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ID Date Author Type Category Subject
  8638   Fri May 24 11:38:00 2013 KojiUpdate40m upgradingETMY - Mode Matching for green

I got confused. Is the mode calculation in the cavity correct?
Are you sure the wavelength in the code is 532nm?

The first plot says "the waist radius at ITMY is 2.15mm". This number is already very close to
the waist size of the cavity mode (2.1mm@ITM, 3.7mm@ETM), but the spot radius at ETMY is 6mm.
They are inconsistent.

 

  8637   Fri May 24 02:12:50 2013 AnnalisaUpdate40m upgradingETMY - Mode Matching for green

 

 Mode Matching calculation for green beam - Yarm

After measuring the beam radius out from the Faraday for the green, I made the calculation to match the green beam mode with the IR mode inside the arm.

The beam waist after the Faraday is elliptical, and I found the following value for the waist:

w0x = 3.55e-5 m @ z0x = -0.042 m

w0y = 2.44e-5 m @ z0y = -0.036 m

(the origin of the z axis is the output of the Faraday, so the waist is inside the Faraday itself)

I did the calculation using a la mode, using as beam waist and its position the following values:

w0 = sqrt(w0x*w0y) = 2.943e-5 m @ z0 = (z0x+z0y)/2 = -0.039 m

The results are shown in the attached plots.

                      Focal length (m)             position (m)

lens1            0.125                                0.1416

lens2            0.100                                0.5225

L                    1.000                                1.5748 (fixed lens used to focus transmitted beam)

 

As the first plot shows, the green beam size on the ETMY is about 6mm. My concern is that it could be too big.

The third plot shows the X and Y section of the beam. It is strongly elliptical, but nevertheless the coupling factor calculated with Koji's formula  gives C=0.936 for the astigmatic beam, and C=0.985 for the non astigmatic beam, so it seems to be still ok.

 

 

Attachment 1: ModeMatchingGreen.jpg
ModeMatchingGreen.jpg
Attachment 2: ModeMatchingGreenZoom.jpg
ModeMatchingGreenZoom.jpg
Attachment 3: XYpath.jpg
XYpath.jpg
  8636   Thu May 23 22:13:12 2013 KojiUpdateLSCPRMI sensing matrix measured at 580.1Hz

Can you clarify the definition of the phase "0deg" of your plot?

Is "I" the definition of "0deg"? Or does the demod phase of "0deg" define "0deg"?

I want to know if the demod phase of REFL55 is correctly adjusted or not.

With the decent level of the separation, we should be able to keep the decent lock of PRMI with REFL55.

  8635   Thu May 23 21:45:51 2013 JenneUpdateLSCSensing matrix scripts now check for lockloss

A few more small mods to the sensing matrix script.  Now the script saves the data after each measurement, so that in case you lose lock and can't measure any more, you still have the data you already measured.  Also, the error bar measurements are last, so that the consequence of losing lock partway through the measurement is just that you get fewer error bar numbers.  Not a big deal, since the actual sensing matrix data is already saved.

Also, the old script had a lockloss checker that I had overridden since it wasn't where I wanted it.  I have now re-implemented it, so that the script will stop the oscillation and quit measuring if either the LSC enable switch is off, or the degrees of freedom you're trying to measure are not triggered.  All data saved before the lockloss is saved though (as mentioned above).

  8634   Thu May 23 20:58:49 2013 JenneUpdatePEMPRM, ITMX optics tripped, restored

M5.7 - 11km WNW of Greenville, California

Time
Location
40.190°N 121.064°W
Depth
0.0km
  8633   Thu May 23 20:39:50 2013 JenneUpdateLSCPRMI sensing matrix measured at 580.1Hz

I locked the PRMI and remeasured the sensing matrix, this time at 580Hz.  The excellent news here is that the matrix looks quite similar to the one measured the other day, recorded in elog 8632.  Yay!  I'm not sure why the REFL11 MICH error is so much larger this time around.

Raw data:  .../scripts/LSC/SensMatData/sensematPRM_2013-05-23.202312.dat

Sensing Matrix, units = cts/meter, phase in degrees
 
            PRCL Mag   PRCL Phase    MICH Mag   MICH Phase  
AS55        5.485E+08   162.424      2.679E+09    25.608     
REFL11      1.126E+13  -122.832      1.618E+11    85.296     
REFL33      2.658E+11   -87.973      8.910E+09    79.226     
REFL55      3.012E+11   -99.534      1.210E+10    12.486 

     SensMat_23May2013.png

  8632   Thu May 23 19:09:15 2013 JenneUpdateLSCSensing matrix scripts modified to include actuator calibration

After fixing up my calculations in my scripts, I have calculated the final PRMI sensing matrix (as measured very close to the violin frequency, so things may not be perfect). The data is from the file that Koji mentioned in his elog when he did the measurement:  elog 8611, sensematPRM_2013-05-22.12615.dat

Sensing Matrix, units = cts/meter, phase in degrees
 
            PRCL Mag   PRCL Phase    MICH Mag   MICH Phase  
AS55        1.064E+09   141.880      3.442E+09    11.929     
REFL11      3.474E+13  -108.372      4.316E+11   106.143     
REFL33      3.242E+11   -90.392      1.080E+10    81.037     
REFL55      3.373E+11   -92.060      1.394E+10    15.153 

SensMat_21May2013.png

In the plot, the little blobs on the ends of the 'sticks' are the error blobs.  Many of them are smaller than is really visible - this is good.  These errors come from measuring the lockin outputs several times while there is no drive to any optics, then the errors are propagated to each degree of freedom.  These errors do not incorporate any information about the precision of the actuator calibration, and they assume that the shape of all the sensor transfer functions are the same. 

