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  16920   Wed Jun 15 17:03:17 2022 yutaUpdateSUSITMY ULCOIL issue solved, loose connection in sat amp box

[Anchal, Yuta]

We fixed the issue of ITMY ULCOIL not driving ITMY by replacing one of the 64pin ribbon cable in the satellite amplifier box.
We thought the coil driver and the sat amp box are OK by checking the voltage change at the output of the sat amp box by giving an offset to UL coil driver, but it was not giving a current change, probably due to too much contact resistance in the cables.
It was sneaky because it was not completely disconnected.

All the coils for our suspensions are now working!

What we did:
 - Using breakout boards, the output current of sat amp box was measured using FLUKE multimeter. It turned out that UL is not giving measurable current. We also confirmed that UR coil driver can drive UL by re-directing the current from UR coil driver to UL. This means that the UL magnet was not de-magnetized!
 - Measured the coil resistance from at the coil driver output and found that UL coil seen from there has too high resistance which cannot be measured with the multimeter, whereas UR coil was measured to be ~30 Ohms.
 - Went back to the feedthru and measured the resistance of UL coil. Upto the output of the Satellite Amp Terimator, the resistance was measured to be ~16 Ohms, but not at the input of the Satellite Amp Terimator (Attachment #1,2).
 - It turned out that #16 pin of 64pin ribbon cable in between the Satellite Amp Terimator (LIGO-D990021) and the Satellite Amp board (LIGO-D961289) at the Satellite Amp Terimator side was not good (Attachment #3).
 - Replaced the cable and confirmed that ULCOIL can kick ITMY (Attachment #4).
 - C1:SUS-ITMY_TO_COIL matrix was reverted to default values.

Next:
 - We might have to re-commission Yarm ASS again since pitch-yaw coupling have changed. -> EDIT: Checked that it works (except for ITM PIT L), including offloading offsets (writeASS_offsets.py), 18:30 local.
 - Now that LO1 LLCOIL issue is solved and LO2 stuck is solved, we should do the free swing test again to identify the resonant frequencies.
 - OSEM sensor diagonalization (input matrix), coil balancing (and F2A)

  16919   Wed Jun 15 15:45:37 2022 yutaUpdateSUSLO1 LLCOIL now working, it was loose connection

We tracked the issue of LO1 LLCOIL not actuating LO1, and found that the DB9 cable from the coil driver to the sat amp was loose.
I tightened the screws and now it is working.
Never ever connect cables without screwing the connectors tightly! angryno

What I did:
 - Measured the resistance and the inductance of each coil with BK PRECISION LCR meter, as I did for ITMY (Attachment #1, 40m/16896). The result is the following and it shows that LLCOIL is there.

Feedthru connector: LO1 1
Pin 3-15 / R = 16.0Ω / L = 3.27 mH (UL)
Pin 7-19 / R = 15.8Ω / L = 3.27 mH (UR)
Pin11-23 / R = 15.7Ω / L = 3.27 mH (LL)

Feedthru connector: LO1 2
Pin 3-15 / N/A
Pin 7-19 / R = 15.6Ω / L = 3.22 mH (SD)
Pin11-23 / R = 15.9Ω / L = 3.30 mH (LR)

 - Swapped the DB25 cable which goes to the feedthru LO1 1 and feedthru LO1 2. LLCOIL could be drived from LR coil driver and LRCOIL could not be drived from LL coil driver. SD and UR worked fine with the swap. This means that there is something wrong with the LL driving.
 - Went to see the rack which have coil drivers and sat amp for LO1, and immediately found that the DB9 cable was loose (Attachment #2). Tightened them and the issue was fixed.
 - C1:SUS-LO1_TO_COIL matrix gains were reverted to default values (Attachment #3).

  16918   Wed Jun 15 15:07:07 2022 KojiUpdateSUSLO2 SUS stuck fixed

I checked the state of the LO2 suspension. I found that the coil driver Enable Mon was all red. Meaning, the actuation signals were not delivered to the coil driver. I wasn't sure if this was intentional or not.

Enabled the coils with "WD Master" Shutdown -> Normal.

Immediately I saw the OSEMS flipped the sign because there was an (non-intentional) alignment offset in pitch. I've adjusted the pitch offset so that all the OSEM PDs have the voltages 4~5V.

That's it.

  16917   Wed Jun 15 15:03:41 2022 KojiUpdatePSLPMC input beam aligned

The commissioners complained about the PMC alignment. The PMC input beam was aligned. It made the transmission improved from 0.72 to 0.74.

FYI: Which steering mirrors do we use for the PMC beam alignment?
The mounts are indicated with the red arrows in Attachment 2.
You have to move these two in common and differential for each pitch and yaw.
The first steering (the right one in the picture) has the beam going through the immediate back of the mount.
So touching the yaw knob of this mount needs some care so that you don't block the PMC refl beam.

  16916   Wed Jun 15 07:26:35 2022 JCUpdateVACBeginning Pumpdown

[Jordan, JC]

Jordan and I went in to retore the Vacuum System back to it's original state before the power loss on June 8, 2022. The process went smoothly as we first closed V7 and opened VM3 (in that order).

The RP1/3 line did not have the KF blank installed. That was added and the RP flex line was capped off.

Quote:

[JC, Jordan, Paco, Chub]

We began with the pumpdown this morning. We started with the annulus volume and proceeded by using the following:

1. Isolate the RGA Volume by closing of valves VM3 and V7.

2. Opened valves VASE, VASV, VABSSCT, VABS, VABSSCO, VAEV, and VAEE, in that order.

3. Open VA6 to allow P3, FRG3, and PAN to equalize.

4. Turn on RP1 and RP3, rough out annulus volume, once <1 torr turn on TP3. Close V6. Open V5 to pump the annulus volume with TP3.

5. Re route pumping from RP1 and RP3 to the main volume by opening V3 and slowly opening RV1.

6. After ~3.5 hours the pressure in the arms was <500mtorr on both FRG1 and P1a. Turn on TP1 and wait to reach full speed 560 Hz

7. Open V1 with RV2 barely open. The pressure diff between P1a and P2/FRG2 needs to be below 1 torr. This took a couple attempts with the manual valve in different positions. The interlocks were tripped for this reason. Repeat step 7 until the manual gate valve was in a position that throttled pumping enough to maintain the <1 torr differential.

8. Slowly open the manual gate valve over the course of ~ 1 hour. Once the manual gate valve fully opened, pressure in the arms was <1mtorr.

9. V7 was closed, leaving only TP2 to back TP1, while TP3 was used to continue pumping the annuli. Left in that configuration overnight (see attached)

 

We did have to replace gauge PAN becuase it was reading a signal error. In addition, we found the cable is a bit sketchy and has a sharp bend. The signal comes in and out when the cable is fiddled with.

