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ID Date Author Type Category Subjectup
  17009   Sat Jul 16 02:44:10 2022 KojiUpdateIOOIMC servo tuning

I wasn't sure how the IMC servo was optimized recently. We used to have the FSS over all gain (C1:PSL-FSS_MGAIN) of +6dB a few years back. It is not 0dB. So I decided to do a couple of measurements.

1) Default setting:

C1:IOO-MC_REFL_GAIN +4
C1:IOO-MC_BOOST2 +3
C1:IOO-MC_VCO_GAIN +13
C1:PSL-FSS_MGAIN +0
C1:PSL-FSS_FASTGAIN +19

2) Looked at the power spectrum at TEST1A output (error signal)
TEST1A is the signal right after the input gain stage (C1:IOO-MC_REFL_GAIN). Prior to the measurement, I've confirmed that the UGF is ~100Hz even at +0dB (see next section). It was not too bad even with the current default. Just wanted to check if we can increase the gain a bit more.
The input gain was fixed at +4dB and the FSS overall gain C1:PSL-FSS_MGAIN was swept from +0 to +6.
At +5dB and +6dB, the servo bump was very much visible (Attachment 1).
I decided to set the default to be +4dB (Attachment 3).

3) Took OLTF at 0dB and 4dB for the FSS overall gain.

Now the comparison of the opel loop transfer functions (OLTF) for C1:PSL-FSS_MGAIN at 0dB and 4dB. The OLTF were taken by injectiong the network analyzer signal into EXCA and measure the ratio between TEST1A and TEST1B (A/B).

C1:PSL-FSS_MGAIN +0 -> UGF 100kHz / Phase Margin ~50deg
C1:PSL-FSS_MGAIN +4 -> UGF 200kHz / Phase Margin 25~30deg

The phase margin was a bit less but it was acceptable.

4) IMC FSR

Took the opportunity to check the FSR of the IMC. Connected a cable to the RF MON of the IMC REFL demod board. Looked at the peak at 40.56MHz (29.5MHz + 11.066MHz). The peak was not so clear at 11.066195MHz (see 40m ELOG 15845). The peak was anyway minimized and the new modulation frequency was set to be 11.066081MHz (new FSR). The change is 10ppm level and it is within the range of the temp drift.

Attachment 1: ErrorPSD.pdf
ErrorPSD.pdf
Attachment 2: OLTF.pdf
OLTF.pdf
Attachment 3: Screen_Shot_2022-07-16_at_03.59.05.png
Screen_Shot_2022-07-16_at_03.59.05.png
  16143   Sat May 15 14:54:24 2021 gautamUpdateSUSIMC settings reverted

I want to work on the IFO this weekend, so I reverted the IMC suspension settings just now to what I know work (until the new settings are shown quantitatively to be superior). There isn't any instruction here on how to upload the new settings, so after my work, I will just restore from a burt-snapshot from before I changed settings.

In the process, I found something odd in the MC2 coil output filter banks. Attachment #1 shows what it it is today. This weird undetermined state of FM9 isn't great - I guess this flew under the radar because there isn't really any POS actuation on MC2. Where did the gain1 filter I installed go? Some foton filter file corruption? Eventually, we should migrate FM7,FM8-->FM9,FM10 but this isn't on my scope of things to do for today so I am just putting the gain1 filter back so as to have a clean FM9 switched on.

Quote:

The old setting can be restored by running python3 /users/anchal/20210505_IMC_Tuned_SUS_with_Gains/restoreOldConfigIMC.py from allegra or donatella.

 

I wrote the values from the c1mcs burt snapshot from ~1400 Saturday May 15, at ~1600 Sunday May 16. I believe this undoes all my changes to the IMC suspension settings.

Attachment 1: MC2coilOut.png
MC2coilOut.png
  16147   Thu May 20 10:35:57 2021 AnchalUpdateSUSIMC settings reverted

For future reference, the new settings can be upoaded from a script in the same directory. Run python /users/anchal/20210505_IMC_Tuned_SUS_with_Gains/uploadNewConfigIMC.py from allegra.

Quote:

There isn't any instruction here on how to upload the new settings

  5642   Mon Oct 10 12:14:00 2011 MirkoUpdateComputer Scripts / ProgramsIMC simulations

[Mirko, Kiwamu]

I tried to answer two questions regarding the IMC:

1. What is the coupling of fluctuations in the SB freq. to SB transmitted power?
2. What (if any) is the influence of the IMC on the AM?

I ran into some weird things regarding the corresponding optickle simulations:
1. There seems to be some artifact at the beginning of every simulation sweep.
2. The position of features depends on the parameters of the sweep.

I mailed Matt asking if he sees some error in the simulations

opticke_xaxis.png

Attachment 2: DC_power.png
DC_power.png
Attachment 3: DC_power_B.png
DC_power_B.png
Attachment 4: IMC_simulation.zip
  17001   Wed Jul 13 18:58:17 2022 KojiUpdateIOOIMC suspecion

This is just my intuition but the IMC servo seems not so optimized. I can increase the servo gain by 6~10dB easily. And I couldn't see that the PC drive went mad (red) as I increase the gain (=UGF).
The IMC needs careful OLTF measurements as well as the high freq spectrum observation.