If you look at the REFL11 and REFL33, it kind of seems like a miracle that we've ever been able to lock the full PRMI with the I&Q signals from either PD!

  8631   Thu May 23 17:51:39 2013 KojiSummaryLSCMy usual locking procedure

For purpose of the automation and my record, I summarized my locking procedure as a chart.

Attachment 1: PRMI_locking_procedure.pdf
PRMI_locking_procedure.pdf PRMI_locking_procedure.pdf
  8630   Thu May 23 14:45:08 2013 JenneUpdateLSCSensing matrix scripts calculations make more sense now

I think I have most of the magnitude issues figured out now. 

First of all, the lockin outputs are different from the actual responses in the PDs by a factor of 2. 

If the optic is driven with amplitude D, it will have a response of Asin(wt) + Bcos(wt) + other frequency junk.  The lockin bandpasses the response to get rid of the 'other frequency junk'.  Then creates 2 new signals, one multiplied by cos(wt), the other multiplied by sin(wt).  So, now we have Asin^2(wt) + Bcos(wt)sin(wt) and Asin(wt)cos(wt) + Bcos^2(wt).   If I rewrite these, I have A/2*(1-cos(2wt))+B/2*(sin(2wt) and A/2*sin(2wt)+B/2*(1+cos(2wt)).  We lowpass to get rid of the 2w components, and are left with A/2 for the Q-phase, and B/2 for the I-phase of the lockin outputs.  Since the real amplitudes of the response were A for the Q-phase and B for the I-phase, we need to multiply the lockin outputs by 2.

The other problem was that in the 'uncalibrated' version of numbers that I was printing to compare with Koji's, I had not normalized by the drive amplitude yet.  That happens in the "calibration" part of my script.  So, if I go back to comparing the calibrated versions of our numbers, I get quite close to Koji's answers.

For the PRCL magnitudes, 3 of the 4 numbers match to ~5%.  However, the MICH magnitudes all seem to be off by a factor of 2.  I'm still stuck on this factor of 2, but I'm thinking about it. Also, the phases that Koji and I get are pretty different.

Koji's sensing matrix:

Sensing Matrix, units = cts/meter, phase in degrees
            PRCL Mag   PRCL Phase    MICH Mag   MICH Phase  
REFL33_I    3.100E+11  -109.727      4.900E+09    74.434     
REFL33_Q    3.300E+09  -141.730      7.900E+08    71.120     
REFL55_I    3.200E+11  -109.672      5.900E+08    77.313     
REFL55_Q    1.200E+10  -143.169      6.500E+09    91.559  

My sensing matrix:

Sensing Matrix, units = cts/meter, phase in degrees
            PRCL Mag   PRCL Phase    MICH Mag   MICH Phase  
REFL33_I    3.242E+11  -157.846      1.067E+10    19.010     
REFL33_Q    2.217E+09  -104.088      1.683E+09    28.731     
REFL55_I    3.371E+11  -157.915      3.645E+09    11.072     
REFL55_Q    1.213E+10  -118.348      1.346E+10     2.847

Here are the plotted versions of these matricies:

SensMat_KojiMeas_23May2013.png

SensMat_JenneMeas_23May2013.png

SOME EDITS:  Koji's measurement was 1Hz away from the violin mode, while mine (him running my script) was at the violin mode, so the sensor TFs were actually taken at slightly different frequencies. This helps explain the discrepancies.

Also, the phase in these plots isn't correct, so I need to figure that out. Corrected version of the 'koji' measurement put in place of the incorrect one.  I convert from radians to degrees for my script, but Koji had already reported his phases in degrees, so when I multiplied by 180/pi, it didn't make any sense. I now convert his numbers to radians before running them through my analysis script.

 

  8629   Thu May 23 13:14:34 2013 KojiSummaryLSCXarm beat note search continues

We should consider to hook up the temperature monitors of the NPROs to the ADCs.

  8628   Thu May 23 12:02:48 2013 SteveUpdateendtable upgradeETMY - oplev

 Temporary oplev in place. The spot on the qpd is still big. My two lens solution did not work.

I will finalize optical component position of the oplev after the the arm transmitted and green beam optics in place. They have priority.

 

Attachment 1: ETMYopl.jpg
ETMYopl.jpg
  8627   Thu May 23 10:48:42 2013 ManasaUpdateIOOMC autolocker and MCWFS enabled

Some strong seismic noise (not related to any earthquakes - watchdogs are all green) had got the MC unlocked this morning.

I found the MC autolocker and MCWFS disabled. Enabling them locked the MC right away. I don't see any updates in the elog  as to why these were left disabled and hence have left them ON now.

  8626   Thu May 23 10:24:23 2013 JamieSummaryCDSc1scy model continues to run at the hairy edge

c1scy, the controller model at the Y END, is still running very long, typically at 55/60 microseconds, or ~92% of it's cycle.  It's currently showing a recorded max cycle time (since last restart or reset) of 60, which means that it has actually hit it's limit sometime in the very recent past.  This is obviously not good, since it's going to inject big glitches into ETMY.

c1scy is actually running a lot less code than c1scx, but c1scx caps out it's load at about 46 us.  This indicates to me that it must be some hardware configuration setting in the c1iscey computer.

I'll try to look into this more as soon as I can.

  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).

  8624   Thu May 23 01:27:11 2013 ManasaSummaryLSCXarm beat note search continues

Towards finding the x-arm beat note:

The green would not lock to a maximum GTRX this morning. In the course of aligning the green stably to the X arm, somewhere down the line, the input pointing got messed up (reasons unknown). To set this right, Koji tried to lock the Yarm with POY DC but it wouldn't work. The transmon for Y had to be set up temporarily and the Y arm was locked with TRY. This restored the input pointing and the arms locked with transmission TRX/TRY > 0.9 counts. The transmon path along the Y arm was then re-configured as mentioned in Annalisa's elog.

