40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log, Page 238 of 335  Not logged in ELOG logo
ID Date Author Type Category Subjectup
  10746   Tue Dec 2 02:44:45 2014 JenneUpdateLSCTried cav pole compensation trick - fail

[Jenne, Diego]

First, random notes:

  • saw a violin peak in CARM / DARM at 638.0Hz.  Assumed it was one of the ETMs, even though it doesn't match any of the frequencies in our handy-dandy chart: wiki resonances
    • Put an extra notch in the ETM violin filters.
    • Just now realized that I was actuating MC2 at the time for CARM (although 638 is also not what we have in the chart for MC2).  The MC2/ETM violin filters should be shared between eachother.
  • Measured CARM and DARM loops on ALS comm and diff, gains should be 8, not 6.  Fixed in Lock_ALS_CARM_and_DARM script. 
  • MC has been fussy tonight.  I started actuating CARM on ETMs, and that helped, but we've still had several unexplained MC locklosses. 
    • PC and FSS Slow are okay right now, but they have been mad earlier tonight.  Do we need to check the PID tuning for FSS slow?
  • When I first started locking this evening, I was able to hold nice high arm powers (with the usual factor of 2+ RIN), so the IFO seemed okay except for the fussy MC.

Koji suggested last week that we put a cavity pole filter into the ALS error signals, and then compensate for that in the CARM and DARM servos.  The idea is that any RF signals we want to transfer to will have some kind of frequency dependence, and at the final zero CARM offset that will be a simple cavity pole. 

I put a pole at 200 Hz, with a zero at 6 kHz into the LSC-ALS[X,Y] filter banks in FM1, and then also put a zero at 200 Hz with a pole at 6 kHz into both the CARM and DARM servos at FM7.  Ideally I wouldn't have the 6kHz in there, but the compensation filter in the CARM/DARM servos needs a pole somewhere, so I put in the zero in the ALS signals so that they match.  Foton thinks that multiplying the two filters should give a flat response, to within 1e-6dB and 1e-6 deg. 

We can lock CARM and DARM on ALS with the new filters, but it seems to be not very stable.  We've measured transfer functions in both configurations, and between 50-500Hz, there is no difference (i.e., our matching filters are matching, and cancelling each other out).  We sometimes spontaneously lose lock when we're just sitting somewhere with the new configuration, and we cannot run any find IR resonance scripts and stay locked.  We've tried the regular old script, as well as Diego's new gentler script.  We always fail with the regular script during the coarse scan.  With Diego's script, we made it through the coarse scan, but spontaneously lost lock while the script was calculating the location of the peak.  So, we determine that there is something unstable about the new configuration that we don't understand.  Turning off all the new filters and going back to the old configuration is just as robust as always.  Confusing. 

 

  10748   Wed Dec 3 01:46:12 2014 KojiUpdateLSCTried cav pole compensation trick - fail

Where did these 200Hz, 6kHz come from?


I wonder what are the correct filters to be incorporated in the filter banks for the cav pole compensarion.

Facts:

1. ALS Common and Diff have the cavity pole for the green (fcav_GR)

2. IR DARM has the cavity pole of the arms for IR (fcav_IR_DARM)

3. IR CARM (REFL, POP, POX, or POY) has the double cavity pole (fcav_IR_CARM)

Calculations:

1. T(ITM_GR) = 1.094%, T(ETM_GR) = 4.579% => F=108.6 (cf. https://wiki-40m.ligo.caltech.edu/Core_Optics)
L = 37.8 m (cf. http://nodus.ligo.caltech.edu:8080/40m/9804)
=> fcav_GR = c /( 4 L F) = 18.3 kHz ... ignore

2. T(ITM_IR) = 1.384%, T(ETM_IR) = 13.7ppm => F=450.4
=> fcav_IR_DARM = 4.40 kHz

3. The common cavity pole is lower than fcav_IR by factor of power recycling gain.
=> fcav_IR_CARM = fcav_IR / (P_TR * T_PRM)
P_TR is normalized for the locked arm cavity with the PRM misaligned.
T_PRM is 5.637%

e.g. for the TR of 100, fcav_IR_CARM = 4.40/(100*0.05637) = 780Hz

                         (IR CARM) o--|
                                      +--[CARM 780Hz zero / ??? pole]
(ALSX) o--|   |-[ALS C 780Hz pole]----|
          | M |
(ALSY) o--|   |-[ALS D 4.40kHz pole]--|
                                      +--[DARM 4.40kHz zero / ??? pole]
                         (IR DARM) o--|

???Hz pole is to ensure the servo filters does not have infinite gain at f=infinite, but in practice we probably can ignore it as long as it is provided by a roll-off filter

  16232   Wed Jun 30 18:44:11 2021 AnchalSummaryLSCTried fixing ETMY QPD

I worked in Yend station, trying to get the ETMY QPD to work properly. When I started, only one (quadrant #3) of the 4 quadrants were seeing any lights. By just changing the beam splitter that reflects some light off to the QPD, I was able to get some amount of light in quadrant #2. However, no amount of steering would show any light in any other quadrants.

The only reason I could think of is that the incoming beam gets partially clipped as it seems to be hitting the beam splitter near the top edge. So for this to work properly, a mirror upstream needs to be adjusted which would change the alignment of TRX photodiode. Without the light on TRX photodiode, there is no lock and there is no light. So one can't steer this beam without lossing lock.

I tried one trick, in which, I changed the YARM lock trigger to POY DC signal. I got it to work to get the lock going even when TRY was covered by a beam finder card. However, this lock was still bit finicky and would loose lock very frequently. It didn't seem worth it to potentially break the YARM locking system for ETMY QPD before running this by anyone and this late in evening. So I reset everything to how it was (except the beam splitter that reflects light to EMTY QPD. That now has equal ligth falling on quadrant #2 and #3.

The settings I temporarily changed were:

  • C1:LSC-TRIG_MTRX_7_10 changed from 0 to -1 (uses POY DC as trigger)
  • C1:LSC-TRIG_MTRX_7_13 changed from 1 to 0 (stops using TRY DC as trigger)
  • C1:LSC-YARM_TRIG_THRESH_ON changed from 0.3 to -22
  • C1:LSC-YARM_TRIG_THRESH_OFF changed from 0.1 to -23.6
  • C1:LSC-YARM_FM_TRIG_THRESH_ON changed from 0.5 to -22
  • C1:LSC-YARM_FM_TRIG_THRESH_OFF changed from 0.1 to -23.6

All these were reverted back to there previous values manually at the end.

 

  5575   Thu Sep 29 11:25:55 2011 JenneUpdateAdaptive FilteringTried new c-code, Fail.

[Mirko, Jenne]

Mirko edited the c-code to use Den's stuff that he put in the elog last night.  We then tried to compile and install, but it crashed c1lsc again.  We reverted to the simple, working c-code, pushed the physical reset button on c1lsc, and things started getting better.  The suspensions had the same problem as last night...we had to do a soft shutdown of c1sus to get things better again. 

I did a by-hand burt restore for all of the models on c1lsc and c1sus, since the auto burt restore isn't working.

  5878   Fri Nov 11 22:07:43 2011 SureshUpdateIOOTried to recover the MC alignment of 4th Nov: partial success, PSL beam clipping

I have recovered the yaw values pretty much .  As the PZT1 rails in this direction perhaps this is the more relevant of the two alignments.  The beam is translated in the vertical direction, but this can be easily corrected by changing the pitch of MC2

However note that if the WFS are switched on .. MC is going to follow the PSL beam. 