 

  16915   Tue Jun 14 20:57:15 2022 AnchalUpdateASCYarm ASS working now

I finally got YARM AS to work today. It is hard to describe what worked, I did a lot of monkey business and some dirty offset measurements to create the ASS output matrix that gave results. Note that I still had to leave out ITMY PIT L error signal, but transmission was maximizing without it. The beam does not center fully on ITMY in Pit direction right now, but we'll mvoe on from this problem for now. Future people are welcome to try to make it work for this last remaining error signal as well.

commit

 

  16914   Tue Jun 14 19:34:06 2022 yutaUpdateSUSResonant frequency identification from the free swing test

[JC, Anchal, Yuta]

We are working on resonant frequency idendification from the free swing test done last weekend.
Table below is the resonant frequencies identified, and attached are the plots of peak identification for some of our new suspensions.
To identify the resonant frequencies, the kicks were done in each degrees of freedom so that we can assume, for example, SUSPOS will be mostly excited when kicked in POS and the heighest peak is at the POS resonant frequency.
For PR3, AS1 and ETMY, the resonant frequency idendification needs to be done in the order of POS, PIT, YAW, SIDE and identified frequencies need to be removed when finding a peak.
Other than that, the identification was done without any prior assumptions on the suspensions.
For ITMY, ETMY, PR2, PR3, AS1, AS4, yaw has lower resonant frequencies than pitch, as opposed to other suspensions.
For LO1, POS and PIT frequencies might be swapped because LLCOIL is not working (40m/16898) and POS/PIT kicks both might be excited SUSPOS/PIT.
LO1 coil output matrix was temporarily modified so that we use only two coils for POS/PIT/YAW excitation (Attachment #7), as we did for ITMY (40m/16899).

The scripts for the free swinging test and analysis live in /Git/40m/scripts/SUS/InMatCalc

     POS    PIT    YAW    SIDE
BS   0.990  0.748  0.794  0.959 
ITMY 0.987  0.739  0.634  0.948 fPIT > fYAW
ETMY 0.979  0.816  0.649  0.954 fPIT > fYAW
ITMX 0.978  0.586  0.758  0.959 
ETMX 0.962  0.725  0.847  1.000 
PRM  0.939  0.541  0.742  0.990 
PR3  1.019  0.885  0.751  0.989 fPIT > fYAW
PR2  0.996  0.816  0.724  0.999 fPIT > fYAW
SRM  0.969  0.533  0.815  0.985 
SR2  0.978  0.720  0.776  0.997 
LO1  0.926  1.011  0.669  0.993 POS AND PIT MIGHT BE SWAPPED
LO2  0.964  0.998  0.995  0.990 WRONG DUE TO STUCK (40m/16913)
AS1  1.028  0.832  0.668  0.988 fPIT > fYAW
AS4  1.015  0.800  0.659  0.991 fPIT > fYAW
MC1  0.967  0.678  0.797  0.995 
MC2  0.968  0.748  0.815  0.990 
MC3  0.978  0.770  0.841  0.969 
  16913   Tue Jun 14 18:45:43 2022 AnchalUpdateSUSLO2 lower magnets are stuck in coil, won't come off

[Anchal, Yuta]

In the weekend, I ran a free swing test on all optics. During this test, LO2 magnets got stuck to the coil because LO2 PIT alignment was very high, making its lower OSEMs almost fully dark and upper OSEMs almost fully bright. Today we realized that LO2 is actually stuck and is not coming off even when we dither PIT alignment. We tried several ways but could not get this off. sad

Do we have any other method to get magnets off in vaccum?

It will be pretty bad if we try anything related to BHD with LO beam reflecting off a stuck mirror. Does anyone have any suggestions other than venting and fixing the issue?

  16912   Tue Jun 14 08:41:36 2022 JCUpdateOPLEV TablesBS Oplev Table Sketch

[JC]

Lately, I have been working on a 3d sketch of the BS OPLEV Table on SolidWorks. This is my progress so far, a few of the components I will have to sketch myself, such as the HeNe laser and photodiodes. This will just be a general layout of the HeNe laser, optics, and photodiodes.

  16911   Mon Jun 13 20:26:09 2022 yutaUpdateASCYarm ASS re-tuning in progress -part 2-

[Anchal, Yuta]

We are still in the progress of re-commissioning Yarm ASS.
Today, we tried to adjust output matrix by measuring the sensing matrix at DC.
Turning on yaw loops kind of works, but pitch does not. It seems like there is too much coupling in pitch to yaw.
We might need to adjust the coil output matrix of ITMY and ETMY to go further, and/or try measuring the sensing matrix including pitch - yaw coupling.

What we did:
 - Confirmed that turning on TT1 and TT2 loops (max-transmission loops) work fine. When we intentionally misalign TT1/2, the ASS loops correct it. So, we moved on to measure the sensing matrix of A2L paths, instead of using theoretical matrix caluclated from cavity geometry we used last week (40m/16909).
 - Instead of +/-1's, we put +/-2's in the ITMY coil output matrix to balance the actuation between ETMY and ITMY to take into account that ITMY is now using only two coils for actuating pitch and yaw (40m/16899).
 - Measured the change in C1:ASS-YARM_(E|I)TM_(PIT|YAW)_L_DEMOD_I_OUT16 error signals when offset was added to C1:SUS-(E|I)TMY_ASC(PIT|YAW)_OFFSET. We assumed pitch-yaw coupling is small enough here. Below was the result.

                            ETM PIT error  ITM PIT error
ETM PIT OFFSET of +100cnts: -3.0cnts       -2.99cnts
ITM PIT OFFSET of +100cnts
: -11.94cnts      -5.38cnts

                            ETM PIT error  ITM PIT error
ETM YAW OFFSET of +100cnts:
-3.42cnts      -16.93cnts
ITM YAW OFFSET of +10 cnts: +1.41cnts      +0.543cnts


 - Inverted the matrix to get A2L part of C1:ASS-YARM_OUT_MTRX. Attachment #1 is the current configuration so far.
 - With this, we could close all yaw loops when pitch loops were not on. But vise versa didn't work.
 - Anyway, we aligned the IFO by centering the beams on test masses by our eyes and centered all the oplevs (Attachment #2).

Next:
 - Do coil balancing to reduce pitch-yaw coupling
 - Measure sensing matrix also for pitch-yaw coupling
 - Xarm ASS is also not working now. We need to do similar steps also for Xarm

  16910   Fri Jun 10 21:10:01 2022 yutaUpdateSUSITMY ULCOIL mystery: Coil driver swap test

We checked the photos we have, but we didn't have the photos which show ULCOIL situation clearly.

Free swing of ITMY (and others) will be done this weekend to see the OSEM spectra and resonant frequencies.

  16909   Fri Jun 10 20:11:46 2022 yutaUpdateASCYarm ASS re-tuning in progress

[Anchal, Yuta]

We tried to re-tune Yarm ASS today. It cannot be fully closed as of now. I think we need to play with signs.