It seems that I have worked on the IMC servo tuning in 2014 July/Aug. Checking these elogs would be helpful.

  15881   Mon Mar 8 19:22:56 2021 ranaSummarySUSIMC suspension characterization

Herewith, I describe an adventure

  1. Balance the OSEM input matrix using the free swinging data (see prev elogs).
  2. Balance the coil actuation by changing the digital coil gains. This should be done above 10 Hz using optical levers, or some IMC readout (like the WFS). At the end of this process, you should put a pringle vector into the column of the SUS output matrix that corresponds to one of the SUS OSC/LOCKIN screens. Verily, the pringle excitation should produce no signal in MC_F or da WFS.
  3. use the Malik doc on the single suspension to design feed-forward filters for the SUS COIL filter banks. You can get the physical parameters using the design documents on DCC / 40m wiki and then modify them a bit based on the eigenfrequencies in the free swinging data.
  4. Model the 2x2 system which includes longitudinal and pitch motion. Consider how accurate the filters must be to maintain a cross-coupling of < 3% in the 0.5-2 Hz band.
  5. Is this decoupling forsooth still maintained when you close the SUS damping loops in the model? If not, why so?
  6. Make step response measurements of the damping loops and record/plot data. Use physical units of um/urad for the y-axes. How much is the step response cross-coupling?
  7. Consider the IMC noise budget: are the low pass filters in the damping loops low-passing enough? How much damping is demasiado (considering the CMRR of the concrete slab for seismic waves)?
  8. Can we use Radhika's AAA representation to auto-tune the FF and damping filters? It would be very slick to be able to do this with one button click.

gautam: For those like me who don't know what the AAA representation is: the original algorithm is here, and Lee claims his implementation of it in IIRrational is better, see his slides.

  16829   Wed May 4 13:09:42 2022 AnchalUpdateBHDIMC table balanced again, IMC is locking, YARM is locking

[Paco, JC, Anchal]

We balanced the IMC table back again to point that got us 50% of nominal transmission from IMC. Then we tweaked the steering mirror for injection to IMC to get up to 90% of nominal transmission. Finally, we used WFS servo loop to get to the 100% nominal transmission from IMC. However, we found that the WFS loop has been compromised now. It eventually misaligns IMC if left running for a few minutes. This needs to be investigated and fixed.

Next steps:

  • Align X-arm cavity and regain flashing.
  • Fix the Oplev path for ITMX.
  • Tune POX11 phase angle to get an error signal with which we can lock the cavity.
  • Finish AS beam path setup.
  2977   Tue May 25 00:10:24 2010 ZachUpdateIOOIMC table leveled again

The IMC table had to be leveled again, for two reasons: 1) It was un-leveled when Jenne and Kiwamu removed an extra beam dump when they took the beam profile measurements, and 2) the stack of weights I had put there before was too tall to allow the beam to pass (I didn't realize that the BS chamber is offset a bit to the north, so the beam passes right over the NE edge of the IMC table).

First of all, I was wrong before when I said that the stack of weights was 4 blocks tall; it was 6 blocks tall. I re-leveled the table this afternoon by removing the top three blocks and placing them immediately south of the bottom three in the original stack, while also moving the circular weight north of its previous position. The table is now balanced roughly to within the tolerance of the bubble level I was using.

After the leveling, I tried to re-lock the modecleaner. Upon removing the beam block on the PSL table, I got some sort of resonance flashes on the MC TRANS monitor. With some minor adjustments to MC2&3, I was able to get a decent TEM00 mode to hit. The cavity wouldn't lock, so I went to the AP table and checked to make sure that the REFL beam was hitting the PD. It was, but the beam was very close to the edge of the focusing lens, so I moved the steering mirror slightly to make the situation a little better.

I then went to the control room to finish the by-now-mundane task of fine-tuning the MC lock, but today's was a worthier opponent. For some reason, the thing didn't want to lock for more than a few seconds at a time. I saw that the spot on MC2 was quite a bit off-center, so I ran the MC2_spot_xxx scripts to get it visually in place, then revisited the AP table to ensure that the REFL beam was still on the PD. No dice.

I don't know what was different. I had Ameristat over the opening between the tanks, with posters on top and on the sides (as usual), and I checked to ensure that the servo gains were at the appropriate levels. Joe pointed out that IOO VME was not responding, but we didn't seem to think that this was the problem (based on nothing I can put in words or stick figure cartoons), and the "alive" indicator on the Auto-Lock control in the MEDM screen was not blinking, as it usually is, but I don't know what bearing this has on anything.

I will try to lock again tomorrow.

 

  8108   Tue Feb 19 12:02:00 2013 JamieUpdateIOOIMC table levelling.

In order to address the issue of low MC1 OSEM voltages, Yuta and I looked at the IMC table levelling.  Looking with the bubble level, Yuta confirmed that the table was indeed out of level in the direction that would cause MC1 to move closer to it's cage, and therefore lower it's OSEM voltages.  Looking at the trends, it looks like the table was not well levelled after TT1 installation.  We should have been more careful, and we should have looked at the MC1/3 voltages after levelling.