 

 

 Date  #### MC1P MC2P MC3P MC1Y MC2Y MC3Y
03Nov2011   0.1354 -0.2522 -0.1383 -1.0893 0.7122 -1.5587
04Nov2011   4.0411 4.4994 3.5564 -1.4170 -0.2606 -1.7109
08Nov2011   4.7341 4.8794  4.3907 1.3542 -3.0508 -1.7167
10Nov2011    1   3.9944 3.7676 6.1001 -1.3058 -3.8087 -1.6418
11Nov2011    1  3.8542 3.6831 3.0418 -0.8383 0.1550 -2.3841
11Nov2011    2    3.6876 2.7429 2.7830 -1.6250 -0.0386 -1.6346

 

 

  14117   Mon Jul 30 16:11:54 2018 gautamUpdateSUSTrillium interface box is broken

[koji, steve, gautam]

We debugged this in the following way:

  1. Disconnect all fuses in the terminal blocks coming from the +/- 20 VDC Sorensens.
  2. Check that they are indeed isolated using DMM.
  3. Test blocks of fuses in order to identify where the problem is happening (i.e. plug fuses in, turn up Sorensen voltage knobs, look for current overload). We did things in the following order:
    • MC suspensions
    • BS, PRM and SRM
    • ITMY
    • ITMX
    • Trillium interface box.
  4. Turns out that the Trillium box is the culprit.
  5. Confirmed that the problem is in the trillium interface box and not in the seismometer itself by unplugging all cables leading out of the interface box, and checking that the problem persists when the box is powered on.

So for now, the power cable to the box is disconnected on the back end. We have to pull it out and debug it at some point.

Apart from this, megatron was un-sshable so I had to hard reboot it, and restart the MCautolocker, FSSslowPy and nds2 processes on it. I also restarted the modbusIOC processes for the PSL channels on c1auxex (for which the physical Acromag units sit in 1X5 and hence were affected by our work), mainly so that the FSS_RMTEMP channel worked again. Now, IMC autolocker is working fine, arms are locked (we can recover TRX and TRY~1.0), and everything seems to be back to a nominal state. Phew.

  14118   Mon Jul 30 18:19:03 2018 KojiUpdateSUSTrillium interface box was fixed and reinstalled

The trillium interface box was removed from the rack.

The problem was the incorrect use of an under-spec TVS (Transient Voltage Suppression) diodes (~ semiconductor fuse) for the protection circuit.
The TVS diodes we had had the breakdown voltages lower than the supplied voltages of +/-20V. This over-voltage eventually caused the catastrophic breakdown of one of the diodes.

I don't find any particular reason to have these diodes during the laboratory use of the interface. Therefore, I've removed the TVS diodes and left them unreplaced. The circuit was tested on the bench and returned to the rack. All the cables are hooked up, and now the BRLMs look as usual.


Details

- The board version was found to be D1000749-v2

- There was an obvious sign of burning or thermal history around the components D17 and D14. The solder of the D17 was so brittle that just a finger touch was enough to remove the component.

- These D components are TVS diodes (Transient Voltage Suppression Diodes) manufactured by Littelfuse Inc. It is sort of a surge/overvoltage protector to protect rest of the circuit to be exposed to excess voltage. The specified component for D17/D14 was 5.0SMMDJ20A with reverse standoff voltage (~operating voltage) of 20V and the breakdown voltage of 22.20V(min)~24.50V(max). However, the spec sheet told that the marking of the proper component must be "5BEW" rather than "DEM," which is visible on the component. Some search revealed that the used component was SMDJ15A, which has the breakdown voltage of 16.70V~18.50V. This spec is way too low compared to the supplied voltage of +/-20V.

Attachment 1: P_20180730_173134.jpg
P_20180730_173134.jpg
Attachment 2: P_20180730_180151.jpg
P_20180730_180151.jpg
  14119   Tue Jul 31 08:17:55 2018 SteveUpdateSUSTrillium interface box was fixed,reinstalled & working

 

 

Attachment 1: all_OK.png
all_OK.png
  13482   Fri Dec 15 17:05:55 2017 gautamUpdatePEMTrillium seismometer DC offset

Yesterday, while we were bringing the CDS system back online, we noticed that the control room wall StripTool traces for the seismic BLRMS signals did not come back to the levels we are used to seeing even after restarting the PEM model. There are no red lights on the CDS overview screen indicative of DAQ problems. Trending the DQ-ed seismometer signals (these are the calibrated (?) seismometer signals, not the BLRMS) over the last 30 days, it looks like

  1. On ~1st December, the signals all went to 0 - this is consistent with signals in the other models, I think this is when the DAQ processes crashed.
  2. On ~8 December, all the signals picked up a DC offset of a few 100s (counts? or um/s? this number is after a cts2vel calibration filter). I couldn't find anything in the elog on 8 December that may be related to this problem.

I poked around at the electronics rack (1X5/1X6) which houses the 1U interface box for these signals - on its front panel, there is a switch that has selectable positions "UVW" and "XYZ". It is currently set to the latter. I am assuming the former refers to velocities in the xyz directions, and the latter is displacement in these directions. Is this the nominal state? I didn't spend too much time debugging the signal further for now.

 

Attachment 1: Trillium.png
Trillium.png
  13483   Fri Dec 15 18:23:03 2017 ranaUpdatePEMTrillium seismometer DC offset

UVW refers to the 3 internal, orthogonal velocity sensors which are not aligned with the vertical or horizontal directions. XYZ refers to the linear combinations of UVW which correspond to north, east, and up.

  8466   Fri Apr 19 15:19:25 2013 JamieUpdatePEMTrilliums moved from bench to concrete

I moved the two Trillium seismometers that Den left on the electronics bench out onto the new concrete blocks in the lab that will be their final resting places.  I moved one onto the slab at the vertex and the other to the slab at the Y end.  I left them both locked and just sitting on the concrete.

The pile of readout electronics that were sitting next to them I moved on to the yellow foam box half way down the MC tube, between the MC tube and the X arm tube.  This is obviously not a good place to store them, but I couldn't think of a better place to put them for the moment.

  11532   Thu Aug 27 01:41:41 2015 IgnacioUpdateIOOTriply Improved SISO (T240-X) FF of MCL

Earlier today I constructed yet another SISO filter for MCL. The one thing that stands out about this filter is its strong roll off wink. This prevents high frequency noise injection into YARM. The caviat, filter performance suffered broken heart quite a bit, but there is subtraction going on.

I have realized that Vectfit lacks the ability of constraining the fits it produces, (AC coupling, rolloff, etc) even with very nitpicky weighting. So the way I used vectfit to produce this filter will be explained in a future eLOG, I think it might be promising. 

Anyways, the usual plots are shown below. 

 

Filter:

T240-X (SISO)

 

 

Training data + Predicted FIR and IIR subtraction:

 

Online subtraction results:(High freq. stuff shown for noise injection evaluation of the filter)

MCL
 
YARM
 
 
 

Subtraction performace:

 

  15698   Thu Dec 3 10:33:00 2020 gautamUpdateVACTrippLite UPS delivered

The latest greatest UPS has been delivered. I will move it to near the vacuum rack in its packaging for storage. It weighs >100lbs so care will have to be taken when installing - can the rack even support this?

Attachment 1: DFDD4F39-3F8A-439D-888D-7C0CE2E030CF.jpeg
DFDD4F39-3F8A-439D-888D-7C0CE2E030CF.jpeg
  7123   Wed Aug 8 20:34:29 2012 JenneUpdateASSTrouble measuring sensing matrix

I turned on the ASS, without closing the loops, to try to measure the sensing matrix. 

