The Y arm has been locked with AS55.

A next thing is to check the spot positions on the ETMY and ITMY mirrors so that we can evaluate the recent beam pointing.

- - - parameter settings - - -

C1:LSC-YARM_GAIN = -0.03

AS55 demod phase = 0.2

WF gains = 21 dB

C1:LSC-TRY_OUT = 0.57 (maximized by steering PZT2)

The spot positions on ITMY and ETMY were measured using the LOCKIN modules in C1ASS when the Y arm stayed locked.

The beam was successfully aligned such that it hits the center of the ETMY mirror.

However on the other hand the angle of the beam is pitching and it's going upward as the beam propagates to ETMY.

/***** RESULTS ******/

Here is a summary of the measurement :

Also a cartoon is shown below.

The scale is not quite true, but at least it gives you a 3D information of how the beam is pointing down to the Y arm.

  /***** MEASUREMENT *****/

 In order to measure the spot positions the standard technique, namely A2L, was used.

Since the C1ASS model was made for doing the A2L measurements on each arm cavity, the LOCKIN modules in C1ASS were used.

First the Y arm was locked with AS55 (#5398), and then the C1ASS was activated by calling some scripts from C1ASS_QPDs.adl.

In order to calibrate the signals from LOCKINs, an intentional coil imbalance was introduce.

This is the same calibration technique as Valera explained before (#4355) for measurement of the MC spot positions.

Forgot to attach a picture of the ITMY's face camera when it was locked.

The horizontal position of the spot looks good, but the vertical position is apparently too low, which agrees with the A2L result.

Although we did some of the Input Matrix diagonalization, we have not yet actually used this knowledge. As a result all of the optics are shaking all over the place.

Sunshine Task: Set the input matrices to their calculated values and then adjust the OSEM damping gains for all optics so as to get a Q ~ 5.

The f2a filters were newly designed and installed on BS and PRM.

So the lock of PRMI will be more stable .

Once the SRM oplev project settles down, I will adjust the f2a filters on SRM too.

New f2a filters were installed on SRM.

The lock of DRMI should be more stable than last night.

The bad medm screens have been fixed. There are no blank fields and all the links are correct.

With the new input matrix, it looks like YAW and SIDE are not quite decoupled on ETMX.

It needs one more kick and free swinging test.

- - - details

 To see what exactly is going on, I changed the input matrix from the default to the new one, which Jenne computed (#5421) on ETMX.

I started putting the elements of the input matrix from POS through SIDE, one by one.

It seemed that POS and PIT worked fine. However the YAW signal looks containing a lot of the SIDE signal.

Similar to YAW, SIDE also interact with the YAW motion and somehow rings up both YAW and SIDE signals as Jenne reported ( #5438).

So right now the YAW and SIDE rows are partially reburted to the default elements in order to avoid ringing up.

Excited all the optics. They will be automatically back after 5 hours.

Sat Sep 17 02:02:07 PDT 2011
1000285342

The f2a filters were installed on ITMs and ETMX.

Now all of the suspensions has the f2a filters.

[Anamaria / Kiwamu]

 The incident beam pointing was improved by using PZT1 and PZT2. 

With some triggers the lock of PRMI became smoother.

For the DRMI lock, the MICH and SRCL signals on AS55 are not quite decoupled, so we should find cleaner signals for them.

(what we did)

 + locked the Y arm

 + aligned incident beam by using PZT1(#5450) and PZT2. The spot positions on ITMY and ETMY are now well-centered.

 + tried activating C1ASS but failed. It needs some gain changes due to the new PZT1 response.

 + locked the X arm

 + aligned the TRX PD (Thorlab signal PD) and set the trigger.

 + C1ASS also doesn't work for the X arm

 + realigned the PRM and BS oplevs. the PRM oplev was clipped at a steering mirror on the optical bench

 + locked PRMI and aligned the PRM mirror such that the optical gain was maximized

 + optimized the demod phase of AS55 and REFL11

 + checked the UGF of the MICH and PRCL lock. The UGF of MICH is about 100Hz with gain of -20, and the UGF of PRCL was 85 Hz with gain of 0.1

 + adjusted the output matrix such that the MICH control doesn't couple into the PRCL control.

 + set the triggers for the MICH and PRCL control to make the lock acquisition smoother.

