - posted 16:07, Tuesday 26 May 2015 (18633)
ETMy SDF diffs over the weekend - ETMy may or may not be in configuration

Just a heads up to commissioners:

I took a snapshot of the ETMy SDF diffs that popped up over the weekend of commissioning this morning.  After Kissel's model fix from this morning, the diff list is smaller now.  This may imply that some of the purposeful changes made to ETMy over the weekend have been undone -  it is hard to tell because many of the things that were on the larger diff list from before the reboot were people likely "just testing" things that weren't working over the weekend.  Or, there are some settings guardian is switching since we're not back up and lots of testing is taking place right now (meaning, I haven't caught them all and made SDF ignore them yet).  Or, the reboot and sweep through the GRD SAFE-DAMp settings cleared house.

In any case, I post the before and after list in the event ETMy still is not acting properly for the evening commissioners and they are looking for "previous" settings..

Images attached to this report
LHO VE
kyle.ryan@LIGO.ORG - posted 15:33, Tuesday 26 May 2015 (18632)
Added shims to CP2 LLCV to gaurantee minimal flow through transfer line while PID loop adjusts to today's overfill
Praxair delivery today resulted in CP2 overfill -> PID loop will eventually shut-off LN2 flow through transfer line as a response -> Warm transfer line will likely result in secondary under fill alarms tonight -> shimming LLCV slightly open will keep transfer line cold regardless of PID output to LLCV 
H1 SEI
thomas.shaffer@LIGO.ORG - posted 14:54, Tuesday 26 May 2015 (18629)
BRS Restart

Jim W., TJ

SYS_DIAG reported that BRS had flatlined, and after looking into it it looked like the software crashed on Saturday (attached image). The BRS is not currently being used for sensor correction so this was not a big deal but we did need to restart it. I took a trip down to EX, followed the instructions on Alog 13817, drove back and realized that that had not corrected the problem. I took Jim with me this time and he noticed that the rate box on the running analysis screen was empty. He restarted it again and it all seemed to work well. Everything looks good now.

Images attached to this report
H1 CAL (CDS, DetChar, ISC, SUS)
jeffrey.kissel@LIGO.ORG - posted 14:30, Tuesday 26 May 2015 (18628)
Precision Transfer Functions of H1 SUS ETMY AI Chassis
J. Kissel

Another belated aLOG: I've measured the ETMY AI chassis this past Wednesday morning in an identical fashion as to how I'd measured ETMX in 18518. See attached set of plots, but more importantly fo use later, the data lives in 
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER7/H1/Measurements/ElectronicsMeasurements/H1SUSETMY_L1_*.txt
which has been processed by 
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER7/H1/Measurements/ElectronicsMeasurements/process_H1SUSETMY_AI_Measurements_20150520.m

As with ETMX, all relevant AI chassis channels on M0, L1, L2, and L3
- are fully functional,
- have a "DC" gain of 0.9902 +/- 0.0001 [V/V] gain (measured at 10 [Hz])
- have a notch frequency of 65838 +/- 277 [Hz]
- drop to 0.976 [V/V] in magnitude and lose 27 [deg] in phase (again no surprise).
These measurements will be used to inform the calibration model, as opposed to what we're currently using which had been the mean and std of several hundrend generic AI/AA filter boards that had been tested (and done so prior to the -v6 upgrade). That being said, there's very little difference between the two, so there will be little to no change.


Non-image files attached to this report
H1 SUS (CDS, DetChar, ISC)
jeffrey.kissel@LIGO.ORG - posted 14:11, Tuesday 26 May 2015 (18622)
Binary IO Fixed for H1SUSETMY's new Low-Noise ESD , and now independent fron TMSY; Tidal Path Bug Fixed
J. Kissel, D. Barker, J. Batch, R. McCarthy, R. Abbott

First: Thanks to all that aLOGged / documented what we had installed / debugged for the new low-noise ESD driver in my absence, (i.e. LHO aLOGs 18559, 18592, 18568). Apologies for not having time for the true systems level check-out and not committing my work!

Second: The messages -- 
(a) The new BIO control and monitoring for the low-voltage ESD driver at H1SUSETMY is now independent of the H1SUSTMSY's BIO. To do so, we had to move the Binary Input and Output cables two ports "up" from channels 16-23 & 24-31 (as originally designed in D1400177-v4) to channels 32-39 & 40-47, and change the front-end code mapping in the h1susetmy.mdl model accordingly.
(b) I've fixed the bug which mapped the IPC error rate signal for the Tidal Correction into the main "library" block. It's now feeding the actual signal to the main library block as one might expect.