The Yarm was locked (Eric did a nice job earlier - he'll ELOG ABOUT IT before he goes home!), and I used an LO CLKGAIN of 300 on all of the TRY Lockins.  Then I put on and took away a 10% offset in pitch, but it's almost impossible to see the difference. 

The attached is a truly awful screenshot, but you can kind of see what's going on.  The big steps are me increasing the LO gain, but around "0" on the x-axis I changed the pitch offset from 10% away to nominal.  Since there are such big oscillations, the change is basically non-existent.  Grrrr. I'll look at it again tomorrow, since I have an exiting bike ride home ahead of me....

 

  7124   Wed Aug 8 20:50:39 2012 KojiUpdateASSTrouble measuring sensing matrix

From the log, I couldn't understand what has been done.

The procedure we should perform is

  1. Dither total 4 dofs of the two mirrors with different frequencies. Some fluctuation of TRY is even visible in dataviewer.
  2. The cavity is aligned at the beginning. These 4 peaks in TRY in DTT is small or invisible. Some 2nd harmonics are visible.
  3. Misalign one of the dofs. Some peaks get bigger.
  4. Correspoding lockin output becomes bigger.

Then you can start measuring the sensing matrix. At which part did the attempt fail?

Quote:

I turned on the ASS, without closing the loops, to try to measure the sensing matrix. 

The Yarm was locked (Eric did a nice job earlier - he'll ELOG ABOUT IT before he goes home!), and I used an LO CLKGAIN of 300 on all of the TRY Lockins.  Then I put on and took away a 10% offset in pitch, but it's almost impossible to see the difference. 

The attached is a truly awful screenshot, but you can kind of see what's going on.  The big steps are me increasing the LO gain, but around "0" on the x-axis I changed the pitch offset from 10% away to nominal.  Since there are such big oscillations, the change is basically non-existent.  Grrrr. I'll look at it again tomorrow, since I have an exiting bike ride home ahead of me....

 

  7129   Thu Aug 9 00:23:11 2012 JenneUpdateASSTrouble measuring sensing matrix

Quote:

From the log, I couldn't understand what has been done.

The procedure we should perform is

  1. Dither total 4 dofs of the two mirrors with different frequencies. Some fluctuation of TRY is even visible in dataviewer.
  2. The cavity is aligned at the beginning. These 4 peaks in TRY in DTT is small or invisible. Some 2nd harmonics are visible.
  3. Misalign one of the dofs. Some peaks get bigger.
  4. Correspoding lockin output becomes bigger.

Then you can start measuring the sensing matrix. At which part did the attempt fail?

Quote:
 

 Cavity started out aligned pretty well, but not 100%.  Transmission was ~0.8 . Perhaps this was part of the problem.

I realize now that you mention it, it was totally amateur hour of me to only look at the lockin outputs on StripTool (plus POY and TRY on Dataviewer), and not look at TRY on DTT...or any spectra at all.  Not so intelligent.  I could see some fluctuation of TRY on Dataviewer that corresponded to me turning on the oscillators, as well as the spot wiggling on the camera view of ETMYT a teeny bit.

When applying a 10% misalignment to ETMY Pit (by adding 0.1 to the Pit components of the output matrix, as is done in the MC spot position calibration), I could see that there was a small jump in the StripTool trace, but it was much smaller than the ambient fluctuations of the output. 

I just looked back and realized that I must have forgotten to add my screenshot, but it's saved on a desktop on Rossa.  It would be better if I had attached the data, but from that you see that the average of the lockin output signal didn't change very much in the last several minutes of the measurement, but the fluctuations (no misalignment offsets) are pretty big, maybe ~10% or 15% the size of the signal.  Then when I added the misalignment to one mirror (ETMY PIT), there is a very small jump in the lockin signal, but it is much, much smaller than the size of the ambient fluctuations.  Perhaps a long average would result in a "real" value, but by looking by eye, I can't see a discernible difference in the average value of the lockin outputs.

My plan is to do as you say, dithering all 4 optics, and misaligning a single optic's single DoF (Pit or Yaw), and seeing how that misalignment affected each of the sensors (the lockin outputs).  Then put that DoF back to nominal, and misalign a different DoF, rinse and repeat.

Okay, so this is a little stream-of-consciousness-y, and you're going to think I'm really dumb, but I just realized that I haven't set the phase of the lockin demodulators yet.  So I think I need to dither the optics, and go through each of the sensors, and adjust the phase until the peak in TRY in DTT is maximized for the I phase, and minimized for the Q phase (since we use the I-output).  Bah.  Bad Jenne.

  7131   Thu Aug 9 01:26:03 2012 KojiUpdateASSTrouble measuring sensing matrix

That's a good point, but I suspect that you end up with the in-phase (0deg) as the response of the IFO is immediate compared with the dithering frequency
as long as the whitening/dewhitening are properly compensated in the digital realm.

Quote:

 Okay, so this is a little stream-of-consciousness-y, and you're going to think I'm really dumb, but I just realized that I haven't set the phase of the lockin demodulators yet.  So I think I need to dither the optics, and go through each of the sensors, and adjust the phase until the peak in TRY in DTT is maximized for the I phase, and minimized for the Q phase (since we use the I-output).  Bah.  Bad Jenne.

 

  11251   Sun Apr 26 00:08:56 2015 ranaHowToelogTroubles with putting plots in external locations

If it all possible, don't use links to your home directory. Its not robust. It would be like if you clicked on your Google Music and it told you to ask me to sing that song to you. Imagine that on auto-repeat next time your fancy-bone itches.

Attachment 1: 48.png
48.png
  6383   Wed Mar 7 23:28:41 2012 Lab Cleanup CrewHowToEnvironmentTrue Beauty....

Or, how a lab should look at the end of every day.

Clean_40m_Electronics_Bench.jpg

Beat that, Bridge kids!

  15943   Fri Mar 19 10:49:44 2021 Paco, AnchalUpdateSUSTrying coil actuation balance

[Paco, Anchal]

  • We decided to try out the coil actuation balancing after seeing some posts from Gautum about the same on PRM and ETMY.
  • We used diaggui to send swept sine excitation signal to C1:SUS-MC3_ULCOIL_EXC and read it back at C1:SUS-MC3_ASCPIT_IN1. Idea was to create transfer function measurements similar to 15880.
  • We first tried taking the transfer function with excitation amplitude 0f 1, 10, 50, 200 with damping loops on (swept from 10 to 100 Hz lograthmically in 20 points).
  • We found no meaningful measurement and looked like we were just measuring noise.
  • We concluded that it is probably because our damping loops are damping all the excitation down.
  • So we decided to switch off damping and retry.
  • We switched off: C1:SUS-MC3_SUSPOS_SW2 , C1:SUS-MC3_SUSPIT_SW2, C1:SUS-MC3_ASCPIT_SW2, C1:SUS-MC3_ASCYAW_SW2, C1:SUS-MC3_SUSYAW_SW2, and C1:SUS-MC3_SUSSIDE_SW2.
  • We repeated teh above measurements going up in amplitudes of excitation as 1, 10, 20. We saw the oscillation going out of UL_COIL but the swept sine couldn't measure any meaningful transfer function to C1:SUS-MC3_ASCPIT_IN1. So we decided to just stop. We are probably doing something wrong.