I still had trouble getting the X-green locked in TEM00 (similar situation mentioned by Jenne in elog). The arm cavity mirrors were tweaked to get the green to resonate in TEM00 but it wouldn't stay locked when the temperature of the x-end NPRO was changed. Koji helped recover missing links to filters for the ALS_X_SLOW servo from the archives. Enabling the filters helped keep the green locking stable for laser temperature changes (which corresponds to 'offset' change in ALS_X_SLOW servo screen).

PSL green alignment was checked once again and the X-end laser temperature was scanned trying to find the beatnote. RFMON from the beatbox was connected to the spectrum analyzer. I have scanned through the whole range of offset but have not been able to find the beat note yet.


The search will continue tomorrow

  8623   Thu May 23 00:49:13 2013 JenneUpdateLSCLSC filters loaded

Quote:

 To avoid exciting at the PRM violin mode frequency, I have changed all of the filters relevant to the sensing matrix measurement from 628Hz to 580.1Hz.  This includes notches in the LSC control loops, as well as the band pass filters in the lockins.  I have not yet loaded the new filters, since arm locking is in progress.

 I have loaded these new filters in.  Manasa is still using the IFO for green stuff, so I can try out the PRMI measurement in a day or so.  (Right now I have to make sure I understand my data, anyway.)

  8622   Thu May 23 00:16:32 2013 AnnalisaUpdate40m upgradingETMY - progress

 [Annalisa, Koji] 

 GREEN

I aligned back the beam (we lost part of the alignment after we put back the box and after the posts were installed). The green beam out from the crystal is still low, but anyway I get about 1.2 mW of green out from the Faraday. 

TO DO 

Mode Matching calculation (tomorrow)

Fix the dumping situation

Replace some of the mounts with more solid ones (in the future)

TRANSMON PATH

 QPD, PD and Camera have been rotated as Rana suggested last Wednesday. A 1m focal length lens is on the main beam transmitted path (before the harmonic separator), and the beam diameter on the QPD is about 5mm. We put another lens with a shorter focal length to put the PD very close to the beam waist and in way to have a reasonable beam size on the camera. Tomorrow I will write down all the correct sizes of the beams.

OPLEV 

(for Steve) I marked a possible beam path for the Oplev (the laser is not in the right place in the picture, but I left it in the correct place on the table). I also put the QPD for the IP-ANG, so we know in which part of the table the beam can be steered.

The space in the red rectangle (right corner) has to be left empty to put a PD for the rejected beam from the green Faraday.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Attachment 1: TransMonAndOplev.jpg
TransMonAndOplev.jpg
  8621   Wed May 22 20:50:26 2013 JenneUpdateLSCSensing matrix scripts don't calculate correctly

I am trying to re-analyze the data that Koji took last night.  

I think that my script is just pulling out the I and Q data for each port, and each degree of freedom, calculating the magnitude from sqrt( I**2 + Q**2 ) and the phase from atan2( I / Q ).  No calibration.

If I print out the results, I get:

Sensing Matrix, units = cts/ct, phase in degrees
 
            MICH Mag   MICH Phase    PRCL Mag   PRCL Phase  
AS55_I      1.627E-02   62.063        4.189E-03   68.344       
AS55_Q      2.073E-02  -105.353        1.983E-02   66.361       
REFL11_I    8.165E+02  -112.624        2.441E+00   77.911       
REFL11_Q    2.712E+02  -112.650        7.065E-01  -127.093       
REFL33_I    8.028E+00  -112.154        6.282E-02   70.990
       

REFL33_Q    5.490E-02  -165.912        9.908E-03   61.269       

REFL55_I    8.347E+00  -112.085        2.146E-02   78.928       
REFL55_Q    3.003E-01  -151.652        7.924E-02   87.153
 

If, however, I take the raw values that are stored in the data file, for one row (say, REFL33_Q) and calculate by hand (same formulas), I get different results:

            MICH Mag   MICH Phase    PRCL Mag   PRCL Phase  
REFL33_Q    9.9E-03    28.89         5.46E-02   -103.8

Contrast that with Koji's uncalibrated transfer function result from elog 8611:

            MICH Mag    MICH Phase    PRCL Mag     PRCL Phase  
REFL33Q     1.8665e-5   71.1204      
1.6310e-4    -141.73

 

I am currently confused, and need to re-look at my script, as well as make sure I am actually measuring the things I think I am.

EDIT:  This has been fixed, in that my 2 calculations agree with one another.  I have crossed out the incorrect numbers, and put correct numbers below.  I still don't agree with Koji, but at least I agree with myself. 

The phase issue:  I needed to calculate the phase with "ATAN2(I,Q)", which I did when I calculated by hand, but the script had "atan2(Q,I)".  This has been fixed. 

The magnitude issue:  They match, but my "pretty print" script labels MICH as PRCL, and vice versa.  Doh.

Corrected values:

Sensing Matrix, units = cts/ct, phase in degrees
 
            PRCL Mag   PRCL Phase    MICH Mag   MICH Phase  
AS55_I      1.627E-02    27.937      4.189E-03    21.656     
AS55_Q      2.073E-02  -164.647      1.983E-02    23.639     
REFL11_I    8.165E+02  -157.376      2.441E+00    12.089     
REFL11_Q    2.712E+02  -157.350      7.065E-01  -142.907     
REFL33_I    8.028E+00  -157.846      6.282E-02    19.010     
REFL33_Q    5.490E-02  -104.088      9.908E-03    28.731     
REFL55_I    8.347E+00  -157.915      2.146E-02    11.072     
REFL55_Q    3.003E-01  -118.348      7.924E-02     2.847 

  8620   Wed May 22 18:24:19 2013 JenneUpdateSUSViolin mode survey

Quote:

It was too embarassing to see that the actuation frequency was set at the violin mode frequency in order to avoid designing a new filter!?