Details
--------
I've installed new infrastructure to support the BIO monitoring and control of switches inside the new low-noise ESD driver. Mostly* following the drawing shown in D1400177-v4, the driver has five groups of functions that are controlled and monitored: (follow along with the block diagram D1400301)
(1) HI VOLT DISCONNECT: there are four (one for each ESD quadrant) independently switchable relays on the input (marked as S1, S2, S3, and S4) that either engage the High Voltage ESD driver, or ground that connection and only use the Low Voltage Driver
(2) Low-pass filter switching (STATE REQUEST on the BIO MEDM screen): again four (on for each ESD quadrant) independently switchable relays to engage a z:p:k = [ 50,50 : 2.2,2.2 : 1 ] low pass filter (for more accurate description of poles and zeros, see the now-measured transfer function LHO aLOG 18579). 
     State 1 : Low Pass OFF
     State 2 : Low Pass ON
     [Bonus states, as with any coil driver: State 0: ISC control (currently terminated); State -1 or -2: same as above but use has control over digital compensation filters]
(3) HI/LO VOLTAGE: four, independently switchable relays  toward the output of the driver that select using the output of the High Voltage driver or bypassing it entirely (if the HI VOLT DISCONNECT is switched to DISCONNECTED). 
(4) RIGHT / LEFT PI SWITCH: For the not-yet commissioned parametric instability path (whose control signal will eventually come from an independent front-end model running at 64 [kHz]) one can independently chose whether to drive the upper or lower quadrant of the LEFT and RIGHT sides.
(5) HV ESD DRIVER TRIP RESET: This functionality should match the functionality of the red button on the front of the High Voltage driver -- when the driver trips, this is its momentary RESET button.

All of these switches are controlled via Binary I/O in the h1susetmy. They're packed up into a 16-bit word that gets fed to the binary IO card (see the generation of this word in 
2015-05-26_H1SUSETMY_BIO_L3.png). Note that for the low-pass filter switching (STATE REQUEST on the BIO MEDM screen) I've created a new sub-function to
/opt/rtcds/userapps/release/sus/common/src/CD_STATE_MACHINE.c
which is basically identical to the TOP driver's function, but without a test-coil enable, because it's a similar two-state machine (a state machine diagram will be added to T1100507 in the fullness of time).

Problem (a) was a result of piping this 16-bit control word into the "upper" half (bits 16-31) of the "lower" 32 bits (bits 0-31) of the 2nd (Card "1") of the h1susey 64-bit binary I/O cards, which is what the TMSY was already using to control its TOP mass coil driver switching (who was using the "lower" half, bits 0-15 of that same "lower" 32 bits of the 2nd card). Recall that the RCG must artificially split the 64-bits into two 32-bit words (the "lower" (0-31) and "upper" 32 (32-63), referred to as L32 and H32, respectively). However, it turns out that two front-end models cannot share one of these upper or lower halves, even though in analog land one might suspect that one might even be able to break the card up into even 8-bit word chunks. Thankfully the BI and BO chassis have virtually all of their spigots free, so we just shifted the cables "up" so that they came in on the "upper," H32 "card" and modified the front-end code accordingly to match (see 
2015-05-26_H1SUSETMY_SimulinkModel.png, and please forgive the mislabeled BIO ENCODE spigot that says it's still outputing the "L32" bits. This is an inconsequential remnant of the bug fix that I only noticed while writing this log, and I don't want to 4-R the front-end code just for a label fix.)

Problem (b) was just a byproduct of my haste in getting these front-end changes done. While cleaning up the top level of the model, I just misconnected the new FLAG / TAG for the tidal servo signal to the IPC error rate. Sorry about that.

-------
The following has been committed to the userapps repo (recall the top level, main control system part of model is *already* unhooked from the library because of how tidal corrections have been implemented):
/opt/rtcds/userapps/release/sus/h1/models/h1susetmy.mdl  SORRY FOR NOT DOING THIS EARLIER!!
/opt/rtcds/userapps/release/sus/common/src/CD_STATE_MACHINE.c 

The following has be consciously NOT committed to the repo (because it will conflict with changes already made to support ECR E1500228):
/opt/rtcds/userapps/release/sus/common/medm/quad
SUS_CUST_QUAD_OVERVIEW.adl
SUS_CUST_QUAD_BIO.adl
 
Images attached to this report
H1 SUS
betsy.weaver@LIGO.ORG - posted 13:51, Tuesday 26 May 2015 (18617)
On-going cleanup of SDF

1)  Found that the ETMx misaligned offsets were changed at 9am on Monday morning.  H1:SUS-ETMX_M0_TEST_P_OFFSET went from -107 to -307 suspiciously.  The YAW offset only changed by 10e-3 which is negligable.