Trying to go back to same state:

  • We switch on: C1:SUS-MC3_SUSPOS_SW2 , C1:SUS-MC3_SUSPIT_SW2, C1:SUS-MC3_ASCPIT_SW2, C1:SUS-MC3_ASCYAW_SW2, C1:SUS-MC3_SUSYAW_SW2, and C1:SUS-MC3_SUSSIDE_SW2.
  • But C1:SUS-MC3_ASCYAW_INMON had accumulated about 600 offset and was distrupting the alignment. We switched off C1:SUS-MC3_ASCYAW_SW2 hoping the offset will go away once the optic is just damped with OSEM sensors, but it didn't.
  • Even after minutes, the offset in C1:SUS-MC3_ASCYAW_INMON kept on increasing and crossed beyond 2000 counts limit set in C1:IOO-MC3_YAW filter bank.
  • We tried to unlock the IMC and lock it back again but the offset still persisted.
  • We tried to add bias in YAW DOF by increasing C1:SUS-MC3_YAW_OFFSET, and while it was able to somewhat reduce the WFS C1:SUS-MC3_ASCYAW_INMON offset  but it was misalgning the optic and the lock was lost. So we retracted the bias to 0 and made it zero.
  • We tried to track back where the offset is coming from. In C1IOO_WFS_MASTER.adl, we opened the WFS2_YAW filter bank to see if the sensor is indeed reading the increasing offset.
  • It is quite weird that C1:IOO-WFS2_YAW_INMON is just oscillating but the output in this WFS2_YAW filter bank is slowly increasing offset.
  • We tried to zero the gain and back to 0.1 to see if some holding function is causing it, but that was not the case. The output went back to high negative offset and kept increasing.
  • We don't know what else to do. Only this one WFS YAW output is increasing, everything else is at normal level with no increasing offset or peculiar behavior.
  • We are leaving C1:SUS-MC3_ASCYAW_SW2 off as it is disrupting the IMC lock.

[Jon walked in, asked him for help]

  • Jon suggested to do burt restore on IOO channels.
  • We used (selected through burtgooey):
    burtwb -f /opt/rtcds/caltech/c1/burt/autoburt/snapshots/2021/Mar/19/08:19/c1iooepics.snap -l /tmp/controls_1210319_113410_0.write.log -o /tmp/controls_1210319_113410_0.nowrite.snap -v <
  • No luck, the problem persists.
  15951   Mon Mar 22 11:57:21 2021 Paco, AnchalUpdateSUSTrying coil actuation balance

[Paco, Anchal]

  • For MC coil balancing we will use the ASC (i.e. WFS) error signals since there are no OPLEV inputs (are there OPLEVs at all?).

Test MC1

  • Using the SUS screen LockIns the plan is to feed excitation(s) through the coil outputs, and look at the ASC(Y/P) error signals.
  • A diaggui xml template was saved in /users/Templates/SUS/MC1-actDiag.xml which was based on /users/Templates/SUS/ETMY-actDiag.xml
  • Before running the measurement, we of course want to plug our input matrix, so we ran /scripts/SUS/InMatCalc/writeMatrix.py only to find that it tripped the MC1 Watchdog.
    • The SIDE input seems to have the largest rail, but we just followed the procedure of temporarily increasing the WD max! threshold to allow the damping action and then restoring it.
    • This happened because in latest iteration of our code, we followed an advice from the matlab code to ensure the SIDE OSEM -> SIDE DOF matrix element remains positive, but we found out that MC1 SIDE gain (C1:SUS-MC1_SUSSIDE_GAIN) was set to -8000 (instead of a positive value like all other suspensions).
    • So we decided to try our new input matrix with a positive gain value of 8000 at C1:SUS-MC1_SUSSIDE_GAIN and we were able to stablize the optic and acquire lock, but...
    • We saw that WFS YAW dof started accumulating offset and started disturbing the lock (much like last friday). We disabled the ASC Input button (C1:SUS-MC1_ASCYAW_SW2).
    • This made the lock stable and IMC autolocker was able to lock. But the offset kept on increasing (see attachment 1).
    • After sometime, the offset begain to exponential go to some steady state value which was around -3000.
  • We wrote back the old matrix values and changed the C1:SUS-MC1_SUSSIDE_GAIN back to -8000. But the ASCYAW offset remained to the same position. We're leaving it disabled again as we don't know how to fix this. Hopefully, it will organically come back to small value later in the day like last time (Gautum just reenabled the ASCYAW input and it worked).

Test MC3

  • Defeated by MC1, we moved to MC3.
  • Here, the gain value for C1:SUS-MC3_SUSSIDE_GAIN was already positive (+500) so it could directly take our new matrix.
  • When we switched off watchdog, loaded the new matrix and switched the watchdog back on.
  • The IMC lock was slightly distrupted but remain locked. There was no unusual activity in the WFS sensor values. However, we saw the the SIDE coil output is slowly accumulating offset.
  • So we switched off the watchdog before it will trip itself, wrote back the old matrix and reinstated the status quo.
  • This suggests we need to carefully look back our latest changes of normalization and have new input matriced which keep the system stable other than working on paper with offline data.
Attachment 1: 210322_MC1_ASCY.pdf
210322_MC1_ASCY.pdf
Attachment 2: NewandOldMatrices.tar.gz
  15952   Mon Mar 22 15:10:00 2021 ranaUpdateSUSTrying coil actuation balance

There's an integrator in the MC WFS servos, so you should never be disabling the ASC inputs in the suspensions. Disabling 1 leg in a 6 DOF MIMO system is like a kitchen table with 1 leg removedcheeky.

Just diagnose your suspension stuff with the cavity unlocked. You should be able to see the effect by characterizing the damping loops / cross-coupling.

  15954   Mon Mar 22 19:07:50 2021 Paco, AnchalUpdateSUSTrying coil actuation balance

We found that following protocol works for changing the input matrices to new matrices:

  • Shut the PSL shutter C1:PSL-PSL_ShutterRqst. Switch off IMC autolocker C1:IOO-MC_LOCK_ENABLE.
  • Switch of the watchdog, C1:SUS-MC1_LATCH_OFF.
  • Update the new matrix. (in case of MC1, we need to change sign of C1:SUS-MC1_SUSSIDE_GAIN for new matrix)
  • Switch on the watchdog back again which enables all the coil outputs. Confirm that the optic is damped with just OSEM sensors.
  • Switch on IMC autolocker C1:IOO-MC_LOCK_ENABLE and open PSL shutter C1:PSL-PSL_ShutterRqst.

We repeated this for MC2 as well and were able to lock. However, we could not do the same for MC3. It was getting unstable as soon as cavity was locked i.e. the WFS were making the lock unstable. However, the unstability was different in different attempts but we didn't try mroe times as we had to go.


Coil actuation balancing:

  • We set LOCKIN1 and LOCKIN2 oscillators at 10.5 Hz anf 13.5 Hz with amplitude of 10 counts.
  • We wrote PIT, YAW and Butterfly actuation vectors (see attached text files used for this) on LOCKIN1 and LOCKIN2 for MC1.
  • We measured C1:SUS-MC1_ASCYAW_IN1 and C1:SUS-MC1_ASCPIT_IN1 and compared it against the case when no excitation was fed.
  • We repeated the above steps for MC2 except that we did not use LOCKIN2. LOCKIN2 was found to already on at oscillator frequency of 0.03Hz with amplitude of 500 counts and was fed to all coils with gain of 1 (so it was effectively moving position DOF at 0.03 Hz.) When we changed it, it became ON back again after we turned on the autolocker, so we guess this must be due to some background script and msut be important so we did not make any changes here. But what is it for?
  • We have gotten some good data for MC1 and MC2 to ponder upon next.
  • MC1 showed no cross coupling at all while MC2 shoed significant cross coupling between PIT and YAW.
  • Both MC1 and MC2 did not show any cross coupling between butterfly actuation and PIT/YAW dof.

On another news, IOO channels died!