Yuta moved weights around on the table to recover level with the bubble level.  Unfortunately this did not bring us back to good MC1 voltages.  We speculate that the table was maybe not perfectly level to begin with.  We decided to try to recover the MC1 OSEM voltages, rather than go solely with the bubble level, since we believe that the MC suspensions should be a good reference.  Yuta then moved weights around until we got the MC1/3 voltages back into an acceptable range.  The voltages are still not perfect, but I believe that they're acceptable.

The result is that, according to the bubble level, the IMC table is low towards MC2.  We are measuring spot positions now.  If the spot positions look ok, then I think we can live with this amount of skew.  Otherwise, we'll have to physically adjust the MC1 OSEMS.

Screenshot-Untitled_Window.png

  3874   Sat Nov 6 00:49:04 2010 KojiUpdateIOOIMC table work

[Suresh, Koji]

- Removed MCT optics in the IMC chamber

- Rotated MC1 and MC3 in clock-wise to debias the YAW bias offsets (-5V and -8V to -1.5V and -0.5V).

- Adjusted insertion of the MC1 OSEMs so as to have the outputs of about 1.0V.

- Locked to TEM00. Trying to get the beams at the center of the mirror using Yuta's A2L.

  17249   Wed Nov 9 11:07:16 2022 AnchalUpdateSUSIMC test

Following configurations were kept today morning:

Start Time Stop Time HEPA PSL Shutter WFS Loops

1352046006

08:19:48 PST
16:19:48 UTC

1352050278

09:31:00 PST
17:31:00 UTC

OFF OPEN OFF

1352050393

09:32:55 PST
17:32:55 UTC

1352054538

10:40:00 PST
18:40:00 UTC

OFF OPEN ON

1352054537

10:41:59 PST
18:41:59 UTC

1352058724

11:51:46 PST
19:51:46

OFF CLOSED OFF

f2a filters with Q=10 (FM3) were turned on all IMC optics.

  17289   Sun Nov 20 13:42:21 2022 AnchalUpdateSUSIMC test

I repeated this test for the following configuration:

  • PSL shutter closed at good IMC transmission
  • Offset value of 14000 written to C1:IOO-MC_TRANS_SUM_FILT_OFFSET
  • WFS loops ON but ASCPIT outputs of the optics were turned off.

The test ran for 4000 seconds between following timestamps:

start time: 1352878206
stop time: 1352882207

This script was used to run this test and can be used again in future to repeat the same test.

  17232   Mon Nov 7 12:02:15 2022 AnchalUpdateSUSIMC test with PSL shutter closed.

Following configurations were kept today morning:

Start Time Stop Time HEPA PSL Shutter MC1 f2a MC2 f2a MC3 f2a MC3 ringing Notes

1351879503

10:04:45 PST
18:04:45 UTC

1351879797

10:09:39 PST
18:09:39 UTC

ON OFF ON ON ON NO Found later that MC3 started ringing at 1351879797

1351879797

10:09:39 PST
18:09:39 UTC

1351881325

10:35:07 PST
18:35:07 UTC

ON OFF ON ON ON YES This is the duration when MC3 was ringing

1351881325

10:35:07 PST
18:35:07 UTC

1351882257

10:50:39 PST
18:50:39

OFF OFF ON ON ON YES We turned off HEPA filter during this time, MC3 was still ringing.

1351882257

10:50:39 PST
18:50:39 UTC

1351882346

10:52:08 PST
18:52:08 UTC

OFF OFF ON ON ON NO I noticed MC3 rining and reset f2a filter by turning it off, waiting for it to damp down and restarting it.

1351882346

10:52:08 PST
18:52:08 UTC

1351883406

11:09:48 PST
19:09:48 UTC

OFF OFF ON ON ON YES MC3 started ringing again soon.

1351883406

11:09:48 PST
19:09:48 UTC

1351885490

11:44:32 PST
19:44:32 UTC

OFF OFF ON ON OFF NO MC3 f2a filters turned off due to repeated failure.

1351885490

11:44:32 PST
19:44:32 UTC

1351887487

12:17:49 PST
20:17:49 UTC

ON OFF ON ON OFF NO Turned ON HEPA for completeness of data.

 

  10662   Mon Nov 3 17:14:00 2014 ericqUpdateASCIMC to IFO angular motion

Something to note, as we have the IMC angular controls under consideration:

Jenne has the DRMI locked right now. I took a look at the coherence between the POP QPD and MC2 transmission QPDs. (Since she's using ASC, I also included those control signals. The coherences are about the same, unsurprisingly)

Based on the observed coherences, from about 1 to 6Hz, IMC motion is responsible for a fair amount of the DRMI angular motion. Also, PIT and YAW couple differently. 

2014-10-03-MC2T_to_POPQPD.pdf

  10663   Mon Nov 3 17:43:14 2014 KojiUpdateASCIMC to IFO angular motion

I wonder if this is the coherence caused by the beam itself, or caused by the same ground motion.
Jenne should be able to tell us...

  14335   Fri Dec 7 17:04:18 2018 gautamUpdateIOOIMC transmission
  • Power just before PSL shutter on PSL table = 97 +/- 1 mW. Systematic error unknown.
  • Power from IFO REFL on AP table = 40 +/- 1 mW. Systematic error unknown.