 + tried locking DRMI and it was sort of locked. However the SRCL signal showed up a lot in AS55_Q, where the MICH signal is extracted.

Actually the clipping of POP wasn't in the chamber but it was on the first lens on the optical bench.

So I repositioned the lens to avoid the clipping and now there are no clipping on POP.

GOAL1:  Stable lock of DRMI

GOAL2:  Measurement of the LSC input matrix in the DRMI configuration

 /- - Daytime works - - /

  + Measurement of the arm lengths (Jenne / Kiwamu / volunteers)

  + Optimization of the oplev control loops (Paul)

  + Inversion and installation of the SUS input matrices (Jenne)

  + Tuning of the SUS damping gains (Steve)

  + Measurement of the modulation depths (Mirko)

  + Preparation of the green broadband PD (Katrin)

  + Fixing the Y arm green lock servo (Katrin / Kiwamu)

  + Installation of RFPDs (Anamaria)

  + Minimization of the AM sidebands (Anamaria / Keiko)

  + Preparation of a script for measuring the LSC input matrix (Keiko)

  + MC WFS (Suresh)

  + Online adaptive filtering (Mirko / Jenne)

  + Modification of C1ASS (Kiwamu)

  + Fixing IPPOS (volunteers) 

  + Auto alignment of PRCL and SRCL (volunteers)

  + Loss measurement of the arm cavities (volunteers)

  + Fixing the ETMX SIDE slow monitor (volunteers)

 /- - Nighttime works - - /

 + Locking of DRMI

 + Characterization of DRMI and complete the wiki page

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.

The gain of whitening filters on AS55 was decreased from 21 dB to 0 dB for the Y arm locking.

- - (Background)- -

Since the modulation depths became bigger from the past (#5462), the PDH signal from Y arm was saturated in the path of AS55.

Due to the saturation the lock of the Y arm became quite difficult so I decreased the gain of of the whitening filter from 21 dB to 0 dB.

In this condition, a required gain in C1:LSC-YARM_GAIN is about -0.3, which is 10 times bigger from the default number.

For the MICH locking tonight, it may need to be back to a big gain.

Since the MC wasn't able to capture the 00 mode in this morning I aligned the incident beam going to MC.

As a result C1:IOO-RFPD_DCMON went down to 0.6. However the beam on IPPOS is almost falling off from the QPD.

[Suresh / Kiwamu]

 The MC REFL camera is now available. The camera name is "MCR" and you can call it from the videoswitch script.

(what we did)

 + repositioned and aligned the MCR camera.

 + checked the MCR camera.

  => found the camera view shows a negative image (i.e. the beam spot is dark and the background is bright !!)

 + replaced the camera by a spare one.

 + modified the videoswitch script because the input channel 3 was wrongly assigned to MCR.

  MCR was correctly assigned to the input channel 18.

[Jenne / Kiwamu]

 Fb was sick. Dataviewer and Fourier Tools didn't work for a while.

After 10 minutes later they became healthy again. No idea what exactly was going on.

One thing we found was that : during the sickness of fb, it looks like daqd was restarting by hisself. Is this normal ??

Here is the bottom sentences of restart.log. Apparently daqd was rebooting although we didn't command to do so.

  daqd_start Tue Sep 20 02:41:17 PDT 2011
  daqd_start Tue Sep 20 13:18:12 PDT 2011
  daqd_start Tue Sep 20 17:33:00 PDT 2011

Did you take the 180 deg shift into your account ?

Since your measurement was done when the loop was closed, there must be an additional 180 deg phase shift (in other words, minus sign).

Found some LSC scripts didn't run on pianosa. Particularly all the scripts on the C1:IFO_CONFIGURE screen don't run.

They need to be fixed.

The output matrix in the C1ASS servo were coarsely readjusted and the servos seemed working.

However it is difficult to say the servo is very good or so-so,

because the ETMY suspension moves a lot and hence the cavity eigen axis moves a lot too.

(to do)

(Background)

It turned out the oplev controls on ETMY were just bad.

It looks like the whitening filters have been OFF and because of that the resultant open-loop was not crossing the unity gain.

I will check the whitening filters.

(open-loop transfer function)

The blue dots are the measured data points and the green curve is the fit.