 Ooops, definitely my bad.  I think I was the one who put in the PRM violin filter, so I should have recognized that frequency.  However, I couldn't think of a reason why violin mode filters should be in the LSC filter banks, since we usually put them in C1:SUS-optic_LSC filter banks. 

Anyhow, so that I don't make a mistake like that again, I was looking through all of the violin mode filters for all the optics, so I could write down the frequencies.  The result: confusion.

Violin filters in C1:SUS-optic_LSC filter banks:

The PRM's violin mode filter is set correctly to 627.75Hz:  elog 8533.

One of BS or SRM has probably been measured (presumably BS), since they have the same filters centered around 645Hz. 

Neither ITM has a violin filter.

The ETMs have violin filters in the 440's, which I assume was correct back in the MOS days, before 2010.

Vio2 filters in C1:SUS-optic_LSC filter banks:

PRM, SRM, BS, ITMX, ITMY:  Centered around 1285 Hz, which matches the violin notch frequencies in the BS and SRM.

ETMY:  Centered around 883.5Hz, which matches the old 440Hz frequency

ETMX:  Centered around 631Hz .  So, this could have been measured, but it was put into the wrong filter module.

 

Koji tells me that we don't really need to worry about all these violin filters unless they are required (as with the PRM and the obnoxious hum a few weeks ago), so I 'm not going to do any measuring / adjusting of these filters for now.

  8619   Wed May 22 18:07:36 2013 JenneUpdateLSCKiwamu's sensing matrix measurement script revived

 

 To avoid exciting at the PRM violin mode frequency, I have changed all of the filters relevant to the sensing matrix measurement from 628Hz to 580.1Hz.  This includes notches in the LSC control loops, as well as the band pass filters in the lockins.  I have not yet loaded the new filters, since arm locking is in progress.

 

  8618   Wed May 22 17:29:34 2013 JenneUpdateASCQPD for POP ASC tested

I fiddled around with the QPD that I'll use to replace Koji's temporary razor blade yaw sensor for detecting POP beam angular motion, and checked that it is working. 

Using the Jenne Laser, I put beam onto the 4 different quadrants of the QPD, and saw that the Sum channel remained constant. 

   * I had the room lights off, since the PD elements are silicon. 

   * Beam size on the QPD as seen on an IR card was ~1mm diameter.

   * With the beam on the QPD, I chose gain setting "G2" on the amplifier, since that was the only setting where neither the "current too high" nor the "current too low" LEDs were illuminated.  I didn't measure the power going to the PD, but the Jenne Laser puts out 1.2mW, and there's a 50/50 BS, so I was getting about 600uW. 

   * I turned off the "zero/cal" switch on the back of the box, since I don't know how to set the zero.  Since the X and Y channels are normalized by the Sum, you can't just block all light going to the PD and set the zero.  There isn't a big change in the output levels with the zero/cal switch off, so I think it should be fine.  (Previously, I set all 4 knobs - "zero" and "cal" for each X and Y - to approximately the center of their ranges.  Once you hit the end of the range, you can keep turning the knob, but something inside makes a clicking sound ~once per revolution, and the signal level stops changing (for the zero knobs). Much like centering a beam on a PD, I found each edge of the range for each knob, and set the knobs in the centers by counting the number of turns.  Anyhow, since I set the knobs to ~halfway, I think that explains why there isn't really a change whether the "zero/cal" switch is on or off.

   * Using the steering mirror sending the beam to the QPD, I moved the beam around, and watched where I was going with an IR viewer.  I see that as I move from quad-to-quad, the X and Y channels respond as I expect.  If I only move the beam in X, I only see X response on a 'scope, and vice versa.

I can't do a real calibration until I get the QPD installed in place, so I can use the actual beam, but for now it looks like the QPD is responding nicely.  Since Annalisa and Manasa are using the Arms for the evening, I'll work on putting the QPD on the POX table tomorrow.

  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.

  8616   Wed May 22 15:08:37 2013 KojiSummaryCDSWeird DAC bit flipping at half integer output values

It seems that the effect is from the (linear) residual fluctuation of the digital AI filter for the zero-padded signal.

Namely, if we give the larger constant number, we get more oscillation.

Attachment 1: Screenshot.png
Screenshot.png
  8615   Wed May 22 11:35:06 2013 JamieSummaryCDSWeird DAC bit flipping at half integer output values

Quote:

Is this limit cycle caused by the residual of the digital AI filtering at the half sampling freq and that his the threshold?
Or is this some nonlinear effect? If this is a linear effect associated with the zero-padding, the absolute
value of the DC may affect the amplitude of the oscillation. (Or equivalently the range of the DC where we get this oscillation.)

This is a good question.  We may be able to test if it's a linear effect if we have enough DAC range to get the oscillation to be more than a single sample.

Quote:

You pointed out the ringdown of the digital AI filter in the sample-hold case (i.e. no-zero-padding case).
How does it look like in the conventional zero-padding case?

 In the zero-pad case the oscillation just continues indefinitely at the half-count value, so it never dies out (at least as far as I can tell).

  8614   Wed May 22 11:21:28 2013 KojiSummaryCDSWeird DAC bit flipping at half integer output values

Is this limit cycle caused by the residual of the digital AI filtering at the half sampling freq and that his the threshold?
Or is this some nonlinear effect? If this is a linear effect associated with the zero-padding, the absolute
value of the DC may affect the amplitude of the oscillation. (Or equivalently the range of the DC where we get this oscillation.)