  • Infront of us, the medm channels starting with C1:IOO just died. See attachment 8.
  • We are not sure why that happened, but we have reported everything we did up here.
  • This happened around the time we were ready to switch back on the IMC autolocker and open the shutter. But now these channels are dead.
  • All optics were restored with old matrices and settings and are damped in good condition as of now.
  • IMC should lock back as soon as someone can restart the EPICS channels and switch on C1:IOO-MC_LOCK_ENABLE and C1:PSL-PSL_ShutterRqst.
Attachment 1: 20210322_MC1_CoilBalancePIT.pdf
20210322_MC1_CoilBalancePIT.pdf
Attachment 2: 20210322_MC1_CoilBalanceYAW.pdf
20210322_MC1_CoilBalanceYAW.pdf
Attachment 3: 20210322_MC1_CoilBalanceBUTT.pdf
20210322_MC1_CoilBalanceBUTT.pdf
Attachment 4: 20210322_MC2_CoilBalancePIT.pdf
20210322_MC2_CoilBalancePIT.pdf
Attachment 5: 20210322_MC2_CoilBalanceYAW.pdf
20210322_MC2_CoilBalanceYAW.pdf
Attachment 6: 20210322_MC2_CoilBalanceBUTT.pdf
20210322_MC2_CoilBalanceBUTT.pdf
Attachment 7: 20210322_IMC_CoilBalance.tar.gz
Attachment 8: image-e6019a14-9cf3-45f7-8f2c-cc3d7ad1c452.jpg
image-e6019a14-9cf3-45f7-8f2c-cc3d7ad1c452.jpg
  3467   Wed Aug 25 12:18:47 2010 josephbUpdateelogTrying new version of elog to see if it helps stability

So unfortunately, I made the start-elog-nodus script smart enough to kill the debugging run I had (although thats probably good since there might have been issues with continuing to run - just poor timing on part of the crash).

In related news, I have gotten the latest version of the elog code to actually compile on Nodus.  I had to hack the cryptic.c file (elog/src/cryptic.c) to get it to work though.

The following was copied from the #ifdef _MSC_VER section of the code into the #else directly following that section. 

#define MAX(x,y) ((x)>(y)?(x):(y))
#define MIN(x,y) ((x)<(y)?(x):(y))
#define __alignof__(x) sizeof(x)
#define alloca(x) malloc(x)
#define mempcpy(d, s, n) ((char *)memcpy(d,s,n)+n)
#define ERANGE 34


I also removed #include <stdint.h> as the functionality it provides is covered by inttypes.h on Solaris machines, which is automatically included.

This new code was released August 5th 2010, while the old elog code we were running was 2.7.5 and was released sometime in 2008.  There are several crash fixes mentioned in the version notes so I'm hoping this may improve stability. I'm in the process of making a copy of the elog logbooks into the elog-2.8.0 install (so as to have a backup with the original 2.7.5).  I'm also copying over all the configuration files.   In a few minutes I'm going to try switching over to the new elog.  If it doesn't work, or is worse, its easy enough to just start up the current version.

All files are located in /cvs/cds/caltech/elog/elog-2.8.0 (the old directory is elog-2.7.5).  I've made  a new startup script called start-elog-nodus-2.8.0.  To start the new one, just run that script.  To start the old one, just go to the elog-2.7.5 directory and run the old start-elog-nodus script.

  10641   Mon Oct 27 19:15:54 2014 ericqUpdateLSCTrying to PRMI on 165

I spent some time trying to debug our inability to get MICH onto REFL165Q while the arms are held off with ALS, to no real success. 

I set up our usual repeatable situation of PRMI on 33 I&Q, arms held off with ALS. I figured that it may help to first sideband lock on REFL55, since 165 is looking for the f2 sidebands and maybe there is some odd offset between the locking points for f1 and f2 or other weirdness. 


REFL 55 settings:

Demod angle 98->126 (was previously set for PRY locking)

PRCL = 0.5 * REFL55 I (UGF of ~200 Hz) (FM gain unchanged from REFL33 situation of -0.02)

MICH = 0.125 * REFL55 Q (UGF of ~60Hz) (same FM gain as 33)

Some REFL55 offset adjusting had to be done in order to not disturb the 33-initiated lock when handing off. 

I also adjusted POP110 phase to zero the Q when locked, and switched the triggering over to 110I


The PRMI can acquire lock like this with arms held off with ALS, no problem. 

Here, I tried to hop over to 165. PRCL was no problem, needing a +1 on 165I. However, I had no success in handing off MICH.   I twiddled many knobs, but none that provably helped. 

I saw indications that the sensing angle in 165 is small (~20deg), which is not consistent with current knowledge of the cavity lengths. We last interferometrically measured the PRC length by letting the PRMI swing and looking at sideband splitting in POP110. At LLO, they did a length measurement by looking at demod angle differences in PRMI carrier vs. sideband locking. (alog8562) This might be worth checking out...

  10649   Wed Oct 29 03:33:38 2014 ericqUpdateLSCTrying to PRMI on 165

 

Short report: Further frustrated by 165 tonight. The weird thing is, the procedure I'm trying with the arms held off on ALS (i.e. excitation line in MICH and PRCL, adjust relative gains to make the signs and magnitudes mach, ezcastep over) works flawlessly with the ETMs misaligned. One can even acquire SB PRMI lock on 165 I&Q, with 80-90 degrees of demod angle between MICH and PRCL. The only real difference in REFL55 settings for misaligned vs. ALS-offset arms is an extra factor of two in the FM gains to maintain the same UGF, so I hoped that the matrix elements for 165 with misaligned arms would hold for ALS-offset arms. 

Alas, no such fortune. I still have no clear explanation for why we can't get MICH on 165Q with the arms held off on ALS. 

I also gave a quick try to measuring the PRCL->REFL55 demod phase difference between carrier and sideband lock (with arms misaligned), and got something on the order of 55 degrees, which really just makes me think I wasn't well set up / aligned, rather than actually conveying information about the PRC length...

  13227   Thu Aug 17 22:54:49 2017 ericqUpdateComputersTrying to access JetStor RAID files

The JetStor RAID unit that we had been using for frame writing before the fb meltdown has some archived frames from DRFPMI locks that I want to get at. I spent some time today trying to mount it on optimus with no success crying

The unit was connected to fb via a SCSI cable to a SCSI-to-PCI card inside of fb. I moved the card to optimus, and attached the cable. However, no mountable device corresponding to the RAID seems to show up anywhere.

The RAID unit can tell that it's hooked up to a computer, because when optimus restarts, the RAID event log says "Host Channel 0 - SCSI Bus Reset."

The computer is able to get some sort of signals from the RAID unit, because when I change the SCSI ID, the syslog will say 'detected non-optimal RAID status'.

The PCI card is ID'd fine in lspci as "06:01.0 SCSI storage controller: LSI Logic / Symbios Logic 53c1030 PCI-X Fusion-MPT Dual Ultra320 SCSI (rev c1)"

'lsssci' does not list anything related to the unit

Using 'mpt-status -p', which is somehow associated with this kind of thing returns the disheartening output:

Checking for SCSI ID:0
Checking for SCSI ID:1
Checking for SCSI ID:2
Checking for SCSI ID:3
Checking for SCSI ID:4
Checking for SCSI ID:5
Checking for SCSI ID:6
Checking for SCSI ID:7
Checking for SCSI ID:8
Checking for SCSI ID:9
Checking for SCSI ID:10
Checking for SCSI ID:11
Checking for SCSI ID:12
Checking for SCSI ID:13
Checking for SCSI ID:14
Checking for SCSI ID:15
Nothing found, contact the author
 
I don't know what to try at this point.
  3644   Mon Oct 4 15:28:10 2010 josephbUpdateCDSTrying to get c1ioo booting as Gentoo.