Apparently the open-loop doesn't go above the unity gain, so the oplev had been doing nothing.

If we try to increase the overall gain it will oscillate because of the phase delay of more than 180 deg around 3 Hz.

The red curve is the expected one with the whitening filters (WFs) properly engaged.

Note that WF are supposed to have two zeros at 1 Hz and two poles at 10 Hz.

The whitening filters for the ETMY oplevs are back.

The whitening board had been in the rack but the ADC was connected directly to the oplev interface board without going through the whitening board.

In fact the interface board and the whitening board had been already connected. So the ADC was making a shortcut.

I disconnected the ADC from the interface board and plugged it to the output of the whitening board.

Here is an example of the new open-loop transfer function with the whitening filters.

 Note :

before the measurement I increased the control gain by an arbitrary number to obtain gain of more than 1 around 1 Hz.

As a suspension test I am leaving all of the suspensions restored and damped with OSEMS but without oplevs

[Koji / Kiwamu]

 The c1scx and c1x01 realtime processes became frozen. We restarted them around 1:30 by sshing and running the kill/start scripts.

Good work for the oplev noise simulations. Here are some comments/questions:

 (A) The noise looks suppressed but the open-loop transfer function doesn't look so good, because it doesn't have sufficient phase margins at the UGFs (0.01 and 10 Hz).

      I guess it is better to have a phase margin detector in your code so that the code automatically rejects a bad phase margin case.

      Actually since the number of data points are finite, the rms detector in the simulation can not always find a sharp loop oscillation.

 (B) The resultant poles and zeros seem canceling each other but the filter still has a structure. Is something wrong ?

The servo for aligning the Y arm is working fine with the coarse gain coefficients.

However then I found the ASS_Xarm servo was not healthy.

So the next step is to refine the X arm servo in C1ASS.

(some notes)

  + With the ETMY oplev the Y arm became quieter after we recovered the oplev whitening filter (#5523)

  + The Y arm alignment scripts can be run from the usual C1IFO_CONFIGURE screen.

   It will servo the spot positions on ITMY and ETMY, and align the input beam pointing. It brings the Y arm power to about 1.

 + The X arm servo is doing something funny. It doesn't bring the arm power up to 1.

   I thought the X arm didn't need any modifications because the X arm servo doesn't include PZT1 and PZT2.

   So it maybe a simple bug (for example, some switches are disable and so on)

According to the spectra, all of the suspensions had been damped with the OSEMs. The peaks around 1Hz are reasonably suppressed.

However the spectra from ITMX showed a noise floor at very high level. This is because of strange jumps in the signal of the UL shadow sensor.

I will check some analog circuits for the UL sensor.

(ITMX shadow sensors)

Here is the spectra of the ITMX shadow sensors taken during the damping test (#5534)- -

The UL sensor shows a unacceptable amount of noise.

Additionally I checked the time series of the ITMX shadow sensors and found ONLY the UL sensor frequently showed strange jumps in data.

Here is an example of the time series showing a jump ONLY in the UL sensor.

It is possible that the jumps are coming from some circuits, since the rest of the sensors (including the oplevs) don't detect the same jump.

Currently the damping of the ITMX suspension is intentionally disabled for the noise investigation.

The issue on the ITMX UL sensor has been fixed. It was because of a loose connection in the sensor signal path.

After the fix, the sensor responses completely changed and the suspension became unable to be damped with the new matrix.

At the moment the ITMX suspension is damped by the default input matrix.

we should do the free swinging test once again.

(details)

 The loose connection was found on the rear side of the 1X5 rack.

There is an adapter card on the rear side, where the driver and sensor signals are combined into a single cable.

I pushed the sensor cable (bottom right in the picture) and the noise disappeared.

Note that I changed the labels on the adapter cards from the old X/Y convention to the new one.

After fixing the loose cable the ITMX suspension became unable to be damped.

So I put the input matrix back to the default and it immediately started damping happily. It means our new matrix is not valid any more.

 Here is the latest noise spectra of the ITMX sensors damped with the default input matrix.

As usual all of them are limited by the ADC noise above 20 Hz. (ADC noise is plotted in purple curve)

During the work I also pushed not only ITMX ones but also the cable for the rest of the optics in the adapter cards.