Motivation:
 - We want to make sure Yarm ASS work with current ITMY coil matrix (40m/16899).
 - ASS makes the beam positions on test masses to be the same every day.

What we did:
 - Adjusted A2L paths of C1:ASS-YARM_OUT_MTRX based on cavity geometry. For the paths to maximize the transmission using TT1 and TT2, we just assumed they are correctly calculated by someone in the past.
 - Adjusted OSC_CLKGAINs so that ITMY and ETMY will be shaken in the same amplitude in terms of radians. The ratio of the excitation was determined to take into account for the oscillator frequency difference between DOFs.
 - Checked the time constant of A2L paths by turning on A2L paths only, and checked that of max-transmission paths by turining on them only.
 - Adjusted DEMOD_SIG_GAINs so that their time constants will be roughly the same, with C1:ASS-YARM_SEN_MTRX fully identity matrix and all servo GAINs to be +1.
 - Re-tuned DEMOD_PHASEs to minimize Q signal. C1:ASS-YARM_ITM_PIT_L_DEMOD_PHASE and C1:ASS-YARM_ITM_YAW_T_DEMOD_PHASE were re-tuned within +/- 5 deg.
 - These changes are recorded in /opt/rtcds/caltech/c1/Git/40m/scripts/ASS/ASS_DITHER_ON.snap now.

Result:
 - A2L loops seems to be working, but max-transmission paths seems to diverge at some point. I think we need to play with the signs/gains of max-transmission paths for C1:ASS-YARM_OUT_MTRX.
 - Attached is the current configuration we achieved so far.

  16908   Fri Jun 10 15:04:23 2022 ranaUpdateSUSITMY ULCOIL mystery: Coil driver swap test

Its good that the inductance test passed. This means that the coil is OK. How does the inspection photo look? This is the one you guys took of the ITM OSEM that shows the position of the magnet w.r.t. the coil. Also, how does the free swinging spectra look? Either one of these might indicate a broken magnet, or a sticky EQ stop.

  16907   Fri Jun 10 15:02:04 2022 yutaUpdateSUSServo gain sign flipped for MC1 WFS relief

The servo gain for MC1 in /opt/rtcds/caltech/c1/Git/40m/scripts/MC/WFS/reliefWFS was flipped to account for COIL_GAIN flip done in 40m/16898.
The reliefWFS script now works fine.

ezcaservo -r 'C1:SUS-MC2_ASCPIT_OUT16' -g ${g} -t ${ts} C1:SUS-MC2_PIT_COMM & 
ezcaservo -r 'C1:SUS-MC2_ASCYAW_OUT16' -g ${g} -t ${ts} C1:SUS-MC2_YAW_COMM & 
ezcaservo -r 'C1:SUS-MC1_ASCPIT_OUT16' -g -${g} -t ${ts} C1:SUS-MC1_PIT_COMM &  
ezcaservo -r 'C1:SUS-MC1_ASCYAW_OUT16' -g -${g} -t ${ts} C1:SUS-MC1_YAW_COMM & 
ezcaservo -r 'C1:SUS-MC3_ASCPIT_OUT16' -g ${g} -t ${ts} C1:SUS-MC3_PIT_COMM & 
ezcaservo -r 'C1:SUS-MC3_ASCYAW_OUT16' -g ${g} -t ${ts} C1:SUS-MC3_YAW_COMM & 
 

  16906   Fri Jun 10 13:52:22 2022 JCUpdateOPLEV TablesITMX, ITMY, and Vertex Table Beam Paths

I have at taken photos and added arrows which signify the beam paths for ITMX, ITMY, and Vertex Oplev tables.

  16905   Fri Jun 10 13:02:14 2022 yutaUpdateSUSITMY ULCOIL mystery: Coil driver swap test

ITMY ULCOIL was measured to have ~3.3 mH as measured from the flange. RTFE 40m/16896 .
 

Quote:

what was the result of the inductance measurement? should be ~3.3 mH as measured from the flannge or cable that goes to the flange from sat amp.

 

 

  16904   Thu Jun 9 23:08:39 2022 ranaUpdateSUSITMY ULCOIL mystery: Coil driver swap test

what was the result of the inductance measurement? should be ~3.3 mH as measured from the flannge or cable that goes to the flange from sat amp.

 

  16903   Wed Jun 8 18:16:20 2022 yutaUpdateSUSITMY ULCOIL mystery: Coil driver swap test

To see if the ULCOIL channel of the ITMY coil driver is working or not, I swapped ITMY coil driver and ITMX coil driver by swapping DB15 cable (see Attachment #2).

With this swap, I confirmed that ITMX can be kicked with C1:SUS-ITMY_ULCOIL_OFFSET, but ITMY cannot be kicked with C1:SUS-ITMX_ULCOIL_OFFSET (see Attachment #1).

This means that the issue is not the in-air electronics.
Mystery remains again...
We need to investigate ITMY ULCOIL in the next vent.


I revereted the swap and confirmed that damping loops work fine again.

  16902   Wed Jun 8 16:57:46 2022 KojiUpdateIOOPower Outage 220608: IMC restored

The IMC alignment was restored and the IMC is nicely locking.

Once the vacuum level recovered P<1e-4 torr, the PSL shutter was able to be opened.

The IMC was still flashing, so the lock to TEM00 was possible.

Once it was locked, the MC2 alignment was tweaked and the autolocker and the WFS kicked in to help the locking/alignment.

The transmission is ~13k and seems reasonable considering the low PMC transmission of the PMC (0.672)

  16901   Wed Jun 8 16:33:26 2022 KojiUpdateGeneralPower Outage 220608: HVAC restored

I found the HVACs for the ends were off. They were turned back on.

  16900   Wed Jun 8 16:03:12 2022 KojiUpdateVACPower Outage 220608: Vacuum Recovery

=== Observation ===

  • TP1/2/3 failed. AUX RP did not survive the power outage (of course)

=== Initial Recovery of TP2/TP3 ===

  • Stopped TP1/2/3
  • Restored RP AUX at the wall breaker module
  • Restarted TP2/3

=== Rough pumping down ===

  • Found RP1/RP3 left connected (unusual)
  • Turned on RP1 and RP3
  • Opened V6 and V7 for roughing of the pump spool. Now 0.3 torr for P2/P3/PA* (annuli) - ready to open V4 and V5 to backup TP1 by TP2 and TP3. Waiting for TP2/3 to be accelerated

=== Towards main volume pumping ===

  • TP2 accelerated and opened V4 (This caused V6 to close). RP1 and RP3 stopped.
  • TP3 hasitated to spin up. Stopped for now.
  • TP1 needed to be reset to clear the displacement errors. Once the errors were cleared, TP1 was restarted (acclerating).
  • TP1 at normal speed. Opened V1 (main volume pumping started)
     
  • Disconnected RP1/RP3 line.
     
  • TP3 was restarted and is now stable at 55k RPM (indicated as soft spin / low speed). Pushed "Stand By On" and "then "Stand By OFF". This makes the TP3 back to "NORMAL". Switched to "Stand By On".
  • TP2 was also switched to "Stand By On".