Anyway, it seems that we should use no-zero-padding.

You pointed out the ringdown of the digital AI filter in the sample-hold case (i.e. no-zero-padding case).
How does it look like in the conventional zero-padding case?

  8613   Wed May 22 11:09:33 2013 JamieSummaryCDSWeird DAC bit flipping at half integer output values

After querying CDS folks about this issue, I got some responses that indicated the problems was likely limit-cycle oscillations due to zero-padding of the data when upsampling.  Tobin ran some Matlab tests to confirm this issue.

Starting in RCG 2.5 there is a new "no_zero_pad=1" cdsParameters option turns zero padding OFF.  I tried enabling this option c1scy to see how the behavior changed.  Sure enough, the 32 kHz oscillations mostly went away.  There are no oscillations for outputs held at the half-count value, and the oscillations around the half-count transitions went away as well.

The only thing I could see is a bit of oscillation when converging on a constant half-count value that went away after a couple of milliseconds:

nopad.pdf

So we might consider adding the no_zero_pad=1 option to all of our coil driver outputs, which might eliminate the need to add notches at the Nyquist in the analog anti-image filters

  8612   Wed May 22 00:42:13 2013 KojiSummarySUSviolin Q

While looking at the decay of the violin mode of the PRM, I made a simple measurement of the decay rate.

Error signal: REFL33I

The peak @628Hz became 0.372 to 0.303 in 60 sec.

-> Half life of the amplitude T_{1/2} is 203sec.

Q = 4.53 f0 T_{1/2} = 5.8 x10^5

  8611   Wed May 22 00:08:19 2013 KojiUpdateLSCSensing matrix scripts modified to include actuator calibration

It was too embarassing to see that the actuation frequency was set at the violin mode frequency in order to avoid designing a new filter!?

I ran Jenne's sensing matrix code and the immitated the same result by manual measurement with DTT.
I noticed that the PRM excitation was not transmitted to the mirror. I tracked down the cause and found that
Jenne is using 628Hz which is the notch frequency of the viloing filter.

There is no way we can measure the precise calibration of the error signal exactly at the violin mode frequency.

Nevertheless I waited for the ringdown of the violin mode to the floor level and ran the code again WITH the violin mode filter OFF
at PRM SUS.

The result was stored in the data file

sensematPRM_2013-05-22.12615.dat

The code spit the message at the end

Sensing Matrix, magnitude only, units = cts/meter
 
            MICH          PRCL         
AS55        5.304E+08     1.716E+09     
REFL11      1.732E+13     2.151E+11     
REFL33      1.616E+11     5.384E+09     
REFL55      1.681E+11     6.950E+09

Now I replicated the same measurement with DTT.

MICH or PRCL were excited with the lockin. In order to aviod the violin mode, I shifted the excitation freq by 1Hz. (i.e. 629.125Hz)

The peaks in REFL33I/Q and RFL55I/Q were observed with PSD and TF. The spectrum was measured with the FLATTOP window with the line resolution of 0.1Hz
DTT suggested that this corresponds to the BW of 0.471271Hz if I correctly understood what DTT plot said. We need this information to convert cnt/rtHz to cnt_pk
if we need. For the TF measurements, I needed to find the excitatin monitor but I could not. Therefore, I set the offset of LSC-LOCKIN1_SIG to be 1000,
so that C1:LSC-LOCKIN1_I_IN1 produce the same signal as the excitation.

Note that during the measurement, 628Hz nothces in the LSC servos were on. I confirmed that this provides the reduction of the feedback by a factor of 76.
As the original openloop gain at 629Hz is lower than the unity more than a factor of 2, this was sufficient attenuation to measure the optical gain with the systematic error of less than a %.

MICH excitation (ITMX -1, ITMY +1)
        PSD (cnt/rtHz)   TF Mag    Phase

REFL33I 0.098590         9.5691e-5 74.4344
REFL33Q 0.019294         1.8665e-5 71.1204
REFL55I 0.016123         1.3890e-5 77.3132
REFL55Q 0.157522         1.5285e-4 91.5594

PRCL excitation (PRM +1)
        PSD (cnt/rtHz)   TF Mag    Phase

REFL33I 15.7565          1.5298e-2 -109.727
REFL33Q  0.171648        1.6310e-4 -141.73
REFL55I 16.2834          1.5809e-2 -109.672
REFL55Q  0.634096        6.1012e-4 -143.169

These measurements are saved in the XML files (for DTT) in
/cvs/cds/caltech/users/koji/130521/
as
130521_MICH_EXC.xml and 130521_PRCL_EXC.xml

As the actuator of the PRM/ITMX/ITMY are {19.6, 4.70, 4.66}/f^2 nm/cnt, the optical gains were calculated from the TF measurements.

MICH excitation (ITMX -1, ITMY +1)
        OPTICAL GAIN
(cnt/m)
REFL33I 4.0e9
REFL33Q 7.9e8
REFL55I 5.9e8
REFL55Q 6.5e9

PRCL excitation (PRM +1)
        OPTICAL GAIN

REFL33I 3.1e11
REFL33Q 3.3e9
REFL55I 3.2e11
REFL55Q 1.2e10

These should be compared with the measurement by the script and we get more information from the script (like AS55, REFL11)

  8610   Tue May 21 23:29:57 2013 ManasaUpdateGreen LockingXend Green aligned

X-green and PSL green have been aligned so that they interfere at the beat PD for X.

I haven't scanned the X-end NPRO temperature to find the beat note. I found the earlier elog when this was done (elog 6851) and will use those temperatures to start with.

  8609   Tue May 21 18:22:18 2013 JenneUpdateLSCSensing matrix scripts modified to include actuator calibration

The PRMI sensing matrix scripts have been modified to output a sensing matrix which is calibrated into units of counts/meter.