Then PRM became unable to be damped, so it implies the PRM suspension also used to be the same situation.

The input matrix of PRM has been also back to the default.

The lock of PRMI wasn't so robust although it could stay locked for more than 10 minutes.

There have been 2-3Hz spikes in everywhere. It needs to be investigated.

(to do)

 + Diagnosis on the suspensions.

 + Check the beam centering on the RFPDs.

 + Check the f2a filters on PRM and BS.

 + Health check of the suspensions by locking some cavities and measuring the noise spectra for comparison.

 + Trying to use another signal port other than AS55.

(Spikes)

 The attached picture below is an example of the REFLDC and POXDC signals in time series.

This was when PRCL and MICH were locked by REFL33_I and AS55_Q respectively.

Note that when PRMI is unlocked, REFLDC goes to ~ 5000 counts and POXDC goes within ADC noise of ~ 1 counts.

According to the POP camera it looked like something was oscillating in the YAW direction which coincided with the spikes.

I tried finding any suspicious angular motions in the ITMs, BS and PRM olevs, but none of them showed the 2-3 Hz feature.

Somehow some DAQ channels for C1SUS have disappeared from the DAQ channel list.

Indeed there are only a few DAQ channels listed in the C1SUS.ini file.

I ran the activateDQ.py and restarted daqd.

Everything looks okay.  C1SUS and C1PEM were restarted because they became frozen.

The channels for IPPOS had been assigned in a wrong way.

Because of this, C1:ASC-IP_POS_X_Calc corresponds to the actual vertical motion and C1:ASC-IP_POS_Y_Calc is for the horizontal motion.

We should fix the database file to get the correct vertical/horizontal corrdinate.

Now the C1ASS servos are working fine.

However at the end of the scripts sometimes it changes the DC force (e.g. C1:SUS-ITMX_PIT_COMM and so on) by a wrong amount.

So for this bug, it misaligns the suspensions a lot. I will take a look at the script tomorrow.

[Suresh/Kiwamu]

We found that the C1LSC.ini and C1IOO.ini file had been refreshed and there were a few recorded channels in the files.

So we manually recovered C1LSC.ini file using the daqconfig GUI screen.

For the C1IOO.ini file we simply replaced it by the archived one which had been saved in 22nd of September.

Then we restarted daqd.

[Suresh / Kiwamu]

The c1lsc and c1sus machine were rebooted.

- - (CDS troubles)

 After we restarted daqd and pressed some DAQ RELOAD buttons the c1lsc machine crashed.

The machine didn't respond to ssh, so the machine was physically rebooted by pressing the reset button.

Then we found all the realtime processes on the c1sus machine became frozen, so we restarted them by sshing and typing the start scripts.

However after that, the vertex suspensions became undamped, even though we did the burt restore correctly.

This symptom was exactly the same as Jenne reported (#5571).

We tried the same technique as Jenne did ; hardware reboot of the c1sus machine. Then everything became okay.

The burt restore was done for c1lsc, c1asc, c1sus and c1mcs.

- - (ITMX trouble)

During the trial of damping recovery, the ITMX mirror seemed stacked to an OSEM. The UL readout became zero and the rest of them became full range.

Eventually introducing a small offset in C1:SUS-ITMX_YAW_COMM released the mirror. The amount of the offset we introduced was about +1.

The MICH and PRCL motions have been measured in some different configurations.

According to the measurements :

      + PRCL is always noisier than MICH.

      + MICH motion becomes noisier when the configuration is Power-Recycled Michelson (PRMI).

The next actions are :

      + check the ASPD

      + check the demodulation phases

      + try different RFPDs to lock MICH

Thank you for the summary.

I think now you are getting into a phase where you should start doing some quantitative and careful checks.

    1. Calculate how much light will be reflected from the cavity if the alignment is perfect.

    2. Investigate where those kHz oscillations are coming from.

    3. Estimate how much the 1.1 kHz corner frequency in LPF will reduce the phase margin around 10 kHz.

    4. Calculate the estimated amplitude of the PDH signal.

    5. Compute how big the gain of the PDH box should be.

[Mirko / Kiwamu]

 We have reviewed the AM issue and confirmed the ratio of AM vs. PM had been about 6 x10³.