I modified the dhcpd.conf file in /etc/dhcp on the fb machine.  I added a entry for c1ioo, listing its MAC address and ip number near the bottom of the file.  I then restarted the dhcp server using "sudo /etc/init.d/dhcpd restart" while on the fb machine.

I also modified the rtsystab, which is used to determine which front end codes start on boot up of a machine.  I added a line: c1ioo   c1x03  c1ioo

I am now in the process of getting c1ioo to come up as a Gentoo machine so I can build a model with an RFM connection in it and test the communication between c1sus and c1ioo.  This involves removing the hard drives and checking to make sure the boot priority is correct (i.e. it checks for a network boot).

  2927   Thu May 13 15:19:44 2010 josephbUpdateCDSTrying to get lsc.mdl and lsp.mdl working

I had a chat with Alex this morning and discovered that the dcu_ids 13,14,15,16 are reserved currently, and should not be used.  I was told 9-12 and 17-26 were fine to use.  I pointed out that we will eventually have more modules than that.  His response was he is currently working on the framebuilder code and "modernizing" it, and that those restrictions will hopefully be lifted in the future although he isn't certain at this time what the real maximum gds_id number is (he was only willing to vouch for up to 26 - although the OMC seems to be currently working and set to 30).

Alex also suggested running an iop module to provide timing (since we are using adcSlave=1 option in the models).  Apparently these are x00.mdl, x01.mdl, x11.mdl files in the /home/control/cds/advLigoRTS/src/epics/simLink/ directory.  I saved x00.mdl as io1.mdl (I didn't want to use io0 as its a pain to differentiate between a zero and 'O'.  This new IOP is using gds_node=1, dcu_id=9.  I modified the approriate files to include it.

I modified /etc/rc.d/rc.local and added io1 to shmem line.  I modified /cvs/cds/caltech/target/fb/daqdrc to use dcu_id 9 as the controller (this is the new iop model dcu_id number).  In that same directory I modifed the file master by adding /cvs/cds/caltech/chans/daq/C1IO1.ini as well as uncommenting tpchn_C1 line.  I modified testpoint.par in /cvs/cds/caltech/target/gds/param to include C-node0, and modified the prognum for lsc and lsp to 0x31001003 and 0x31001005.

So I started the 3 processes with startio1, startlsc, startlsp, then went to the fb directory and started the framebuilder.  However, the model lsc.mdl is still having issues, although lsp and io1 seem to be working.  At this point I just need to track down what fundamentally is different between lsc and lsp and correct it in the lsc model.  I'm hoping its not related to the fact that we actually had a previous lsc front end and there's some legacy stuff getting in the way.  One thing I can test is changing the name and see if that runs.

 

  2299   Thu Nov 19 09:55:41 2009 josephbUpdateComputersTrying to get testpoints on megatron

This is a continuation from last night, where Peter, Koji, and I were trying to get test point channels working on megatron and with the TST module.

Things we noticed last night:

We could run starttst, and ./daqd -c daqdrc, which allowed us to get some channels in dataviewer.  The default 1k channel selection works, but none of the testpoints do. 

However, awgtpman -s tst does appear in the processes running list.

The error we get from dataviewer is:

Server error 861: unable to create thread
Server error 23328: unknown error
datasrv: DataWriteRealtime failed: daq_send: Illegal seek

Going to DTT, it starts with no errors in this configuration.  Initially it listed both MDC and TST channels.  However, as a test, I moved the tpchn_C4.par , tpchn_M4.par and tpchn_M5.par files to the directory backup, in /cvs/cds/caltech/target/gds/param.  This caused only the TST channels to show up (which is what we want when not running the mdc module.

We had changed the daqdrc file in /cvs/cds/caltech/target/fb, several times to get to this state.  According to the directions in the RCG manual written by Rolf, we're supposed to "set cit_40m=1" in the daqdrc file, but it was commented out.  However, when we uncommented it, it started causing errors on dtt startup, so we put it back.  We also tried adding lines:

set dcu_rate 13 = 16384;
set dcu_rate 14 = 16384;

But this didn't seem to help.  The reason we did this is we noticed dcuid = 13 and dcuid = 14 in the /cvs/cds/caltech/target/gds/param/tpchn_C1.par file.  We also edited the testpoint.par file so that it correctly corresponded to the tst module, and not the mdc and mdp modules.  We basically set:

[C-node1]
hostname=192.168.1.2
system=tst

in that file, and commented everything else out.

At this point, given all the things we've changed, I'm going to try a rebuild of the tst and daq and see if that solves things.

 

  3507   Wed Sep 1 12:24:47 2010 josephbUpdateCDSTrying to get up to date CDS code runnning

Alex, Joe:

We copied the latest x02 to c1x02 and modified to our the config block in it.

We removed gds_node_id.  We just have one number now, the dcuid, which is unique for each controller, simulated plant and IOP.  Set site to C1 and host to c1sus.

Alex made the latest awgtpman backwards compatible, and checked that into svn.

We installed the latest framecpp onto c1sus from www.ldas-sc.ligo.caltech.edu/packages/ using wget.

wget www.ldas-sc.ligo.caltech.edu/packages/framecpp-1.18 and then used make.

This let us compile diagd on c1sus, using the command make stand in the /advLigoRTS/build area.

We copied gds from the seiteststand over at handford and are trying to build that on megatron.  However, there's a bunch of packages we need for it to install properly.  Alex said he'd work on that later, possibly trying to make some portable binaries.

Checked out the latest dataviewer into /opt/rtcds/caltech/c1/core/daq, however its not quite working yet either.  This is another thing Alex said he'll work on later.

We are also going to test Alex and Rolf's kernel patch over on c1iscex on Centos base kernel (apparently they've been using Gentoo up at hanford for the test stands...) and see how that works.

  16005   Wed Apr 7 17:38:51 2021 AnchalUpdateSUSTrying to uncouple only PIT and YAW first

To test if our method is working at all, we went for the simpler case of just uncoupling PIT and YAW. This is also because the sensor used for these two degrees of freedom is similar (the MC Trans WFS).

We saw a successful decrease in cross-coupling between PIT and YAW over the first 50 iterations that we tried. Here are some results:


Final output matrix:

Output matrix for uncoupling PIT and YAW from eachother
PIT YAW COILS
1.01858 1.16820 UL
0.98107 -0.79706 UR
-0.98107 0.79706 LL
-1.01858 -1.16820 LR

Plots:

  • Attachment 1 shows distance of sensing matrix from identity as iterations go.
  • Attachment 2 shows the off-diagonal elements of sensing matrix as the iterations increase.
    • It is worth noting that PIT -> YAW coupling was the main element that was reduced successfully while the YAW -> PIT was reducing but much more slowly.
    • Most of the remaining cross coupling in the end was from YAW -> PIT.
  • Attachment 3 shows first 10 oscillations in the time series data during excitation of some of the iterations.
  • Attachment 4 shows the cross spectral density of the sensed data during excitation with each other. This has been normalized by reference PSD data (taken with no excitation) of the sensed DOFs involved in the CSD calculation.
  • Attachment 5 shows the TF estimate made by normalizing CSD data column wise by the diagonal elements. The excitation frequency point in these plots become the Sensing matrix in the calculation.
    • One can notice how the PIT -> YAW element is going down in these plots.
    • Even though we are using only the real value of the sensing matrix, the imaginary values are also going down.