No alogs as to why, and Kiwamu agrees that they should be set back to what they were last week.  Since the decimal places went out to the 10e-8 place unnecessarly, I've rounded to 10e-1.

2)  I zeroed a bunch of large +/- 20000 offsets that were loaded (but not turned on) in the ETMY COILOUTF OFFSETS.  Also, un-alogged as to why they were there - likely testing left over from last week??

3)  Ignored new DAMP MODE TRAMP channels all ETM/ITMs.

4)  Accepted new weekend DAMP MODE filtering on ETM/ITMs.  These likely will keep popping up but now should be set to NOT MON since commissiones have written these into GRD over the weekend.

LHO VE
kyle.ryan@LIGO.ORG - posted 13:31, Tuesday 26 May 2015 (18627)
0900-1200 Short low temp bake of BSC6 RGA
Kyle 

Ran pump cart during this period
LHO VE
kyle.ryan@LIGO.ORG - posted 13:29, Tuesday 26 May 2015 (18626)
Made change to Y-mid ion pump controller
Kyle, Gerardo 

Pump 1 channel in "STEP" mode -> changed to 5000V "FIXED" -> Both mid station ion pumps fixed at 5000V (historically) -> May change both to 7000V fixed to be consistent with all other pumps (next maintenance day?)
H1 PSL
jason.oberling@LIGO.ORG - posted 12:23, Tuesday 26 May 2015 - last comment - 12:31, Tuesday 26 May 2015(18624)
PSL Maintenance

J. Oberling, P. King, E. Merilh

Summary

Today we went into the PSL enclosure to increase the front end (FE) diode currents and tweak the PMC and FSS alignment.  We:

  • Added ~2A of current to the 4 FE diodes and tweaked their operating temperature.  We now have 33.1 W out of the FE.
  • Tweaked the PMC alignment and now have a transmitted power of 22.9 W, a reflected power of 2.4 W, and a visibility of 89.9%.
    • We will have to go back in at a later date and adjust the PMC mode matching lenses, L02 and L03, to improve the PMC transmitted power; we ran out of time today.
  • Tweaked the FSS alignment to increase the RefCav transmission and now have a RefCav TPD reading of 1.47 V and a visibility of 72.3%.
  • Checked the DBB RPD voltage to make sure it was above 9 V so we could continue to make measurements with the DBB.  It is at 9.53 V.  We also measured the power into the DBB along the 35 W laser path as 150 mW; this is >135 mW, so all is good.

Details

FE Diodes:

We added ~2A to the 4 FE diodes to increase the FE power, which had been slowly drifting down over the last several months (threshold for diode current adjustment is 5% drop, we were at ~7%).  Both power supplies are now feeding ~51A to the FE diodes.  We then had to optimize the temperature of the diodes to maximize the FE power.  Peter took before/after screenshots of the FE diode settings and will post them as a comment to this log.  We are now reading 33.1 W out of the PSL FE.

PMC:

We then proceeded to tweak the PMC alignment.  We adjusted both pitch and yaw on mirrors M06 and M07 and were able to get 22.9 W of transmitted power, with 2.4 W of reflected power.  This is obviously not ideal (we want reflected power to be <10% of transmitted power), but all we could do within the alotted maintenance window.  We will have to go back in at a later date and adjust the 2 mode matching lenses, L02 and L03.

Looking at the PMC RPD, it has a locked reading of -0.154 V and an unlocked reading of -1.52 V, giving a PMC visibility of 89.9%.

FSS:

We tweaked the alignment of the RefCav input periscope in both pitch and yaw and improved the RefCav transmission (as read from the RefCav TPD) from 0.75 V to 1.4 V.  We then adjusted the AOM in pitch/yaw to see if we could improve the TPD reading further.  We were able to improve the TPD to ~1.47 V.

Looking at the FSS RefCav RPD, it has a locked reading of 0.072 V and an unlocked reading of 0.260 V, giving a RefCav visibility of 72.3%.