The ratio sounds reasonably big, but in reality we still have some amount of offsets in the LSC demod signals.

Next week, Mirko will estimate the effect from a mismatch in the MC absolute length and the modulation frequency.

(Details)

 Please correct us if something is wrong in the calculations.

 According to the measurement done by Keiko (#5502):

        DC = 5.2 V

        AM @ 11 and 55 MHz = - 56 dBm = 0.35 mV (in 50 Ohm system)

Therefore the intensity modulation is 0.35 mV / 5.2 V = 6.7 x 10^-5

Since the AM index is half of the intensity modulation index, our AM index is now about 3.4 x 10^-5

According to Mirko's OSA measurement, the PM index have been about 0.2.

As a result,  PM/AM = 6 x 10³

Found the Marconi for the 11 MHz source had been reset to its default.

 => reset the parameters. f = 11.065910 MHz (see #5530) amp = 13 dBm.

Interferometer became lockable. I checked the X/Y arm lock, and MICH lock, they all are fine.

The following optics were kicked:
MC1 MC2 MC3 ETMX ETMY ITMX ITMY PRM SRM BS
Sun Oct  2 02:13:40 PDT 2011
1001582036

They will automatically get back after 5 hours.

Just a quick report.

The AS55 signal contains more noise than the REFL signals.

Why ? Is this the reason of the instability in PRMI ?

 I locked the Power-Precycled ITMY with REFL33.

As shown in the plot above, I compared the in-loop signal (REFL33) and out-of-loop signals (REFL11 and AS55).

All the signals are calibrated into the displacements of the PR-ITMY cavity by injecting a calibration peak at 283 Hz through the actuator of PRM.

AS55 (blue curve) showed a structure around 3 Hz and higher flat noise below 1 Hz.

The input matrices of ETMX, ITMX and PRM have been newly inverted.

Those were the ones having some troubles (see #5444, #5547).

After a coarse adjustment of the damping Q factors, they look damping happily.

optic	spectra	inverted matrix	BADNESS
ETMX		pit     yaw     pos     side    butt UL    0.848   0.108   1.578   0.431   1.025  UR    0.182  -1.892   1.841  -0.128  -1.172  LR   -1.818  -1.948   0.422  -0.122   0.939  LL   -1.152   0.052   0.159   0.438  -0.864  SD    1.756  -3.794  -0.787   1.000  -0.132	5.37028
ITMX		pit     yaw     pos     side    butt UL    0.510   0.584   1.228   0.458   0.203  UR    0.783  -1.350   0.348  -0.050   0.555  LR   -1.217   0.065   0.772   0.264   0.312  LL   -1.490   2.000   1.652   0.772  -2.930  SD   -0.635   0.853  -1.799   1.000  -1.597	7.5125
PRM		pit     yaw     pos     side    butt UL    0.695   1.422   1.774  -0.333   0.954  UR    1.291  -0.578   0.674  -0.068  -0.939  LR   -0.709  -1.022   0.226   0.014   0.867  LL   -1.305   0.978   1.326  -0.251  -1.240  SD    0.392  -0.437  -0.500   1.000   0.420	5.09674

(some notes)

 Before running the peakFit scripts, I woke up the nds2 sever process on Mafalda because it hasn't been recovered from the power outage.

To start the nds2 process I followed the instruction by Jamie (#5094).

Then I started requesting the data of the last night's free swinging test (#5594)

However the NDS2_GetData command failed everytime when data with long duration were requested.

It maybe because some of the data are missing in sometimes, but I haven't seriously checked the data stored in fb.

So for the reason, I had to use a short duration of 1200 sec (default is 3600 sec). That's why spectra look noisier than usual.

My goal of today was to lock PRMI without using AS55 and it is 50% successful.

The sideband-resonance PRMI (SB-PRMI) was locked with REFL33_I and REFL55_Q for the PRCL and MICH control respectively.

The carrier-resonance PRMI wasn't able to be locked without AS55.

     (it looked no clean MICH signals at the REFL ports.)

(Motivation)

 The motivation of not to use AS55 came from the suspicion that AS55 was injecting some noise into MICH (#5595).

So I wanted to try another RFPD to see if it helps the stability or not. 

(locking activity)

  The lock of SB-PRMI was quite stable so that it stayed locked more than 30 minutes (it ended because I turned off the servos.)