Both were measured using the FieldMate power meter. I was hesitant to use the Ophir power meter as there is a label on it that warns against exceeding 100 mW. I can't find anything in the elog/wiki about the measured inesrtion loss / isolation of the input faraday, but this seems like a pretty low amount of light to get back from PRM. The IMC visibility using the MC_REFL DC values is ~87%. Assuming perfect transmission of the 87% of the 97mW that's coupled into the IMC, and assuming a further 5% loss between the Faraday rejected port and the AP table, the Faraday insertion loss would be ~30%. Realistically, the IMC transmission is lower. There is also some part of the light picked off for IPPOS. Judging by the shape of the REFL spot on the camera, it doesn't look clipped to me.

Either way, seems like we are only getting ~half of the 1W we send in on the back of PRM. So maybe it's worth it to investigate the situation in the IOO chamber during this vent.


c1pslc1susaux,c1iool0,caux  crates were keyed. Also, the physical shutter on the PSL NPRO, which was closed last Monday for the Sundance crew filming, was opened and the PMC was locked. PMC remains locked, but there is no light going into the IMC.

  16705   Mon Mar 7 10:06:32 2022 YehonathanUpdateIOOIMC unlocked again, completely misaligned

Came this morning and saw that the IMC is unlocked.

Went into MC Lock screen and see that the watchdog is down and the PSL shutter is closed. I tried to open the shutter but nothing happened - no REFL signal or beam on the MC REFL camera .

Thinking this has something to do with the watchdog I upped the watchdog:

ezcawrite C1:SUS-MC2_LATCH_OFF 1

The watchdog on the MEDM screen became green but the shutter still seemed unresponsive. I went to the PSL table and made sure that the shutter is working. I opened the AS table and saw there no MC REFL beam anywhere.

Thinking that MC1 must be completely misaligned I opened the MC align screen to find that indeed all the alignment values has been zeroed! (attachment).

I burt restore c1iooepics from Mar 4th 00:19. Didn't help.

I try to burt restore c1susepics from Mar 1st 13:19. Still zero.

I try to burt restore c1susaux from Mar 1st 00:19 -> seems like alignment values have been restored.

I open the shutter. Beam is flying! MC Watchdogs tripped! I close the shutter. OK, I need to wait until the MCs are dampped enough. MC2 and MC3 have relaxed so I enable their watchdogs. MC1 is still swinging a bit. I turn on damping for MC1 as well.

 

MC locked immediately but the REFL is still high like 1.2. Is it normal?

I turn on the WFSs and the REFL went down to 0.3 nice. I run the MC WFS relief script.

Attachment 1: Screenshot_2022-03-07_10-15-19.png
Screenshot_2022-03-07_10-15-19.png
  16708   Mon Mar 7 14:55:33 2022 KojiUpdateIOOIMC unlocked again, completely misaligned

Hmm, the bias values were reset at 2022-03-03-20:01UTC which is 2022-03-03-12:01 PST with no apparent disruption of the data acquisition (= no resetting of the RTS). Not sure how this could happen.

 

  13055   Fri Jun 9 15:31:45 2017 gautamUpdateIMCIMC wonkiness

I've been noticing some weird behaviour with the IMC over the last couple of days. In some lock stretches the WFS control signals ramp up to uncharacteristically huge values - at some point, the IMC loses lock, and doesn't re-acquire it (see Attachment #1). The fact that the IMC doesn't re-acquire lock indicates that there has been some kind of large alignment drift (this is also evident from looking at the (weak) flashes on the MCREFL camera while the IMC attempts to re-lock - I am asking Steve to restore the MC trans camera as well). These drifts don't seem to be correlated with anyone working near MC2.

The WFS servos haven't had their offsets/ DC alignments set in a while, so in order to check if these were to blame, I turned off the inputs to all the WFS servo filter modules (so no angular control of the IMC). I then tweaked the alignment manually. But the alignment seems to have drifted yet again, within a few minutes. Looking at the OSEM sensor signals, it looks like MC2 was the optic that drifted. Steve tells me no one was working near MC2 during this time. But the drift is gradual so this doesn't look like the infamous glitchy Satellite Box problem seen with MC1 in the recent past. The feedback signal to the NPRO / PCdrive look normal during this time, supporting the hypothesis that the problem is indeed related to angular alignment.

Once Steve restores the MC2 Trans cameras, I will hand-align the IMC again and see if the alignment holds for a few hours. If it does, I will reset all offsets for the WFS loops and see if they hold. In particular, the MC2 transmitted spot centering servo has a long time constant so could be something funny there.

*Another issue with the IMC autolocker I've noticed in the recent past: sometimes, the mcup script doesn't get run even though the MC catches a TEM00 mode. So the IMC servo remains in acquisition state (e.g. boosts and WFS servos don't get turned on). Looking at the autolocker log doesn't shed much light - the "saw a flash" log message gets printed, but while normally the mcup script gets run at this point, in these cases, the MC just remains in this weird state. 

Attachment 1: IMG_7409.JPG
IMG_7409.JPG
  13057   Fri Jun 9 17:45:21 2017 Gautam, KaustubhUpdateIMCIMC wonkiness

 

Quote:

Once Steve restores the MC2 Trans cameras, I will hand-align the IMC again and see if the alignment holds for a few hours. If it does, I will reset all offsets for the WFS loops and see if they hold. In particular, the MC2 transmitted spot centering servo has a long time constant so could be something funny there.