Now the main volume and the annuli are pumped down TP1 and TP2/TP3 with RP AUX backing.

The attachment is the pressure glitch for the main volume.

 

  16899   Tue Jun 7 19:40:45 2022 AnchalUpdateSUSITMY changed output matrix to disable use of UL coil

Since UL coil actuation is lost, we modified the output matrix of ITMY to use only UR, LR and LL face coils for POS, PIT and YAW actuation. The output matrix was changed to following:

  POS PIT YAW SIDE
UL 0 0 0 0
UR 1 1 0 0
LL 1 0 1 0
LR 0 -1 -1 0
SIDE 0 0 0 1

 

 

 

 

 

After this change, the damping was still working as good as before. I took PIT to POS/PIT/YAW and YAW to POS/PIT/YAW coupling measurements by exciting C1:SUS-ITMY_ASCPIT[YAW]_EXC and seeing effect at C1:SUS-ITMY_SUS[POS/PIT/YAW]_IN1 when the damping loops were off. Attached are the results. We were able to reduce PIT to YAW and YAW to PIT coupling by 10 dB by this simple change in output matrix. More coil balancing or off-diagonal termsmight help more and should be attempted if required. The coupling to POS did not change much.

Note that attachment 1 shows transfer functions from excitation point to the DOF sensing inputs while attachment two looks at ratio of C1:SUS-ITMY_SUS[POS/PIT]_IN1 to C1:SUS-ITMY_SUSYAW_IN1 which is the actual quantity of interest. I didn't repeat the PIT measurement due to lack of time.

Also note that all such measurements are being recorded in our new measurements git repo. We'll populate this repo with diaggui template+data files as we do measurements.

  16898   Tue Jun 7 19:13:12 2022 yutaUpdateSUSAgreement on suspension damping loop polarity conventions

Anchal, Paco and I agreed to follow the polarity conventions below for suspension damping loops.
Some of the polarity/gains were changed to homogenize all the suspensions to the convention.
All the suspensions are homogenized except for MC1 (which have all - in sensor inputs and all - in coil outputs) and AS1 (SDCOIL_GAIN have the same sign as LL).


*SEN_GAIN to be +1
INMATRIX to be the following, and calibrated so that SUSPOS/SIDE_IN will be um and SUSPIT/YAW_IN1 will be urad (calibration to be done later)
+ + + + *
+ + - - *
+ - - + *
* * * * +
SUS*_GAINS to be +

TO_COIL gains to be the following
+1 +1 +1  *
+1 +1 -1  *
+1 -1 +1  *
+1 -1 -1  *
 *  *  * +4
*COIL_GAIN to be the following or flipped one so that SUS*_GAINS will be +
+
-
+
-
+

To do this, the following changes were made

For BS, ITMX, ITMY, PRM, SRM, ETMX, ETMY, MC1, MC2 and MC3 ("old" suspensions), TO_COIL_5_4_GAIN (for side) is changed from +1 to +4 and SUSSIDE_GAINs are divided by 4 accordingly.
For ETMX, the sign of SUSSIDE_GAIN is flipped to +, and SDCOIL_GAIN to be -1 (it was +1).
For MC1, *SEN_GAINs are - (not following the convension; see 40m/16894). The sign of INMATRIX_4_5 (for side) is flipped to +, SUSPOS/PIT/YAW_GAIN are flipped to +, and *COIL_GAIN are flipped to - (not following the convension). IMC WFS output matrix components for MC1 were also flipped. 

  16897   Tue Jun 7 18:32:46 2022 DeekshaUpdateElectronicsNoise Budgeting ADC (of redpitaya)

Made plots on i/p noise of redpitaya . Need to reconsider sampling frequency (to improve plot at lower freq)
 

  16896   Tue Jun 7 17:26:21 2022 yutaUpdateSUSITMY ULCOIL mystery not solved

[Paco, Yuta]

We investigated the ITMY ULCOIL issue (40m/16873).
ULSEN is sensing the optic motion but ULCOIL cannot move the optic.
We confirmed that the coil input is there upto satellite amplifier output.
We also checked that ULCOIL have 3.3 mH and 16 Ohms, which are consistent with other coils.
Mystery remains...
We need to investigate ITMY ULCOIL in the next vent.

What we did:
 - Checked again that C1:SUS-ITMY_ULCOIL_OFFSET does not kick ITMY using OSEM sensor signals and oplev signals. ULSEN moves when ITMY is kicked by other coils.
 - Checked that kick gives voltage changes at coil driver and satellite amplifier output. We unplugged J1 DB25 cable from the feedthru flange and checked the signals sent to coil with oscilloscope.
 - Measured inductance (using BK PRECISION LCR meter) and resistance (using Fluke) of coils for ITMY. Below is the result. UL coil seems to be consistent with other coils. (It seems like BK PRECISION one wil give wrong resistance if the dial is set to the resistance value which is too low compared with the one you want to measure. If you want to measure 16Ω, set the dial to larger than 20Ω, not 2Ω)

Feedthru connector: ITMY1
Pin 3-15 / R = 16.3Ω / L = 3.32 mH (UL)
Pin 7-19 / R = 16.4Ω / L = 3.30 mH (UR)
Pin11-23 / R = 16.2Ω / L = 3.31 mH (LL)

Feedthru connector: ITMY2
Pin 3-15 / N/A
Pin 7-19 / R = 16.3Ω / L = 3.30 mH (SD)
Pin11-23 / R = 16.4Ω / L = 3.33 mH (LR)


Discussions:
 - UL is the only short OSEM in ITMY OSEMs.
 - ITMY have dumbells for magnets.
 - If UL magnet is off, ULSEN would not work. Something not magnetic is working for shadow sensing for UL? Dumbells?
 - ULSEN just sensing some coupling from other OSEMs?

  16895   Mon Jun 6 22:08:55 2022 KojiUpdateIMCMC1 OSEM sensor sign flipped, MC1/2/3 free swinging overnight for inmat diagonalization

Note that MC1 has a new style sat amp because the old one collapsed. The sign flip might have been the result of the replacement

 

  16894   Mon Jun 6 21:01:22 2022 yutaUpdateIMCMC1 OSEM sensor sign flipped, MC1/2/3 free swinging overnight for inmat diagonalization

[Tomislav Andric, Rana, Yuta]

We put -1 to MC1 OSEM sensor gains and re-tuned MC1 damping.
We also kicked MC1, MC2, MC3 tonight for input matrix diagonalization.

MC1 damping investigations:
 We put -1 to MC1 OSEM sensor gains so that UL/UR/LR/LL/SDSEN_OUT will be positive like other optics.
 OSEM damping filter gains were adjusted.
 We have also checked if having +1 for all UL/UR/LR/LL/SDCOIL_GAIN is correct or not. It has been like this at least for the past year.
 It should be -1 for UR and LL to account for magnets, but if we did put -1 or them, kick in C1:SUS-MC1_PIT_OFFSET mostly gave yaw kick and kick in C1:SUS-MC1_YAW_OFFSET mostly give pitch kick.
 So, we reverted them to be +1.