To run, you should just need to run .../scripts/LSC/runPRMI_SENS.py . 

If it looks like the drive amplitude is not large enough (no nice peak in the photodiode signals), you can increase the drive amplitude, which is line 21 in runPRMI_SENS.py  

  8608   Tue May 21 18:18:28 2013 JamieUpdateComputer Scripts / ProgramsnetGPIB stuff update/modernized/cleanedup/improved

I did a bunch of cleanup work on the netGPIB stuff:

  • Removed extensions from all executable scripts (executables should not have language extensions)
  • fixed execution permissions on executables and modules
  • committed HP8590.py and HP3563A.py instrument modules, which were there but not included in the svn
  • committed NWAG4395A (was AG4395A_Run.py) to svn, and removed old "custom" copies (bad people!)
  • cleaned up, modernized, and fixed the netgpibdata program
  • removed plotting from netgpibdata, since it was only available for one instrument, there's already a separate program to handle it, and it's just plotting the saved data anyway
  • added a netgpibcmd program for sending basic commands to instruments.
  • added a README

Probably the most noticeable change is removing the extensions from the executables.   There seems to be this bad habit around here of adding extensions to executables.  It doesn't matter to the person running the program what language it was written in, so don't add extensions.  It only matters for libraries.

  8607   Tue May 21 18:18:23 2013 ManasaUpdateGreen LockingXend Green aligned

X arm aligned to green.

Aligned the X arm to IR.
Used steering mirrors to align the X end green to the X arm while remaining locked for IR. X arm locks to green stably with GTRX at the PSL table measuring 235uW and corresponds to 2560counts in C!:ALS-TRX_OUT.

Next
1. PSL green alignment.
2. Search for beat note.
3. Resurrect ALS for X arm.

  8606   Tue May 21 17:03:45 2013 SteveUpdateendtable upgradeenclosure tops are sealed

Quote:

 

 I'm planning to remove the ETMY optical table enclosure and move it over to CES Shop 8am Thursday morning.

We'll install spring loaded lathes, hooks and quick release pins.

The bridge will be reinforced with steel plate to support release pins on posts.

There will be an other cut out for cable feedtrough as it is shown on elog #8472

Let me know if this timing does not fit your work.

 The bridge support posts were shimmed today. Surgical tubing 402R - o - rings were glued togeather with " instant krazy glue "

Atm2  Carey CH-3540 latches are compressed ~2.5 mm in the clamped position.

Atm3 is showing the captured quick release pin in the steel reinforced bridge that is supported by the post. It works great. The post screw is sealed by o-ring. The quick-pin is sealed by an epoxy attached copper cap.

Atm4 Enclosure is on it's back. Bottom o-ring can be seen. The hole reinforced bridge structure is visible.

Now I'm working on the window connection to the chamber. I'm very close leak checking this box.

In case of leaking around the top tubing seals we have two options:

a, cut down on the cover rim by 0.040"  or b, increase tubing diameter

Attachment 1: ETMYoptable.jpg
ETMYoptable.jpg
Attachment 2: surgtubclamps.jpg
surgtubclamps.jpg
Attachment 3: quickrelease.jpg
quickrelease.jpg
Attachment 4: reinforcbridge.jpg
reinforcbridge.jpg
  8605   Tue May 21 16:23:06 2013 ManasaUpdateGeneral40MARS wireless network problem RETURNS

Quote:

Here's an example of the total horribleness of what's happening right now:

controls@rossa:~ 0$ ping 192.168.113.222
PING 192.168.113.222 (192.168.113.222) 56(84) bytes of data.
From 192.168.113.215 icmp_seq=2 Destination Host Unreachable
From 192.168.113.215 icmp_seq=3 Destination Host Unreachable
From 192.168.113.215 icmp_seq=4 Destination Host Unreachable
From 192.168.113.215 icmp_seq=5 Destination Host Unreachable
From 192.168.113.215 icmp_seq=6 Destination Host Unreachable
From 192.168.113.215 icmp_seq=7 Destination Host Unreachable
From 192.168.113.215 icmp_seq=9 Destination Host Unreachable
From 192.168.113.215 icmp_seq=10 Destination Host Unreachable
From 192.168.113.215 icmp_seq=11 Destination Host Unreachable
64 bytes from 192.168.113.222: icmp_seq=12 ttl=64 time=10341 ms
64 bytes from 192.168.113.222: icmp_seq=13 ttl=64 time=10335 ms
^C
--- 192.168.113.222 ping statistics ---
35 packets transmitted, 2 received, +9 errors, 94% packet loss, time 34021ms
rtt min/avg/max/mdev = 10335.309/10338.322/10341.336/4.406 ms, pipe 11
controls@rossa:~ 0$ 

Note that 10 SECOND round trip time and 94% packet loss.  That's just beyond stupid.  I have no idea what's going on.

This has not been fixed!

Temporary solution: I ssh'd to nodus from the 40m wifi network and was able to connect to the FE machines.This works but the bandwidth is limited this way as expected.

40m MARS network needs to be fixed.

  8604   Tue May 21 14:50:52 2013 Max HortonUpdate Importing New Code

There was an issue with running the new summary pages, because laldetchar was not included (the website I used for instructions doesn't mention that it is needed for the summary pages).  I figured out how to include it with help from Duncan.  There appear to be other needed dependencies, though.  I have emailed Duncan to ask how these are imported into the code base.  I am making a list of all the packages / dependencies that I needed that weren't included on the website, so this will be easier if/when it has to be done again.

  8603   Tue May 21 14:48:08 2013 JenneUpdateLSCPRMI sensing matrix - not high quality data

The PRMI sensing matrix, as measured last Thursday, in a more readable format:

EDIT: DON'T Look at this yet!  I forgot to calibrate it!  Please hold.....