DBB:

We opened the DBB shutters along the 35W laser path to measure the voltage on the DBB RPD; this has to be between 9 V and 11 V for proper DBB operation.  We measured it at 9.53 V.  We also measured the power into the DBB along the 35W laser path at 150 mW; this is >135 mW, so all is good here.

Comments related to this report
peter.king@LIGO.ORG - 12:31, Tuesday 26 May 2015 (18625)
The initial diode currents for diodes 1/2 and 3/4 were 49.0A.  To bring the pump
light monitors back up to 100% the currents were increased to 51.3A and 51.0A
respectively.

The diode temperatures were changed too.
D1, was 18.0 degC, is now 17.0 degC
D2, was 20.0 degC, is now 17.5 degC
D3, was 20.0 degC, is now 19.0 degC
D4, was 20.0 degC, is now 19.0 degC
Images attached to this comment
H1 ISC
evan.hall@LIGO.ORG - posted 06:33, Tuesday 26 May 2015 - last comment - 22:45, Wednesday 27 May 2015(18613)
Trying to power up

Dan, Kiwamu, Evan

Summary

Tonight we worked on getting the interferometer back to its low-noise state. We are stable at 10 W, but there is some instability at higher powers.

Details

ITM steering

First, at 3 W we manually steered the ITMs to a good recycling gain (38 W/W), and then updated the TMS QPD offsets. We also locked the arms in green, adjusted the green QPD offsets for maximum buildup, and then updated the ITM camera references. Then we re-enabled the ITM loops in the guardian. This allowed us to power up all the way to 21 W without significant degredation of the recycling gain.

After that, we were able to consistently engage the ASC with the guardian.

Power-up issues

However, we found that at 21 W the interferomter suddenly unlocks in a matter of minutes. There seems to be no instability in the arm or sideband buildups before the lockloss. We looked at OMC DCPD signals for signs of PI, but we did not see anything ringing up during any of our short high-power locks. Some times to look at are 02:29:50, 02:59:50, 04:57:30, 06:55:00, all 2015-05-26 UTC. But any of the other 21 W locklosses in the past 12 hours follow this pattern.

We measured the OLTFs of PRCL, MICH, SRCL, and DARM before and after powering up, but they all look fine and did not change with power. For CARM, we start at 3 W with a UGF of 14 kHz with 47° of phase. Then during power-up, the electronic gain is automatically adjusted to compensate for the increased optical gain. The algorithm for this was shooting a little high, so after power-up the UGF was more like 27 kHz with 30° of phase. This is probably fine, but we adjusted the algorithm anyway, so that the UGF is placed at 19 kHz, with 45° of phase. Anyway, this did not solve the lockloss issue.

We also tried locking at some lower powers. At 15 W the interferometer lasted for about 15 minutes before unlocking. At 10 W, the lock time seems to be indefinite (at least 90 minutes).

DARM crossover

Using FM9 in ETMY L1 LOCK L (zero at 2 Hz, pole at 5 Hz), we were able to push the L1 crossover from <1 Hz to 1.7 Hz by adjusting the filter gain from 0.16 to 0.31. Measurement attached, showing before and after. This is not included in the guardian. By pushing up the crossover, the rms drive to L2 decreases from >10000 ct to about 6000 ct or so.

Other

For the record, we did not notice any kicks to the yaw of IMC REFL tonight.

Non-image files attached to this report
Comments related to this report
daniel.hoak@LIGO.ORG - 08:02, Tuesday 26 May 2015 (18614)

New Damping Settings for Bounce, Roll, Violin modes

Over the weekend we were able to re-commission the damping of the bounce, roll and violin modes.  The bounce & violin damping settings have been propagated to the ISC_LOCK guardian, and should be stable (maybe).  The roll mode settings have already changed once over the weekend, so I'll list what's been working, but your mileage may vary.

The attached spectrum (for 10W, low-noise ESD, *not calibrated*, no LSC FF, so don't study it too closely) shows the mode-damping progress.  Note this was before the 2.4k and 2.8k violin harmonics were damped.

 

Bounce modes:

After struggling to apply very narrow band-pass filters a la Jeff's approach from alog:18483, we reverted to the method of very broad band-passes.  These are loaded as FM3 in the DARM_DAMP_V filter banks.  The frequencies follow those listed by Sheila in alog:18440 (we confirmed these frequencies were correct through the course of our damping exercise).