 

Summary:

In order to switch on the angular alignment for the IMC mirrors, we needed to center the laser onto the quad-photodiodes at the IMC and the AS Table(WFS1 and WFS2)

I and Gautam went to the IMC table and did the dc centering for the quad-photodiode by varying the beamsplitter angles. After this, we turned the WFS loops off and performed beam centering for the Quad PDs at the AS Table, the WFS1 and WFS2.

Once we had the beam approximately centered for all of the above 3 PDs, we turned on the locking for IMC, and it seems to work just fine. We are waiting for another hour for switching on the angular allignment for the mirrors to make sure the alignment holds with WFS turned off.

  13058   Fri Jun 9 19:18:10 2017 gautamUpdateIMCIMC wonkiness

It happened again. MC2 UL seems to have gotten the biggest glitch. It's a rather small jump in the signal level compared to what I have seen in the recent past in connection with suspect Satellite boxes, and LL and UR sensors barely see it.

I will squish Sat box cables and check the cabling at the coil driver board end as well, given that these are two areas where there has been some work recently. WFS loops will remain off till I figure this out. At least the (newly centered) DC spot positions on the WFS and MC2 TRANS QPD should serve as some kind of reference for good MC alignment.

GV edit 9pm: I tightened up all the cables, but doesn't seem to have helped. There was another, larger glitch just now. UR and LL basically don't see it at all (see Attachment #2). It also seems to be a much slower process than the glitches seen on MC1, with the misalignment happening over a few seconds (it is also a lot slower). I have to see if this is consistent with a glitch in the bias voltage to one of the coils which gets low passed by a 4xpole@1Hz filter.

Quote:

Once we had the beam approximately centered for all of the above 3 PDs, we turned on the locking for IMC, and it seems to work just fine. We are waiting for another hour for switching on the angular allignment for the mirrors to make sure the alignment holds with WFS turned off.

 

Attachment 1: MC2_UL_glitchy.png
MC2_UL_glitchy.png
Attachment 2: MC2_glitch_fast.png
MC2_glitch_fast.png
  13061   Mon Jun 12 22:23:20 2017 ranaUpdateIMCIMC wonkiness

wonder if its possible that the slow glitches in MC are just glitches in MC2 trans QPD? Steve sometimes dances on top of the MC2 chamber when he adjusts the MC2 camera.

I've re-enabled the WFS at 22:25 (I think Gautam had them off as part of the MC2 glitch investigation). WFS1 spot position seems way off in pitch & yaw.

From the turn on transient, it seems that the cross-coupled loops have a time constant of ~3 minutes for the MC2 spot, so maybe that's not consistent with the ~30 second long steps seen earlier.

  13062   Tue Jun 13 08:40:32 2017 SteveUpdateIMCIMC wonkiness

Happy MC after last glitch at 10:28 so the credit goes to Rana

GV edit 11:30am: I think the stuff at 10:28 is not a glitch but just the WFS servos coming on - the IMC was only hand aligned before this.

Quote:

It happened again. MC2 UL seems to have gotten the biggest glitch. It's a rather small jump in the signal level compared to what I have seen in the recent past in connection with suspect Satellite boxes, and LL and UR sensors barely see it.

I will squish Sat box cables and check the cabling at the coil driver board end as well, given that these are two areas where there has been some work recently. WFS loops will remain off till I figure this out. At least the (newly centered) DC spot positions on the WFS and MC2 TRANS QPD should serve as some kind of reference for good MC alignment.

GV edit 9pm: I tightened up all the cables, but doesn't seem to have helped. There was another, larger glitch just now. UR and LL basically don't see it at all (see Attachment #2). It also seems to be a much slower process than the glitches seen on MC1, with the misalignment happening over a few seconds (it is also a lot slower). I have to see if this is consistent with a glitch in the bias voltage to one of the coils which gets low passed by a 4xpole@1Hz filter.

Quote:

Once we had the beam approximately centered for all of the above 3 PDs, we turned on the locking for IMC, and it seems to work just fine. We are waiting for another hour for switching on the angular allignment for the mirrors to make sure the alignment holds with WFS turned off.

 

 

Attachment 1: happy_MC.png
happy_MC.png
Attachment 2: last_glitch.png
last_glitch.png
  11436   Wed Jul 22 15:09:40 2015 ericqUpdateGeneralIMC work

The other night, I spent some time with the mode cleaner. 

First, I made some model changes to the MC_TRANS part of c1mcs.mdl. Specifically, I brought in the userapps QPD part that we are using for the transmon and oplev QPDs. My main motivation for doing so was to have FMs for the pitch and yaw values, to be able to set offsets. Up until now, we have used a QPD centering servo in conjunction with the WFS, but the center of the QPD is not perfectly aligned to represent the center of MC2. Using offsets at the servo isn't really practical, since there are integrators. 

I then spent some time manually aligning the mode cleaner mirrors with WFS off, followed by centering the in-lock MC REFL beam on the WFS QPDs, and setting the WFS and MC_TRANS offsets. (I updated the WFS offset script, and made one for MC_TRANS in scripts/MC/WFS. They now use averaging instead of servoing to zero, a la LSC PD offset script). 