Input matrix diagonalization:
 We also kicked MC1, MC2, MC3 tonight input matrix diagonalization.
 Kick was done manually at the following times local.
  - MC1 20:08 June 6th, 2022
  - MC2 20:24 June 6th, 2022
  - MC3 20:21 June 6th, 2022
 We will leave watchdogs shutdown to free swing overnight (damping loops are "on").
 This will help get better angular sensor from OSEMs to calibrate WFS signals.

Next:
 - Investigate why MC1 coils gains have +1 for all
 - Calculate input matrix. Make sure SUSPOS/PIT/YAW/SIDE_IN will be in the units of um or urad.

Suggestions:
 - Add filter ramp time of 1sec for all by default
 - Make null stream channel from input matrix for diagnostics

  16893   Mon Jun 6 16:09:23 2022 ranaConfigurationDetCharSummary Pages: seis BLRMS

I updated the config file c1pem.ini in /users/public_html/detcharsummary/ConfigFiles, and commited it so I hope it works, but I did not have git push permissions. Does anyone know what is the idea here? Should we do our own personal git clone and modify that way or shoudl we do it with the control account.

Wiki needs to clear out all the outdated information on this workflow.

The changes are to make the y-scales useful. Currently, all of the past seis BLRMS plots are not so useful because the scales have not been set based on the actual signal levels. Let's see if this works, and we  can re-evaluate after a few weeks.

  16892   Mon Jun 6 13:35:11 2022 PacoUpdateLSCFirst calibrated spectra of MICH at AS55 Q

[Paco, Yuta]

On the topic of high AS55_Q RFPD offset, it seems it stems from a small residual offset on top of the 42 dB whitening filter gain (previously 3 dB). We verified this by looking in the past using dtt and seeing an offset of ~ 100 counts, which are consistent with the hotfix. We reverted the whitening filter gain to +24 dB, in order to accomodate the 10% power difference from AS2. We decided to move forward, and try locking MICH using AS55_Q_ERR. The IQ mixing angle was changed to -167 deg from -122 deg to minimize the signal in AS55_I_ERR. We have also added comb60 filters for AS55. The LSC_MICH filter gain was adjusted to -6 (used to be -13 in the configuration script) to get a MICH_OLTF UGF of 90 Hz (which is the previously measured value as of 2021 July), see Attachment #1 for the MICH OLTF estimate.

We then calibrate MICH using the fringe amplitude, so that  4 \pi I_{0} / \lambda = 1.299 \times 10^9 {\rm cts / m}, where I_{0} is the amplitude of the error point (C1:LSC-AS55_Q_ERR_DQ) in our case ~ 110 +- 2 counts. The calibrated error point spectral density is shown in Attachment #2. Calibration is done into meters in terms of difference between BS to ITMX length and BS to ITMY length.

  16891   Mon Jun 6 09:37:16 2022 JCUpdateSUSInMatCalc

[Paco, JC]

Paco and I attempted to calculate the input matrices from May 24, 2022, but the OSEM data was all saturated and not very useful. Therefore, we decided to manually investigate the appropriate coil offsets for all BHD SUS. Before, the default offset kick was 30000 counts, but we found that LO1, AS1, AS4, and PR2 cannot take more than 5000 counts. As for LO2, SR2, and PR3 cannot take more than 2000 counts before saturating. Note that all these kick test were taken by kicking OSEM UL on all BHD Optics.

 

We started the freeSwing.py script on tmux freeSwing session for tomorrow at 1:00 am for only the 5000 count offset SUS.

 

  16890   Sun Jun 5 19:46:40 2022 PacoUpdateLSCFixed IMC Trans sum issue

[Paco]

Fixed the issue below:

Quote:

Other Issues:
 - C1:IOO-MC_TRANS_SUM is now stuck at 14009. MC auto locker doesn't work correctly. FIX ME!

by noting that the C1:IOO-MC_TRANS_SUMFILT_OUT was being held to 14009 counts for some reason. Disabling hold quickly let the IMC autolocker act back.

WFS were also turned ON, and there were a couple other control outputs being held on that loop... Strange!

  16889   Fri Jun 3 17:42:50 2022 yutaUpdateLSCMICH locks with AS55_Q

AS path at AP table as re-aligned and confirmed that MICH can be locked with AS55 Q.

What we did:
  - Aligned AS55 and AS110 paths at AP table. AS55 was not receiving enough light. AS110 was not receiving light at all.
  - Changed AS55 I and Q whitening gain from 3dB to 42dB.
  - Zero-ed the RF offsets manually. C1:LSC-AS55_Q_IN1 is having too large offset. When PSL shutter was closed, it reads 13950! Needs investigation.
  - Locked MICH with PRM mis-aligned with configurations attached.

Other Issues:
 - C1:IOO-MC_TRANS_SUM is now stuck at 14009. MC auto locker doesn't work correctly. FIX ME!

  16888   Fri Jun 3 15:22:51 2022 yutaUpdateLSCBoth arms locked with POY/POX, IR beam centered on TMs with ASS

[JC, Paco, Yuta]

We locked both Y and X arms with POY11 and POX11.
RFM fix (40m/16887) enabled us to use triggering using C1:LSC-TRY/X_OUT.
IR beam is now centered on TMs using ASS (for Yarm, ASS loops cannot be closed fully, so did it manually).

What we did:
 - Aligned both arms so that the beams are roughly centered at TMs using cameras.
 - Yarm lock was easy, but Xarm lock required gain tuning. Somehow, Xarm required x3 higher gain as follows, although the amplitude of POX11_I_ERR seems to be almost the same as POY11_I_ERR. I suspect it is something to do with power normalization matrix (TRX flashing is almost a double of TRY flashing).

C1:LSC-YARM_GAIN = 0.01
C1:LSC-XARM_GAIN = 0.03

 - Run ASS for Yarm. ASS loops cannot be closed fully using default feedback parameters. I guess this is because ITMY ULCOIL is not working (40m/16873). ASS demodulated signals were manually zero-ed by manually aligning ETMY, ITMY and PR3 (and some TT1 and TT2), except for demodulated signals related to ITMY. Beam on ITMY was centered just by using our eyes.
 - Run ASS for Xarm. It seemed to work well.
 - After this, TRX and TRY were as follows and beam positions on TMs were as attached.

C1:LSC-TRX_OUT ~0.95
C1:LSC-TRY_OUT ~ 0.58

(TRX is somehow lower than what we had yesterday... 40m/16886; TRX and TRY photodiode alignment was checked, but seems to be OK.)

 - Centered TMs and BS oplevs.