Then I briefly tried DRMI while PRCL and MICH kept locked by the same control loops, namely REFL33_I and REFL55_Q.

The lock of MICH and PRCL looked reasonably robust against the SRCL fringes, but wasn't able to find a good signal for SRCL.

I think I am going to try locking DRMI tomorrow.

 - - settings

    Demod phase for REFL55 = -45.3 deg

    Demod phase for REFL33 = -14.5 deg

    Whitening gain for REFL55 = 4 (12 dB)

    Whitening gain for REFL33 = 10 (30 dB)

    MICH gain = 100

    PRCL gain = 8

(misc.)

 + I removed an iris on the ITMY table because it was in the way of POY. See the picture below.

  + I found that burtrestore for the ETMX DC coil forces were not functional.

  => currently ETMX's "restore" and "mislalign" buttons on the C1IFO_ALIGN screen are not working.

  => According to the error messages, something seemed wrong on c1auxex, which is a slow machine controlling the DC force.

The input matrix of IPPOS were fixed so that the horizaontal motion correctly shows up in X and the vertial is Y.

(what I did)

 + The data base file, QPD.db, were edited.

  QPD.db is a part of the c1isxaux slow machine and it determines the input matrix for deriving the X/Y signals from each quadrant element.

 + The previous input matrix was :

      X = (SEG1 + SEG4) - (SEG2 + SEG3)

      Y = (SEG1 + SEG2) - (SEG3 + SEG4)

 + The new matrix which I set is :

     X = (SEG1 + SEG2) - (SEG3 + SEG4)

     Y = (SEG1 + SEG4) - (SEG2 + SEG3)

    The new matrix is a just swap of the previous X and Y.

 + Then c1isxaux was rebooted by :

     telnet  c1iscaux

     reboot          

 + The I did the burt restore it to this morning.

[Mirko / Jenne / Kiwamu]

Just a quick update. All the realtime processes on the c1lsc and c1sus machine didn't run at all.

Somehow the c1xxxfe.ko kernel module, where xxx is x04, x02, lsc, ass, sus, mcs, pem and rfm failed to be insmod.

The timing indicators on the c1lsc and c1sus machine are saying NO SYNC.

- According to log files (target/c1lsc/logs/log.txt)

insmod: error inserting '/opt/rtcds/caltech/c1/target/c1lsc/bin/c1lscfe.ko': -1 Unknown symbol in module

- dmesg on c1lsc (c1sus also dumps the same error message):

[   45.831507] DXH Adapter 0 : sci_map_segment - Failed to map segment - error=0x40000d01
[   45.833006] c1x04: DIS segment mapping status 1073745153

DXH dapter is a part of the Dolphine connections.

When a realtime codes is waking up, the code checks the Dolphin connections.

The checking procedure is defined by dolphin.c (/src/fe/doplhin.c).

According to a printk sentence in dolphin.c the second error message listed above will return status "0" if everything is fine.

The first error above is an error vector from a special dolphin's function called sci_map_segment, which is called in dolphin.c.

So something failed in this sci_map_segment function and is preventing the realtime code from waking up.

Note that sci_map_segment is defined in genif.h and genif.c which reside in /opt/srcdis/src/IRM_DSX/drv/src.

[Koji / Kiwamu]

 We did several tests to figure out what could be a source of the computer issue.

The Dolphin switch box looks suspicious, but not 100% sure.

(what we did)

 + Removed the pciRfm sentence from the c1x04 model to disable the Dolphin connection in the software.

 + Found no difference in the Makefile, which is supposed to comment out the Dolphin connection sentences.

   ==> So we had to edit the Makefile by ourselves

 + Did a hand-comilpe by editing the Makefile and running a make command.

 + Restarted the c1x04 process and it ran wihtout problems.

   ==> the Dolphin connection was somehow preventing the c1x04 process from runnning.

 +  Unplugged the Dolphin cables on the back side of the Dolphin box and re-plug them to other ports.

   ==> didn't improve the issue.

 + During those tests, c1lsc frequently became frozen. We disabled the automatic-start of c1lsc, c1ass, c1oaf by editting rtsystab.

  ==> after the test we reverted it.

 + We reverted all the things to the previous configuration.