The resultant intracavity power and RIN was an improvement over the older offsets. (RMS RIN went down by half, I think.)

Since Monday, the autolocker seems to be having some trouble. At first, I suspected the changes I made weren't so hot after all, but I've now noticed a pattern. Often when I come to manually lock the mode cleaner due to a long unlocked period, I find that the sliders are not in the state specified by the mcdown script. Furthermore, it's not the same channels every time; sometimes the servo gain is left high, sometimes the boosts are left on. I fear that some of the caput commands are failing to execute. Ugh. 

  11486   Mon Aug 10 11:57:45 2015 ericqUpdateGeneralIMC work
Quote:

Often when I come to manually lock the mode cleaner due to a long unlocked period, I find that the sliders are not in the state specified by the mcdown script. Furthermore, it's not the same channels every time; sometimes the servo gain is left high, sometimes the boosts are left on. I fear that some of the caput commands are failing to execute. Ugh. 

This continues to happen. I believe the network latency boogeyman is to blame. 

There was a long unlocked period because the enable switch for the MC servo fast path (FASTSW) was left off. Running the mcdown script fixed this, but included the error message:

Channel connect timed out: 'C1:IOO-MC_REFL_GAIN' not found.
CA Client Library: Ignored duplicate create channel response from CA server?

which means the IN1 gain didn't get touched. A second pass of the script produced no errors. 

I'm thinking of adding some logic that if the autolocker has failed to lock for some period (5 minutes?), it should rerun mcdown. 

  13278   Thu Aug 31 00:19:35 2017 rana[^r]UpdatePSLIMC/FSS FAST gain

nominal changed from 22 to 23 dB to minimize PC drive RMS

previous loop gain measurement is sort of bogus (made on SR785); need some 4395 loop measurements and checking of crossover and error point spectrum

  12875   Thu Mar 9 15:25:12 2017 KojiUpdateGeneralIMC/XYarms aligned/locked

As per Steve's request, I've checked the alignment of the IMC and the arms. These three cavities are locked and aligned.

  3797   Wed Oct 27 15:38:19 2010 josephb, yutaUpdateCDSIO chassis with bad timing was taken back to Downs

Problem:

The front end timing was not working properly for 2 of the IO chassis.  They were not being synced to the 1 PPS signal. 

This prevented the use of RFM for communication between front ends because time stamps on the transmitted data did not match the cycle on the receiving machine.

Action:

We took one of the incorrectly working chassis over to Downs.  Rolf said he would take a look at it tomorrow morning.

Joe will be going over tomorrow morning to talk with Rolf and see what needs to be done to fix it.

 

  6676   Thu May 24 15:10:43 2012 SureshSummaryGeneralIOO (MC) health check webpage layout

   Here is the suggested layout of the MC health check web page layout. I will update the Omnigraffle file as people comment and suggest changes.  If you want the file let me know.

 

MC_Health_Check.pdf

  11296   Sun May 17 23:46:25 2015 ranaUpdateASCIOO / Arm trends

Looking at the summary page trends from today, you can see that the MC transmission is pretty flat after I zeroed the MCWFS offsets. In addition, the transmission from both arms is also flat, indicating that our previous observation of long term drift in the Y arm transmission probably had more to do with bad Y-arm initial alignment than unbalanced ETMY coil-magnets.

Much like checking the N2 pressure, amount of coffee beans, frames backups, etc. we should put MC WFS offset adjustment into our periodic checklist. Would be good to have a reminder system that pings us to check these items and wait for confirmation that we have done so.

  11360   Mon Jun 15 20:36:48 2015 ranaUpdateIOOIOO QPDs centred

after re-aligning the beam into the PMC, I touched up the steering mirros into the IOO QPDs so that the beams are now centered again. Please don't adjust these references without prior authorization and training.

This plot shows the 10-minute trends for these QPDs over the last 400 days.

Attachment 1: Untitled.png
Untitled.png
  1443   Mon Mar 30 12:46:36 2009 YoichiConfigurationIOOIOO QPDs were missing the beam
When I re-locked the MC, I wanted to check the trend of the IOO QPDs to see if the input beam pointing has changed.
Then I found that the QPDs were not receiving light.
The attached trend plots show that the QPDs missed the beam on March 23rd.
The IOO-QPD_ANG was installed on Mar 11th by Kiwamu and Kakeru. Since then, they were serving as a reference of the PSL beam pointing.
But there is no record of the past week. This is very bad because then I cannot tell if I should relieve the MC WFS to make the mirrors follow the input beam or not.
I found that someone has moved the beam splitter which picks up the beam going to those QPDs. But there is no elog entry on this around March 23rd.
I re-centered the beam on the QPDs.

Since the X-arm locked to TEM00 with the MC WFS on (i.e. the MC beam axis is following the input beam axis), I guessed that the input beam has not drifted that much. So I relieved the WFS and centered the WFS QPDs.
Attachment 1: IOO-QPDs.pdf
IOO-QPDs.pdf
  9577   Mon Jan 27 12:26:00 2014 KojiUpdateIOOIOO Slow Actuator Servo threshold changed

In order to activate the slow actuator servo for the MC locking,
the threshold level for this servo (C1:PSL-FSS_LOCKEDLEVEL) was changed from 10000 to 700.