  ETMY ETMX ITMY ITMX
Frequency [Hz] 9.73 9.77 9.81 9.85
Filters FM1 (+60deg), FM3 FM3 FM1 (+60deg), FM3, FM6 (+30deg) FM2 (-60deg), FM3
Gain -0.3 -0.5 +1.0 +0.3

The real key to squashing the bounce mode peak was to work out the damping settings for ETMX and ITMY (the optics which couple bounce --> longitudinal motion the least).  The extra 30deg of phase for ITMY turned out to be important.

 

Roll modes:

We were able to damp the ITMX roll mode, thus breaking the unpaired set of frequencies for roll modes and assigning each peak to an optic.  The ITMX roll mode wasn't rung up this weekend, so we didn't have a chance to work out damping settings.  The sign for damping the ETMY roll mode flipped between Sunday and Monday night, otherwise these damping settings were pretty stable.

For all the TMs the FM4 filter is a broad band-pass from 13.5 to 14.5Hz.

  ETMY ETMX ITMY ITMX
Frequency [Hz] 13.816 13.889 13.930 13.978
Filters FM3 (-100dB), FM4, FM6 (+30deg) FM3 (-100dB), FM4 FM3 (-100dB), FM4 ??
Gain -20 +600 -80 ??

The roll mode is rung up after every lockloss (usually it's ETMY), so these settings need to be manually applied before the transition to DC readout.  The gains listed in the table above are the "high-gain" damping state, if the mode is very rung up you need to start at a lower gain setting or you might saturate the M0 stage.

 

Violin Modes

Recall that violin mode frequencies and their associated test masses were given in alogs 17365, 17502, and 17610.

All the identified modes are well-damped and have been enabled in the Guardian code, with the exception of ITMX.  Despite many attempts I haven't been able to actuate on the ITMX modes at all.  Before the realignment/recycling gain work the ITMX modes damped very easily, now I can't find a DOF (longitude, pitch, or yaw) or a phase setting to move the modes either up or down.  It's hard to believe the L2 stage of ITMX isn't working, so we're not sure what the problem is.  Maybe we just need more patience.

The complete set of violin mode damping settings is too large to list here; the various filters and gains are recorded in the guardian code.  Some modes require a specific filter to get the right phase, others can be grouped together with broad band-pass filters without much trouble.  In particular, ITMY requires separate filters for each mode, it's very difficult to construct a broad band-pass that catches more than one mode with the correct phase.  We need to add more filter banks to the L2 DAMP section of the quad models if we want to squash the violin modes and their harmonics.

We did identify some new modes -- since we started feeding DARM back to the ETMY L2 stage we rang up the 4th, 5th, and 6th harmonics of that optic.  These modes were easily damped and have been notched in the actuation path. The specific frequencies and damping settings were:

2424.38, 2427.25 Hz: Use FM6 of ETMY L2 DAMP MODE1, +60deg of phase, +100dB, gain=+20k, longitudinal direction

2878.7, 2882.5 Hz: Use FM6 of MODE2, no phase, gain=+10k, longitudinal direction

3330.6 Hz: Use FM5 of MODE3, -60deg of phase, gain=+20k, longitudinal direction

3335.7 Hz: Use FM6 of MODE3, no phase, gain=+20k, longitudinal direction

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sheila.dwyer@LIGO.ORG - 22:59, Tuesday 26 May 2015 (18630)

Keita, Sheila

In three of last night's 10 Watt locklosses, as well at the 15 Watt lockloss, the CARM loop dropped first, when IMC-F reached something around +/- 1440 kHz (the first screen shot attached is typical, 2015-05-26 15:23:17, 13:228:28, 12:10:29, and 7:38:16 at 15 Watts).  Now that Jeff has fixed the model and we are using tidal again, this type of lockloss has not been bothering us tonight. 

The slope of IMC-F is larger in the 15 Watt lockloss than the 10 Watts ones.  A trend of IMC F and arm transmission from last night shows there are some inflection points in the slope of IMC F, although these don't corespond to changes in input power or changes in the state of the tidal state machine.

The other 4 locklosses that I looked at were not due to the IMC VCO, and I didn't come up with any good explanation for them.  One notable feature in all of the others is the half a hertx oscillation in the ITM oplev damping loops, that starts when the power increased to 21 Watts, but it doesn't seem like this was the cause of the lockloss. 

Images attached to this comment
sheila.dwyer@LIGO.ORG - 22:45, Wednesday 27 May 2015 (18657)

Tonight we were able to damp the roll modes with all of these settings, as well as ITMX for which we used -100 dB, bp13.9 (FM3+FM4) and a gain of 20.  We also increased the gain for ETMX to 1000

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