            PRCL          MICH        
AS55_I      1.228E-01     5.476E-03    
AS55_Q      1.547E-01     1.345E-01    
REFL11_I    9.946E+03     8.106E+01    
REFL11_Q    2.346E+03     2.707E+01    
REFL33_I    9.639E+01     8.717E-01    
REFL33_Q    9.707E-01     6.626E-02    
REFL55_I    1.040E+02     8.464E-01    
REFL55_Q    2.018E+00     5.803E-01

 

Okay, Calibrated, but forgot to include loop compensation (since notches didn't exist yet):

Sensing Matrix, units = cts/meter
 
            MICH          PRCL        
AS55_I      5.024E+08     9.418E+07    
AS55_Q      6.328E+08     2.313E+09    
REFL11_I    4.068E+13     1.394E+12    
REFL11_Q    9.594E+12     4.656E+11    
REFL33_I    3.942E+11     1.499E+10    
REFL33_Q    3.970E+09     1.140E+09    
REFL55_I    4.253E+11     1.456E+10    
REFL55_Q    8.252E+09     9.981E+09

 

  8602   Mon May 20 18:50:22 2013 JenneUpdateLSCKiwamu's sensing matrix measurement script revived

So that I don't have to do loop compensation every time I measure a sensing matrix, I have put (back) in notches into FM10 of all the LSC filter banks, except MC2.  

MICH already had this notch, PRCL and CARM both had it, although it was mislabeled in the filter title as "Notch410" rather than the truth, which is "Notch628". 

The XARM and YARM filter banks were full, since we have not (in those filter banks) combined all of the resonant gains - 3.2Hz, 16Hz, 24Hz - into one module.  I took out a CLP3000 (  cheby1('LowPass",2,3,3000)gain(1.41254)  ) in each of those filter banks, and put in the notch.

I also have changed the band pass filters in the LSC-Lockin#_SIG filter banks to match this new drive frequency.

  8601   Mon May 20 18:47:47 2013 KojiUpdateLSCPRMI sensing matrix - not high quality data

For now forget about the demodulation phase and assume all of the ports are independent.
I want to know the numbers in the following format.

          PRCL     MICH   (unit: cnt/m)
REFL11I:  x.xxxEx x.xxxEx
REFL11Q:  x.xxxEx x.xxxEx
REFL33I:  x.xxxEx x.xxxEx
REFL33Q:  x.xxxEx x.xxxEx
REFL55I:  x.xxxEx x.xxxEx
REFL55Q:  x.xxxEx x.xxxEx
REFL165I: N/A     N/A
REFL165Q: N/A     N/A
AS55I:    x.xxxEx x.xxxEx
AS55Q:    x.xxxEx x.xxxEx

If you really want to resolve the TF phase difference between the I and Q  demod-signals,
you need to look at the transfer functions between the excitation and these ports.
We can't understand what is happening only from the single point measurement.

  8600   Mon May 20 17:49:36 2013 JenneUpdateLSCPRMI sensing matrix - not high quality data

Just so we have some numbers, I did a by-hand analysis of the PRMI sensing matrix numbers I posted here in the elog the other day.  This analysis is ignoring the error bar data.

For each sensor (PD_I or PD_Q), I do loop compensation, since these measurements were taken fairly close to the UGFs of the loops, and notches were not in use at the drive frequency.  To do the loop compensation, I multiply the complex value (lockin_I + i*lockin_Q) by (1-G), where G is the (complex) open loop gain of the degree of freedom I'm shaking.

 When I'm shaking a single degree of freedom (ex. shaking the PRM to get PRCL information), for each PD_I or PD_Q, we get 2 numbers, the lockin_I and lockin_Q values.    I check the phase between the lockin_I and lockin_Q values, since that phase (after loop compensation) should be either 0 or 180, and if it is not, something is wrong. 

Of the 16 sensors I measure (where PD_I and PD_Q count as 2 sensors), 11 sensors had phases more than 20 degrees away from either 0 or 180.  This is not good, and indicates that something is wrong with my measurement.  I suspect that I may not be driving hard enough -  I was using an amplitude 4x smaller than the previous value.  Next time the PRMI is locked, I will turn on the drive oscillation, and ensure that I can see the line in all of the PD signals.

The results of my quickie analysis script:

Bad REFL11_I_MICH phase!  Phase is -82.0185 degrees!
Bad REFL11_Q_MICH phase!  Phase is -35.9697 degrees!
Bad REFL33_I_MICH phase!  Phase is -134.952 degrees!
Bad REFL55_I_MICH phase!  Phase is -79.7997 degrees!
Bad AS55_I_PRCL phase!  Phase is -142.6016 degrees!
Bad AS55_Q_PRCL phase!  Phase is 90.6194 degrees!
Bad REFL11_I_PRCL phase!  Phase is 52.471 degrees!
Bad REFL11_Q_PRCL phase!  Phase is 52.2324 degrees!
Bad REFL33_I_PRCL phase!  Phase is 52.909 degrees!
Bad REFL33_Q_PRCL phase!  Phase is 25.14 degrees!
Bad REFL55_I_PRCL phase!  Phase is 52.8113 degrees!

Sensing Matrix, calculated even though most of the measurement data isn't any good:
AS55: MICH = 0.13502, -1.6122deg.  PRCL = 0.14993, -2.245deg
REFL11: MICH = 29.6373, -2.6365deg.  PRCL = 7376.3206, -2.9098deg
REFL33: MICH = 0.35649, -2.9633deg.  PRCL = 69.5133, -3.1302deg
REFL55: MICH = 0.62084, -2.0261deg.  PRCL = 75.0214, 3.1176deg

Attachment 1: PRMIsensMatQuickAnalysis.m.gz
  8599   Fri May 17 19:56:52 2013 KojiSummaryCDSWeird DAC bit flipping at half integer output values

Let me make a complimentary comment on this effect.