Now the servo started to move the PZT fast out to be controlled to 5V.

  10526   Tue Sep 23 09:37:12 2014 SteveUpdateSUSIOO and temp changes
Attachment 1: IOO.png
IOO.png
  5907   Wed Nov 16 10:11:20 2011 steveUpdatePSLIOO angle & pos qpd centered

Quote:

This moring I centered the IOO Angle QPD. The IOO Pos QPD was not centered. The existing layout does not allow the beam centering of the Pos qpd without misaligning the MC

input. We have to add an aditional steering mirror. I will do that tomorrow morning.

 I added the steering mirror for Pos  and centered both qpds

Attachment 1: iooqpds.png
iooqpds.png
  5898   Tue Nov 15 16:25:38 2011 steveUpdatePSLIOO angle qpd centered

This moring I centered the IOO Angle QPD. The IOO Pos QPD was not centered. The existing layout does not allow the beam centering of the Pos qpd without misaligning the MC

input. We have to add an aditional steering mirror. I will do that tomorrow morning.

  5912   Wed Nov 16 14:34:18 2011 steveUpdatePSLIOO beam moves in pitch

C1:IOO-QPD_ANG_VERT beam movement  in 1 degree C temp change in 3 hrs

 

Attachment 1: iooqpds.png
iooqpds.png
  9705   Mon Mar 10 09:28:48 2014 steveUpdateIOOIOO pointing 2 days

 Morning seconds without adjustment.

 

Attachment 1: IOOpointing2d.png
IOOpointing2d.png
Attachment 2: morningseconds.png
morningseconds.png
  9704   Fri Mar 7 16:56:17 2014 steveUpdateIOOIOO qpds centered

Quote:

Quote:

The IMC has not been behaving well since this morning and totally not happy when Q was finishing his measurements. The WFS servo had large offsets in pitch. Looking back at the trend and using ezcaservo to restore the suspensions did not help.

I realigned the IMC and brought TRANS SUM to ~18000 and MCREFL to < 0.5. The spot positions are not very good; nearly 2 mm off in pitch on MC1 and MC3. But after the alignment of MC, the WFS servo offsets were below +/-20.

The MC has been locked stably with WFS servo ON for the last few hours.

P.S. I did not touch the WFS pointing or reset the WFS offsets.

MC remained locked with WFS enabled all through last night and this morning. Koji dropped by and looked at the MC. The MC WFS servo, though stable, was at the edge of becoming unstable. This was because I did not touch the WFS pointing on the QPDs yesterday after realigning. So I recentered the WFS, reset the WFS filterbank offsets and reenabled the servo.

I measured the spot positions on MC mirrors for reference.

Spot positions in mm (MC1,2,3 pit MC1,2,3 yaw): [1.405767579680834, 0.79369009503571208, 1.3220430681427462, -1.2937873599406551, -1.1704264340968924, -1.2518046122798692]

 

Attachment 1: IOOqpdCentered.png
IOOqpdCentered.png
  9350   Tue Nov 5 19:50:07 2013 manasaUpdateElectronicsIOO rack +/-5V power supplies

The power supply to the ADC box on the IOO rack (that reads the beat I & Q signals) was pulled out because it did not run through any fuse and was connected directly to the power supply. 

There were already connections running from the +/-5 V power supply. They were powering the mode cleaner demod board rack. In order to remove the ADC power connectors from the power supply, I notified Jenne in the control room because turning off the power supply would affect the MC. I switched off the +/-5V power supplies at the same time. The ADC power connectors were removed. The +/-5V power supplies were then turned ON again at the same time. Jenne relocked the MC after this.

I have still not connected the ADC to the fuse rack power supply because this requires the +/-5V power supplies to be turned OFF again in order to pull out new connections from the fuse rack and I need to make a new ADC power connector with thicker wires.

  9356   Wed Nov 6 15:59:41 2013 manasaUpdateElectronicsIOO rack +/-5V power supplies

Quote:

The power supply to the ADC box on the IOO rack (that reads the beat I & Q signals) was pulled out because it did not run through any fuse and was connected directly to the power supply. 

There were already connections running from the +/-5 V power supply. They were powering the mode cleaner demod board rack. In order to remove the ADC power connectors from the power supply, I notified Jenne in the control room because turning off the power supply would affect the MC. I switched off the +/-5V power supplies at the same time. The ADC power connectors were removed. The +/-5V power supplies were then turned ON again at the same time. Jenne relocked the MC after this.

I have still not connected the ADC to the fuse rack power supply because this requires the +/-5V power supplies to be turned OFF again in order to pull out new connections from the fuse rack and I need to make a new ADC power connector with thicker wires.

I switched OFF the +/-5V power supplies on the IOO rack to hook up the ADC power connectors through 250mA fuses to +/-5V. Since these power supplies were powering the MC demod boards, MC remained unlocked during the process. I turned the power supplies back ON and MC relocked itself after this.

  10954   Thu Jan 29 09:50:47 2015 manasaUpdateElectronicsIOO rack amplifier panel

The RF amplifier panel on the IOO rack (Attachment 1) will be used to also hold the RF amplfiers for the frequency counters. The amplifiers mounted on it right now are getting +15 (orange wire) and GND (black wire) from the rack power supply (Attachment 2).