Next, tried uncoupling POS and PIT:

  • Next, we tried to uncouple POS and PIT. We expect them to be more coupled than with YAW.
  • At the time of writing this post, 15 iterations of this attempt have been completed and it is not looking good sad.
  • The distance of the sensing matrix from identity is growing at an accelerated rate.
  • The POS output matrix column seems to be trying to go towards the negative of PIT output matrix column! Why? We don't know.
  • We have seen in the past that once POS transforms into PIT or YAW, it just makes the output matrix worse as no feedback actually goes into the POS column. Eventually, the IMC will cease to remain locked.
  • So, I'm cancelling this attempt for now. Will consider more alternatives later.
Attachment 1: SDistanceFromIdentity.pdf
SDistanceFromIdentity.pdf
Attachment 2: SmatIterations.pdf
SmatIterations.pdf
Attachment 3: TimeSeriesPlots.pdf
TimeSeriesPlots.pdf TimeSeriesPlots.pdf TimeSeriesPlots.pdf TimeSeriesPlots.pdf TimeSeriesPlots.pdf TimeSeriesPlots.pdf TimeSeriesPlots.pdf TimeSeriesPlots.pdf
Attachment 4: CSDPlots.pdf
CSDPlots.pdf CSDPlots.pdf CSDPlots.pdf CSDPlots.pdf CSDPlots.pdf CSDPlots.pdf CSDPlots.pdf CSDPlots.pdf
Attachment 5: SmatrixPlots.pdf
SmatrixPlots.pdf SmatrixPlots.pdf SmatrixPlots.pdf SmatrixPlots.pdf SmatrixPlots.pdf SmatrixPlots.pdf SmatrixPlots.pdf SmatrixPlots.pdf
  1426   Wed Mar 25 04:18:28 2009 YoichiUpdateLockingTuesday Locking
After the new PO_DC PD was installed, I tweaked several gains to make the locking scripts work right.
First of all, I increased the gain of PD12 (PD12_I is SPOB) by a factor of 1.4 to compensate for the power decrease
by the insertion of the BS. SPOB is used by the PRM alignment script. I was too lazy to modify the scripts.

Then I optimized the SRC DD signal which is taken from the POB.

I also had to do some gain adjustments for the CARM loop.

The attachment (AO path open loop TF) shows a depressing fact that the 3.8kHz peak is still there with the new PO_DC PD. So it was not a problem of the SPOB PD.
Next, I will check the cross over frequencies of the PZT and PC paths in the FSS and the VCO/MCL cross over.
Attachment 1: AO-Loop-p9.png
AO-Loop-p9.png
  568   Wed Jun 25 13:56:56 2008 JohnSummaryLockingTuesday night locking
Rob, John

Worked to try and reduce the CARM offset using the dc arm transmissions before changing to SPOB DC. This proved somewhat unsuccessful, the offset couldn't be reduced to more than five (arms storing 5x more power than single arm cavity lock).
  16091   Wed Apr 28 17:09:11 2021 AnchalUpdateSUSTuned Suspension Parameters uploaded for long term behavior monitoring

I have uploaded all the new settings mentioned in 16066 and 16072. The settings were uploaded through a single script present at anchal/20210428_IMC_Tuned_Suspension/uploadNewConfigIMC.py. The settings can be reverted back to old settings through anchal/20210428_IMC_Tuned_Suspension/restoreOldConfigIMC.py. Both these scripts can be run only through python3 in donatella or allegra.


GPSTIME of new settings: 1303690144


New settings include:

  • New input matrices for MC1 and MC2.
  • New Output coil gains for AC balancing on all three optics.
  • Switching ON the FM8 filter modulae (Q=3 F2A filter) in POS column on output matrix of all optics.

We'll wait and watch the performance through summary pages and check back the performance on Monday.

  4713   Fri May 13 17:20:48 2011 Leo SingerConfigurationSUSTuned bounce and roll mode of ETMY suspension

I tuned the bounce and roll mode bandstops for ETMY, although it was difficult for me to tell if there was improvement with the bandstops on relative to the bandstops off because it seemed like the bounce and roll modes were being excited intermittently.  I'll take spectra with the filters both on and off during an evening next week.

  9150   Sun Sep 22 21:03:15 2013 ranaConfigurationSUSTuned bounce and roll mode of ETMY suspension

 Today I noticed that there was a lot of noise at the Bounce and Roll eigenfrequencies for ETMY. I found that the bandstop filter were set at completely the wrong frequencies, so I've remade them.

The filters were last tuned by Leo in May of 2011. Even so, he left the frequencies at the frequencies of the old MOS suspensions which had f_bounce ~ 12 Hz.

 The FOTON plot shows the OLD ones versus the NEW ones. The DTT spectra shows the oplev error signals in the usual state. I have also copied these over to the SUSPOS,PIT,YAW, and SIDE filter banks and turned them all ON.

I also turned OFF and deleted the 3 Hz RG filter that was there. There's no such peak in the error signal and even if one wanted to compensate for the stack mode, it should be a low Q filter, not this monster.

Attachment 1: etmy-error.png
etmy-error.png
Attachment 2: notches.pdf
notches.pdf
  4652   Fri May 6 14:59:36 2011 Leo SingerConfigurationSUSTuning ITMY bandstop

I tuned the ITMY bandstops -- 'before' and 'after' spectra attached.  Note that the after the tuning, the bounce mode at ~16 Hz is about twice as quiet!

 

However, notice that in the 'before' plot the roll mode at about 23.5 Hz did not show up at all, whereas it is quite prominent in the 'after' plot.  I was concerned that this line could have been a result of placing the bandstop there, so I made another plot with the BounceRoll filter turned off.  Sure enough, the 23.5 Hz line is still there.  So I'm not crazy: the roll mode did start acting up at some time between my 'before' and 'after' plot, but not as a result of the tuning.

Attachment 1: itmy-before.pdf
itmy-before.pdf
Attachment 2: itmy-after.pdf
itmy-after.pdf
Attachment 3: itmy-nobounceroll.pdf
itmy-nobounceroll.pdf
  8288   Wed Mar 13 16:25:16 2013 ManasaUpdateIOOTuning MC length/FSR

[Koji, Manasa]

We looked at the MC modulation frequency on the spectrum analyzer and observed beat notes between MC modulation freq (29.5MHz) and modulation frequencies (11.06 MHz and 55.3MHz).

Beat notes were suppressed by changing the carrier frequency from 11.065910 MHz to 11.066147MHz. 

Detailed discussion and data will be posted in the next elog.

  8349   Tue Mar 26 01:40:49 2013 KojiUpdateIOOTuning MC length/FSR

I'm still waiting for the follow-up analysis of the modulation freq tuning.

  8353   Tue Mar 26 15:00:55 2013 ManasaUpdateIOOTuning MC length/FSR

Quote:

[Koji, Manasa]

We looked at the MC modulation frequency on the spectrum analyzer and observed beat notes between MC modulation freq (29.5MHz) and modulation frequencies (11.06 MHz and 55.3MHz).

Beat notes were suppressed by changing the carrier frequency from 11.065910 MHz to 11.066147MHz. 

Detailed discussion and data will be posted in the next elog.

The goal was to tune the carrier modulation frequency, f1 ~ 11.06 MHz to match the FSR  (c/2L) of the MC. (Reference to the technique: R.G.DeVoe et al., PRA 30, 5, Nov 1984)

We looked at the MC_REFL output on the spectrum analyzer. Since the MC FSR was not well matched with the carrier modulation frequency, we observed significant beat notes at the following frequencies (fMC-f1),  (fMC+f1), (fMC-f2) and (fMC+f2); where fMC (the MC modulation frequency) = 29.5MHz, f1(carrier modulation frequency) ~ 11.06MHz and f2 ~ 55.3MHz. The carrier modulation frequency was changed at the frequency generator until these beat notes were suppressed i.e. until the cavity FSR matched the carrier modulation frequency.