Next:
 - POX and POY demodulation phases are not fully optimized. Needs re-tuning.
 - Tweak GRX and GRY injection (restore GRY PZTs?)
 - Install ETMXT camera (if it is easy)
 - MICH locking
 - RTS model for BHD needs to be updated

  16887   Fri Jun 3 12:13:58 2022 PacoConfigurationCDSFix RFM channels

[Paco, Yuta]

We tried fixing the issue of LSC_TRY and LSC_TRX channels not working. We first did some investigation, and just like previously reported by Chris, narrowed down the issue to the RFM channels coming from c1iscex/c1iscey.

First attempt : FAIL

In our first attempt, we

  1. Tripped ETMX/ETMY watchdogs, ssh to c1iscex/c1iscey and restart the rtcds models.
  2. Since the last step didn't fix things, we decided to do the same thing on c1lsc, c1sus, c1ioo.
  3. After hard rebooting c1ioo and c1lsc (because they died during the stopping of rtcds models), and not experiencing any timing issues (nice), we still don't fix the issue.

Second attempt: Success

A second attempt just followed Koji's previous fix explained here. Basic difference with our first attempt was a hard reboot of c1iscex/c1iscey in addition to the rtcds model restarting. RFM channels were then clear of errors and we recovered our IR transmission channels in the LSC model.

  16886   Thu Jun 2 20:05:37 2022 yutaConfigurationPSLIMC input power recovered to 1W, some alignment works

[Paco, Yuta]

We have increased the output power from the PSL table to 951 mW (it was 96.7 mW).
IMC was recovered including WFS, and both arms are flashing nicely in IR.
We tweaked the alignment of GRX and GRY injection to align them with IR, but it was hard.
Right now IR beams are not centered on TMs. We should center them first.

What we did:
Power increase and IMC recovery
 - Replaced a beam splitter which splits the beam into IMC REFL RF PD path and WFS path from R=98% to R=10% one. Reflection goes to RF PD.
 - Put a R=98% beam splitter back into WFS path.
 - We also tried to put a window in front of IMC REFL camera to recover the arrangement in 40m wiki, but the beam reflected from the window was too weak for us to align. So, we decided not to place a window in front of the camera.
 - Attached photos are the IMC REFL path before and after the work.
 - Measured the PSL output power as Koji did in elog 40m/16672. It was measured to be 96.7+/- 0.5 mW.
 - Rotated the HWP using the Universal Motion Controller (it was not possible for us to do it from the MEDM screen). The position was changed from 73.99 deg to 36.99 deg. Output power was measured to be 951 +/- 1 mW
 - IMC locked without any other changes.
 - Changed C1:IOO-WFS_TRIGGER_THRESH_ON to 5000 (was 500). IMC WFS also worked.
 - After running MC WFS relief script, WFS DC offsets and RF offsets are adjusted following the steps in elog 40m/16835. Below are the results.

C1:IOO-WFS1_SEG1_DC.AOFF => -0.0008882080010759334
C1:IOO-WFS1_SEG2_DC.AOFF => -0.0006527877490346629
C1:IOO-WFS1_SEG3_DC.AOFF => -0.0005847311617496113
C1:IOO-WFS1_SEG4_DC.AOFF => -0.0010395992663688955
C1:IOO-WFS2_SEG1_DC.AOFF => -0.0025944841559976334
C1:IOO-WFS2_SEG2_DC.AOFF => -0.003191715502180159
C1:IOO-WFS2_SEG3_DC.AOFF => -0.0036688060499727726
C1:IOO-WFS2_SEG4_DC.AOFF => -0.004011172490815322


IOO-WFS1_I1         :  +1977.7 ->    +2250 (Significant change)
IOO-WFS1_I2         :  +3785.8 ->  +3973.2
IOO-WFS1_I3         :  +2014.2 ->  +2277.7 (Significant change)
IOO-WFS1_I4         :  -208.83 ->  +430.96 (Significant change)
IOO-WFS1_Q1         :  +2379.5 ->  +1517.4 (Significant change)
IOO-WFS1_Q2         :  +2260.4 ->  +2172.6
IOO-WFS1_Q3         :  +588.86 ->  +978.98 (Significant change)
IOO-WFS1_Q4         :  +1654.8 ->  +195.38 (Significant change)
IOO-WFS2_I1         :  -1619.9 ->  -534.25 (Significant change)
IOO-WFS2_I2         :  +1610.4 ->  +1619.8
IOO-WFS2_I3         :  +1919.6 ->  +2179.8 (Significant change)
IOO-WFS2_I4         :    +1557 ->  +1426.6
IOO-WFS2_Q1         :   -62.58 ->  +345.56 (Significant change)
IOO-WFS2_Q2         :  +777.01 ->  +805.41
IOO-WFS2_Q3         :  -6183.6 ->  -5365.8 (Significant change)
IOO-WFS2_Q4         :  +4457.2 ->  +4397.


IFO Alignment
 - Aligned both arms using IR. Both arm flashes at the following, which is consistent with the power increase.
 C1:SUS-ETMX_TRX_OUT_DQ ~1.1
 C1:SUS-ETMY_TRY_OUT_DQ ~0.6
 - With this, we tried to tweak GRX and GRY injection. The following is after the work. We could increase GTRX to 0.204 when the Xarm is aligned to green. This suggests that GRX injection is not aligned nicely yet. But the beams are also not centered on TMs. We should center them first.
 C1:ALS-TRX_OUT_DQ ~0.13
 C1:ALS-TRY_OUT_DQ ~0.07
 - GTRX and GTRY cameras are adjusted to have nicer images. In GRX path, the second and last lens before the PD and CCD was pulled ~ 1 cm behind its original position and both beams realigned. Then, on GRY path, the beam was re-centered on the first and only lens, the whole assembly pushed forward by ~ 2 cm and the beams re-centered.

Next:
 - Center the IR beam on TMs (first by our eyeballs; better to use A2L after arm locking is recovered and coils are balanced)
 - Tweak GRX and GRY injection (restore GRY PZTs?)
 - Install ETMXT camera (if it is easy)
 - Lock Xarm and Yarm (C1:LSC-TRX/Y_OUT needs to be fixed for triggering. Can we use other PDs for triggering?)
 - MICH locking (REFL and AS PDs might need to be re-aligned; they are not receiving much light)
 - RTS model for BHD needs to be updated

  16885   Wed Jun 1 12:56:44 2022 PacoSummaryElectronicsSTEMlab 125 handout

[Paco, Deeksha]

Yesterday I handed Deeksha a red pitaya (stemlab 125 - 10) to begin her summer work in the lab. The short term goal (~1 week) is to get it to work as a network analyzer and perhaps characterize its ADC/DAC noise spectra.

  16884   Wed Jun 1 11:56:28 2022 yutaUpdateALSShutter driver for GRY replaced

[JC, Yuta]

We replaced a shutter driver for GRY since it stopped working this morning.
We replaced it with a free driver which was sitting on the ITMY table.
The reverse polarity issue of C1:AUX-GREEN_Y_Shutter was fixed by switching one of the switches of the driver from N.O. to N.C.