Proposed plan to install RF amplifiers:

1. Disconnect the D sub connector that powers the amplifiers and pull out the panel. The rack power supplies will NOT be shut down for this. 

2. Mount the RF amplifiers with bypass capacitors. There will be 4 amplifiers ZFL-500LN mounted on the same panel (2 for each frequency counter).

3. While putting back the panel on the IOO rack, we will need to shut down the +15V and -15V sources to connect the amplifiers to the rack power supply.

I will do this over this weekend so that we dont lose any locking time. If anybody has any concerns, let me know

Attachment 1: panel_front.jpg
panel_front.jpg
Attachment 2: panel_back.jpg
panel_back.jpg
  939   Wed Sep 10 13:28:25 2008 YoichiSummaryElectronicsIOO rack lost -24V (recovered)
Alberto, Yoichi

This morning, the MC suddenly started to be unwilling to lock.
I found a large offset in the MC servo board.
It turned out that -24V was not supplied to the Eurocard crate of the IOO rack.
We found two loose cables (violet, that means -24V) around the cross connects with fuses.
We connected them back, and the -24V was back.
The MC locks fine now, and Alberto can continue his arm length experiment.
  11079   Thu Feb 26 16:46:37 2015 manasaUpdateGeneralIOO rack power supply

I shutdown the +/-15V and the +/-24V sorensons on the IOO rack to connect the FOL RF PDs to the rack power supply.

They were turned back ON after the work. PMC and MC were relocked.

Quote:

[Steve, Manasa]

We ran power cables and sma cables for the FOL fiber module from the PSL table to the IOO rack.

 

  9678   Wed Feb 26 10:08:14 2014 SteveUpdateIOOIOO trend

 

 The MC is happy (but only for this tiny snapshot in time and most probably will go dysfunctional again as it has been for several months, as of this writing)

Attachment 1: IOOtrend3&24h.png
IOOtrend3&24h.png
  600   Mon Jun 30 08:59:23 2008 steveUpdateIOOIOO-MC_DEMOD_LO is low
The alarm handler is beeping relentlessly: asking for help in high partical count and low demod signal
Attachment 1: demlo.jpg_____
demlo.jpg_____
  7069   Wed Aug 1 15:02:29 2012 JenneUpdateIOOIP POS QPD centered

Jamie went out to look at IP POS, and the beam was *way* off.  Even though our alignment is still rough, we're kind of close right now, so Jamie put the beam back on the QPD, but we need to recenter IPPOS after we get good alignment.

  5459   Mon Sep 19 14:57:36 2011 kiwamuSummaryIOOIP POS is back

IPPOS is back. A cable had been disconnected at the 1Y2 rack. So I put it back to place.

The cartoon below shows the current wiring diagram. I think this configuration is exactly the same as it it used to be.

wiring.png

Quote from #5455

  + Fixing IPPOS (volunteers) 

  2110   Sun Oct 18 19:55:45 2009 ranaConfigurationElectronicsIP POS is back: ND filter gone, new resistors in

Its back in and re-centered. Our next move on IPPOS should be to replace its steering mirror with something bigger and more rigid.

Electronics changes:

20K -> 3.65 K  (R6, R20, R42, R31) (unused)

20K -> 3.65 K  (R7, R21, R32, R43, R11, R24, R35, R46)

If you look in the schematic (D990272), you see that its an AD797 transimpedance stage with a couple of LT1125 stages set to give some switchable gain. It looks like some of these

switches are on and some are not, but I am not sure where it would be controlled from. I've attached a snapshot of one quadrant of the schematic below.

The schematic shows the switches in the so-called 'normally closed' configuration. This is what the switches do with zero volts applied to the control inputs. As the schematic also shows,

just disconnecting the 'switch' inputs cause the switch's control inputs to go high (normally open configuration, i.e. pins 2-3 connected, pin4 open). For the record, the default positions of the IPPOS switches are:

switch1   high

switch2   low

switch3   low

switch4   high

 


** EDIT (Nov 2, 2009): I forgot to attach the before and after images; here they are:

IMG_0068.JPGIMG_0072.JPG

  2112   Sun Oct 18 22:06:15 2009 ranaConfigurationElectronicsIP POS is back: ND filter gone, new resistors in

I tried to compare the IP_POS time series with the IPANG and MC_TRANS but was foiled at first:

1) The IPANG scan rate was set to 0.5 second, so it doesn't resolve the pendulum motions well. Fixed in the .db file.

2) Someone had used a Windows/DOS editor to edit the .db file and it was filled with "^M" characters. I have removed them all using this command:   tr -d "\r" <ETMXaux.db > new.db

3) The MC_TRANS P/Y channels were on the MC Lock screen but had never been added to the DAQ. Remember, if there's a useful readback on an EPICS screen. its not necessarily in the frames unless you add it to the C0EDCU file. I have done that now and restarted the fb daqd. Channels now exist.

4) Changed the PREC of the IPPOS channels to 3 from 2.

5) changed the sign for the IBQPD (aka IPANG) so that bigger signal is positive on the EPICS screen.

Attachment 1: Untitled.png
Untitled.png
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