The plot below shows the MC spectrum after the beat notes were suppressed.

MC_spectrum.png

Attachment 2: MC_spectrum.zip
  8354   Tue Mar 26 15:43:45 2013 ranaUpdateIOOTuning MC length/FSR

  Please attach the data file of the measurement - its hard to get the real information out of picture. In general, WE should always include the code / explanation of how to reconstruct the plot and get the scientific information out.

  8357   Tue Mar 26 17:27:17 2013 KojiUpdateIOOTuning MC length/FSR

Please add the discussions on the cavity absolute length (and its change, adjustment precision),
identification of the peaks, before/after comparison of the plot, the effect of the MC REFL PD response,
and comparison of the cavity linewidth vs deviation of the 55MHz SBs from the resonance.

  7748   Mon Nov 26 23:45:52 2012 AyakaUpdateIOOTuning MC_L

[Rana, Jamie, Ayaka]

We could not lock the arms with MC_L loop on. Therefore we measured the change in YARM error signal when the MC_L is turned on.

POYerr_MCL.jpg

(data; POYerr_MCF.xml in zip file)

Green line; POY error signal when MCL loop was on and the YARM loop gain (0.5) was so high that the saturated control signal made funny peak around 250 Hz.
Blue line; POY error signal when MCL loop was off and the YARM loop gain was low (0.2).
Pink line; POY error signal when MCL loop was on (the gain was -300) and the YARM loop gain was low (0.2).
Red line; POY error signal when MCL loop was on, another low pass filter (2nd order, cut off frequency of 55Hz) was added to MCL loop and the YARM loop gain was low (0.2).

We also changed the filter trigger in order to lock YARM. The FM7 and 8 trigger was turned off. It means that spectrum above was took with FM2,3,4,5,6,9,10 on. Whitening filters were also on.

MCL control signal makes the arm spectrum bad because the MCL control signal moves MC2 mirror additionally and adds extra frequency noise.
Ideally, error signal should be the same at higher frequencies and go down at the lower frequencies when the MCL loop is on because MCL signal should suppress the seismic noise.

Before we added the LPF, MCF/MCL loop cross over (which was taken with the template /users/Templates/MC/MCL-MCF_xover-2012-8-23.xml) is below;

MCL-MCFxover.jpg

(MCL-MCF_xover.xml in zip file)

After the LPF is added, the cross over has been changed as below;
MCL-MCFxover2.jpg

(MCL-MCF_xover2.xml in zip file)

For now, I will just turn off the MCL loop for the acoustic noise experiments.

Attachment 4: 121126.tar.gz
  4646   Thu May 5 17:19:21 2011 Leo SingerConfigurationSUSTuning notch filters for bounce mode suspensions

I am tuning the notch filters for the bounce modes in the suspensions, starting with the ITMs and ETMs.  I'll do the MCs, the PRMs, and the SRMs next.

 

I noticed that the filter for ITMX (in the file C1SUS.txt, the module ITMX_SUSPOS, the selection BounceRoll) that the filter was composed of two bandstops (and a constant gain).  It looked like this:

 

ellip("BandStop",4,1,40,11.4,12.2)ellip("BandStop",4,1,40,16.7,17.5)gain(1.25872)

 

Valera said that one of these was for the roll mode and the other for the bounce mode.  However, looking at the spectra that Kiwamu and I made this week, I don't perceive a resonance between 11.4 and 12.2 Hz.  So, we're taking a guess that this was for a mode that has moved due to new pendulum designs.  For many of the suspensions, in the free swinging test we noticed a line around 23 Hz; we thought we might as well re-use one of these elliptical filters to avoid exciting this line.  Of course, if this line does *not* result from excitation of an uncontrolled degree of freedom, this will not help and could be detrimental.  When we talk to Valera again, we can review this decision and at that point we might decide just to take out that bandstop.

 

ITMX is done.  I'll continue tomorrow.  I've attached closed-loop spectra for before the tuning (itmx-before.pdf) and after (itmx-after.pdf).

 

(Update: the following day, I took closed loop spectra with (itmx-withbounceroll.pdf) and without (itmx-nobounceroll.pdf) the bandstops.  It looks like the bandstops made the bounce mode slightly worse, but the roll mode slightly better.)

 

 

Attachment 1: itmx-before.pdf
itmx-before.pdf
Attachment 2: itmx-before.pdf
itmx-before.pdf
Attachment 3: itmx-withbounceroll.pdf
itmx-withbounceroll.pdf
Attachment 4: timx-nobounceroll.pdf
timx-nobounceroll.pdf
  7709   Tue Nov 13 22:12:15 2012 JenneUpdateIOOTurn off MCL path before doing MC spot measurement

[Jenne, Den]

We have discovered that the MCL loop squishes the length fluctuations that result from the MC spot measurement angular dither.  This is good, in that the MCL is doing what it ought to do.  However, we need to turn it off before doing a spot measurement.

  7711   Wed Nov 14 09:01:42 2012 Dumb statement catcherUpdateIOOTurn off MCL path before doing MC spot measurement

Quote:

We have discovered that the MCL loop squishes the length fluctuations that result from the MC spot measurement angular dither.  This is good, in that the MCL is doing what it ought to do.  However, we need to turn it off before doing a spot measurement.

 This is totally non-sensical statement, of course.

We might also say that the DARM loop totally squishes the GW signal and so its better not to have any feedback in the interferometer.

  7712   Wed Nov 14 13:58:18 2012 JenneUpdateIOOTurn off MCL path before doing MC spot measurement

Quote:

Quote:

We have discovered that the MCL loop squishes the length fluctuations that result from the MC spot measurement angular dither.  This is good, in that the MCL is doing what it ought to do.  However, we need to turn it off before doing a spot measurement.

 This is totally non-sensical statement, of course.

We might also say that the DARM loop totally squishes the GW signal and so its better not to have any feedback in the interferometer.

 Hmmm, indeed.  To keep MC_L on, we should be looking at the control signal rather than the error signal.  I think Den has MC_L running nicely such that it always comes on when the MC locks, so I can switch it.

  8617   Wed May 22 15:48:56 2013 JamieUpdateSUSTurn off zero padding in DAC outputs

After the results of the analysis in the #8598 thread, I have added the "no_zero_pad=1" flag to the cdsParameters block of all SUS models:

  • c1mcs
  • c1sus
  • c1scx
  • c1scy

The upsampling to the 64 kHz DAC output will now be done with sample-holds, instead of zero-pads.  This should reduce the 32 kHz lines we were noticing in the analog DAC output.

I note, though, that Brian Lantz points out that this might actually introduce a delay of about a half sample.  We will continue to investigate.

In any event, I have rebuilt and installed all models listed above.  I will restart as soon as opportunity allows.

  8625   Thu May 23 10:20:33 2013 JamieUpdateSUSTurn off zero padding in DAC outputs

Quote:

After the results of the analysis in the #8598 thread, I have added the "no_zero_pad=1" flag to the cdsParameters block of all SUS models:

  • c1mcs
  • c1sus
  • c1scx
  • c1scy

The upsampling to the 64 kHz DAC output will now be done with sample-holds, instead of zero-pads.  This should reduce the 32 kHz lines we were noticing in the analog DAC output.

I note, though, that Brian Lantz points out that this might actually introduce a delay of about a half sample.  We will continue to investigate.

In any event, I have rebuilt and installed all models listed above.  I will restart as soon as opportunity allows.

I have restarted all the suspension models with the new no_zero_pad flag for the DAC upsampling.  Everything came up fine and all optics are damped as expected (except for concerns about c1scy which I'll note in a followup).

ELOG V3.1.3-