Also, "Toggle" button was added to IFO_ALIGN.adl so that we can toggle shutters easily to find TEM00. It runs /home/controls/Git/40m/scripts/ALS/ShutterToggler.py.
 

Quote:
 

The green Y shutter now works but in reverese, meaning that sending 1 to C1:AUX-GREEN_Y_Shutter closes the shutter and vice versa. This needs to be fixed.

 

  16883   Tue May 31 17:30:01 2022 YehonathanUpdateBHDGreen shutters fixed

[Paco, Yehonathan]

We fixed the slow control over the green beam shutters.

At the Y arm the wrong BNC was connected to the shutter driver. We connected the correct BNC to the driver and switched the remote mode. The green Y shutter now works but in reverese, meaning that sending 1 to C1:AUX-GREEN_Y_Shutter closes the shutter and vice versa. This needs to be fixed.

At the X end the problem was a bit more complicated. Previously, the shutter was controlled by c1auxey. We figured that c1auxex has a lot of spare bio channels. We found an Acromag BNC front panel (with wires already soldered to the BNCs) lying around in the lab and installed it on the c1auxex Acromag chassie. We then connected the topmost BNC to channel 0 on XT1111A in the chassie. The BNC was connected to the green shutter driver on the X end.

EPIC channel was added to the c1auxex db file while it was commented out on the psl shutters db file. Modbus was restarted on c1auxex and c1psl. c1psl had to be burt restored to regain MC lock. Now the green X shutter works properly.

  16882   Tue May 31 14:44:02 2022 JCUpdateElectronicsCRT TV / Monitor 6

[Paco, JC]

Paco and I fixed the ethernet cable which was hanging. We stopped models c1x07 and c1su2, realigned the cable to follow the shelf from top, and returned to turn on the computers.

 

Note: There was not a long enough ethernet cable, so we used a female to female adapter and attached 2 ethernet cables.

Quote:

[Yehonathan, Paco, Yuta, JC]

As we were cleaning up this morning, we heard a high pitch sound that turned into a buzz. After searching for where the sound came from, we noticed the CRT TV went out. We swapped this out with a moniter and used a BNC to VGA adapter to display the cameras.

 

  16881   Fri May 27 17:46:48 2022 PacoSummaryComputersCDS upgrade visit, downfall and rise of c1lsc models

[Paco, Anchal-remote, Yuta, JC]

Sometime around noon today, right after cds upgrade planning tour, c1lsc FE fell. We though this was ok because anyways c1sus was still up, but somehow the IFO alignment was compromised (this is in fact how we first noticed this loss). Yuta couldn't see REFL on the camera, and neither on the AP table (!!) so somehow either/all of TT1, TT2, PRM got affected by this model stopping. We even tried kicking PRM slightly to try and see if the beam was nearby with no success.

We decided to restart the models. To do this we first ssh into c1lsc, c1ioo and c1sus and stop all models. During this step, c1ioo and c1sus dropped their connection and so we had to physically restart them. We then noticed DC 0x4000 error in c1x04 (c1lsc iop) and after checking the gpstimes were different by 1 second. We then did stopped the model again, and from fb1 restart all daqd_* services and modprobe -r gpstime, modprobe gpstime, restart c1lsc and start the c1x04 model. This fixed the issue, so we finished restarting all FE models and burt restore all the relevant snap files to today 02:19 AM PDT.

This made the IFO recover its nominal alignment, minus the usual drift.

* The OAF model failed to start but we left it like so for now.

  16880   Fri May 27 17:45:53 2022 yutaConfigurationBHDBHD camera installed, GRY aligned

[JC, Paco, Yuta]

After the IFO recovery (elog 40m/16881), we installed an analog camera for BHD fringe using a BNC cable for old SRMF camera so that we can see it from the control room.
We also aligned AS-LO using LO1,LO2 and AS4.
We then aligned GRY injection to get maximum GTRY.

Maximum TEM00s right now are
 C1:SUS-ETMX_TRX_OUT_DQ ~0.1
 C1:SUS-ETMY_TRY_OUT_DQ ~0.05
 C1:ALS-TRX_OUT_DQ ~0.20
 C1:ALS-TRY_OUT_DQ ~0.18

  16879   Fri May 27 15:53:17 2022 TommyUpdateElectronicsRFSoC MTS Work

With some help from the forums, we printed the status of the DAC MTS sync and were able to determined that our board's vivado design does not have MTS enabled on each tile. To fix this, we will need to construct a new Vivado desgin for the board. We were also warned to "make sure to generate correctly a PL_clock and a PL_sysref with your on board clock synthesizers and to capture them in the logic according to the requirements in PG269" of the RF Manual. From this we should be able to sync the DAC and ADC tiles as desired.

Quote:

We followed the manual's guide for setting up MTS to sync on external signal. In the xrfdc package, we update the RFdc class to have RunMTS, SysRefEnable, and SysRefDisable functions as prescribed on page 180 of the manual. Then, we attempted to run the new functions in the notebook and read the DAC signal outputs on an oscilloscope. The DACs were not synced. We were also unable to get FIFOlatency readings. 

 

  16878   Fri May 27 12:15:30 2022 JCUpdateElectronicsCRT TV / Monitor 6

[Yehonathan, Paco, Yuta, JC]

As we were cleaning up this morning, we heard a high pitch sound that turned into a buzz. After searching for where the sound came from, we noticed the CRT TV went out. We swapped this out with a moniter and used a BNC to VGA adapter to display the cameras.

  16877   Thu May 26 19:55:43 2022 yutaConfigurationBHDOplevs centered, BHD DCPDs are now online

[Paco, Yuta]

We have aligned the IFO (except for LO-AS and GRY), and centered all the oplevs.
We have also restored Gautam's in-air BHD DCPD setup and placed it to ITMY table.
BHD DC PD signals are now online at C1:XO4-MADC1_EPICS_CH4 and CH5. 

Oplevs:
 Aligned the IFO following the steps in elog 40m/16875.
 When we were woking on BHD DCPDs, we lost REFL beam on camera and both arms flashing. Alignment was restored mostly with TT2 pitch.
 We centered all the oplevs after the recovery (see attached).

BHD DCPDs:
 1. We removed a circuit box with M2 ISS photodetector readout board from AP table, in-air BHD photodiodes from optics graveyard. (see LIGO-E2000436 and elog 40m/15493 for wiring diagram)
 2. Taken out temporary two Thorlabs PDA100A used for aligning LO-AS during the vent from ITMY table, and placed the BHD setup in ITMY table (see attached and attached).
 3. DB9 cable (15ft+10ft) was connected from M2 ISS box to anti-aliasing chassis for ADC1 of C1X04 at 1Y2 rack (see attached).
 4. +/-18V power for M2 ISS box was supplied from 1Y1 rack.
 5. BHD DCPD signals are now available at C1:XO4-MADC1_EPICS_CH4 and CH5 (see attached).

Next:
 - Tweak alignment of green Y input to follow Yarm
 - Do LO-AS alignment
 - Centering of PDs everywhere with IFO aligned
 - Update RTS model for BHD

  16876   Thu May 26 15:55:10 2022 TommyUpdateElectronicsRFSoC Power Spectrum

Finished building power spectrum analyzer for the RFSoC. There are two things that I would like to address down the road. First is that there is an oscillation between positive and negative voltages at the ADC sampling frequency. This creates an undesirable frequency component at the sampling rate. I have not yet figured out the cause of this positive to negative oscillation and have simply removed half of the samples in order to recover the frequency. Therefore, I would like to figure out the root of this oscillation and remove it. Also, we have a decimation factor of 2 as default by the board which we would like to remove but have been unable to do so.

Example: 8 MHz Square Wave from SRL signal generator.

  16875   Wed May 25 17:34:47 2022 yutaConfigurationBHDIFO recovery - IFO alignment

IFO aligned to maximize flashings, except for GRY and LO-AS.

What we did:
 0. After recovering IMC, C1:IOO-MC_TRANS_SUM was ~1300 with C1:IOO-MC_RFPD_DCMON of ~0.11 (~10% better than what we had during vent). Xarm and Yarm was already flashing and could see the beam at AS and POP cameras.
 1. Aligned ETMX and ITMX to green X input beam to maximize C1:ALS-TRX_OUT, to ~0.19.
 2. Aligned TT2-PR3 to get C1:SUS-ETMX_TRX_OUT flashing at 0.09 at max
 3. Aligned ITMY to have nice POP blinking of MICH at POP camera
 4. Aligned ETMY-PR3 to have C1:SUS-ETMX_TRX_OUT flashing at 0.06 at max
 5. Misaligned ITMY (with +2 in C1:SUS-ITMY_PIT_COMM), and aligned PRM to have PRX (PRM-ITMX cavity) flashing at C1:LSC-ASDC_IN1 at ~20 (offset -70) at max
 6. Misaligned PRM, and aligned SRM to have SRX (SRM-ITMX cavity) flashing at C1:LSC-ASDC_IN1 at ~20 (offset -70) at max
 7. Restored all the alignment. ITMY didn't quite come back, so I need to tweak the alignement to maximize TRY flashing.

Result:
Current alignment is as attached. IR beam at AS, REFL, MCR and green beam at GTRX cameras all seem slightly to the left from monitors, but looks as it was before the pump down.yes GTRY is still clipped, but green Y locks stably. Oplevs were not so useful to recover the alignment. ETMX/Y oplevs did not drifted too much probably because we don't have in-vac steering mirrors.

Next:
 - Tweak alignment of green Y input to follow Yarm
 - Do LO-AS alignment
 - REFL DC is not receiving beam. Re-alignment necessary
 - Oplev centering
 - BHD PDs need to be replaced to lower gain PDs and need to be connected to CDS

  16874   Wed May 25 16:56:44 2022 PacoConfigurationBHDIFO recovery - IMC alignment

[Yuta, Paco]

We aligned IMC to recover the IFO progressively. First step was to center the MC REFL beamspot on the camera as well as the WFS DC. Then slide MC2 and MC3 together. Below are the alignment slider positions before/after.

  MC1 (before --> after) MC2 (before --> after) MC3 (before --> after)
PIT -0.3398 --> -0.4768 4.1217 --> 4.0737 -1.9808 --> -1.9308
YAW -0.8947 --> -0.7557 -1.2350 --> -1.3350 1.5598 --> 1.5638
  16873   Wed May 25 16:38:27 2022 yutaUpdateSUSSuspensions quick health check

[JC, Yuta]

We did a quick health check of suspesions after the pump down.

Summary:
 - ITMX LRSEN is too bright (~761) and not responding to any optic motions (we knew this before the pump down)
 - ITMY ULCOIL is not working
 - LO1 LLCOIL is not working
 - Damping loops need to be retuned, especially for ETMY (too much damping), SRM, PR3 and AS4 (damping too weak)
 - MC1 sensor outputs are minus instead of plus
 - LO2 OSEMs got stuck during the pump down, but now it is free after some kicks. OSEM sensorr values almost came back (see attached)

What we did:
 1. Kicked optics with C1:SUS-{optic}_{UL,LL,UR,LR,SD}COIL_OFFSET one by one with offsets of +/- 10000 (or 100000), and checked if C1:SUS-{optic}_{UL,LL,UR,LR,SD}SEN_OUT16 move in both directions.

 2. Check if the optic damps nicely.

 3. Attached photo of the note is the result.

  16872   Tue May 24 15:21:13 2022 AnchalUpdateBHDFreeswing tests of new SOS started

I modified the script freeSwing.py to use damping loop output switches to free the optic instead of watchdog or coil output filters. This ensures that the free swing test is being done at the nominal position of the optic. I started tests for LO1, LO2, As2, As4, PR2, PR3, and SR2 in a tmux session names freeSwing on rossa.


Note: LO2 face OSEMs are hardly sensitive to any motion right now due to excessive pitch offset required for LO beam. We should relieve this offset to LO1 and rerun this test later.

  16871   Tue May 24 11:04:53 2022 JCUpdateVACBeginning Pumpdown

[JC, Jordan, Paco, Chub]

We began with the pumpdown this morning. We started with the annulus volume and proceeded by using the following:

1. Isolate the RGA Volume by closing of valves VM3 and V7.

2. Opened valves VASE, VASV, VABSSCT, VABS, VABSSCO, VAEV, and VAEE, in that order.

3. Open VA6 to allow P3, FRG3, and PAN to equalize.

4. Turn on RP1 and RP3, rough out annulus volume, once <1 torr turn on TP3. Close V6. Open V5 to pump the annulus volume with TP3.

5. Re route pumping from RP1 and RP3 to the main volume by opening V3 and slowly opening RV1.

6. After ~3.5 hours the pressure in the arms was <500mtorr on both FRG1 and P1a. Turn on TP1 and wait to reach full speed 560 Hz

7. Open V1 with RV2 barely open. The pressure diff between P1a and P2/FRG2 needs to be below 1 torr. This took a couple attempts with the manual valve in different positions. The interlocks were tripped for this reason. Repeat step 7 until the manual gate valve was in a position that throttled pumping enough to maintain the <1 torr differential.

8. Slowly open the manual gate valve over the course of ~ 1 hour. Once the manual gate valve fully opened, pressure in the arms was <1mtorr.

9. V7 was closed, leaving only TP2 to back TP1, while TP3 was used to continue pumping the annuli. Left in that configuration overnight (see attached)

 

We did have to replace gauge PAN becuase it was reading a signal error. In addition, we found the cable is a bit sketchy and has a sharp bend. The signal comes in and out when the cable is fiddled with.

ELOG V3.1.3-