Because of this oscillation feature, we have a 32kHz peak in the DAC spectrum rather than a 64kHz peak.

For advanced LIGO, the universal AI (D070081) was made to have 3rd-order 10kHz LPF with 64kHz notch.
If we have a higher peak at 32kHz (where the rejection is not enough) than at 64kHz, the filter does not provide
enough filtering of the DAC artifacts.

For the 40m, the original filter had the cut off of 7kHz as the sampling rate was 16kHz.
If we want to extend the frequency range by 4times, the correspoding cut off should be 28kHz.
The rejection is again not enough at 32kHz.

If this peak is an avoidable feature by using simple sample&hold the peak freq is pushed up to
64kHz and we can use the AI filters as planned.

  8598   Fri May 17 18:58:58 2013 Jamie, KojiSummaryCDSWeird DAC bit flipping at half integer output values

While looking at the DAC anti-imaging filters, Koji noticed an odd feature of the DAC output:

sweep.pdf

What you see here is 16kHz double data from a model right before the DAC part ('C1:SUS-PRM_ULCOIL_OUT', blue), and the full 64kHz int data sent to the physical DAC as reported by the IOP ('C1:X02-MDAC0_TP_CH0', green).  The balls are the actual sample values (as expected there are four green balls for every blue).  The output data is being ramped continuously between 0 and 1.

As the output data crosses the half-count level, the integer DAC output oscillates continuously at every 64kHz sample between the bounding integer values (in this case 0 and 1).

Here's the data as we hold the output continuously at the half-count level; the integer DAC output just oscillates continuously:

const.pdf

After some probing I found that the oscillation happens between [-0.003 +0.004] of the half-count level.

The result of this is a fairly strong 32 kHz line in the DAC analog output.

We looked in the controller.c and couldn't identify anything that would be doing this.  This is the output procedure as I can see it (controller.c lines): 

  1. The double from the model is passed to the IOP
  2. The IOP applies a sample-and-hold or zero-pad if the model is running at a slower speed than the IOP (1799)
  3. The data is then anti-image filtered (1801)
  4. A half-integer is added/subtracted before casting such that the cast is a round instead of a floor (1817)
  5. The data double is cast to an int (1819)
  6. The data is written to the DAC (1873)

There's nothing there that would indicate this sort of bit flipping.

  8597   Fri May 17 18:24:04 2013 AnnalisaUpdate40m upgradingETMY - progress

I aligned the green beam into the Faraday. I needed an HWP to have the right polarization for the light entering the Faraday itself.

I tried to dump as much beams as possible with razor dumps, but eventually I had to use some "temporary solutions" for higher beams, because I didn't find the right mounts for razor dumps.

I measured the beam waist after the Faraday with the beam scan. Analysis and MM calculation to follow.

  8596   Fri May 17 16:06:14 2013 ranaUpdate40m upgradingETMY op table disabled

 

 TODO:

  1. We need to replace all of the floppy anodized Al dumps with clean razor blade dumps on stiff mounts. BOTH of the rejected ports of the 1064 FI need some kind of custom dump.
  2. All of the leakthrough beams of the HR mirrors also need razor dumps. A good rule of thumb is that your first notion of how to implement the beam dump is NOT good enough.
  3. The whole lens / modematching situation for the 1064 and 532 paths will have to be redone so as to put the beam waists inside the Faraday crystal (NOT outside). The beam waist in the 4.7 mm diameter Faraday should be ~0.3-0.4 mm.
  4. The efficiency that we got for the doubling shows that we don't need the cylindrical lenses - they are nice, but not needed to get 90% of the max power.
  5. The lenses between the 1064 FI and the doubler should be put onto a base that can be used to adjust the lens position for MM optimization. Nothing fancy, just something slideable.
  6. For this iteration of the table, we can do as Annalisa has written so as to get the green MM lenses ordered ASAP. After next week we can come up with a new plan before dismantling the EX table.
  8595   Fri May 17 15:38:51 2013 SteveUpdate40m upgradingETMY enclosure is on the way back

 

 It  will arrive around 10 am Monday morning.

 

  8594   Fri May 17 00:32:32 2013 AnnalisaUpdate40m upgradingETMY - progress

[Rana, Annalisa] 

 GREEN

 The alignment for the green has been improved, so that we have much more green power.

The first lens position along the IR path has been changed in way to have the beam waist at the center of the first Faraday. In this way we had about 91% of the input power out from it.

The two cylindrical lenses which were used to correct the ellipticity of the beam have been replaced by a single lens. Its focal length is intermediate between the focal lengths of the two cylindrical. 

Moving the position of the lens before the doubler crystal and improving the alignment we got about 1mW of green light (0.35% of the incoming IR beam).

TO DO

 

After aligning the green beam through the second Faraday, the beam waist of the outgoing beam has to be measured and the mode matching calculation has to be done to choose the two MM lenses. Then the steering mirrors will be placed to send the beam into the arm.

Attachment 1: IMG_0536.JPG
IMG_0536.JPG
  8593   Thu May 16 23:48:39 2013 JenneUpdateLSCKiwamu's sensing matrix measurement script revived

Koji locked the PRMI for me, and I took some data.  I haven't finished figuring out what to do with it / writing a processing script.

Here is the data, in a python dictionary (not for you to read, but so that it's here and you can use it later if you want).

{'AS55_Q': [['ErrorBarData0', '-1.60826e-05', '0.000154774'], ['ErrorBarData1', '-1.61949e-05', '-9.69142e-05'], ['ITMs', '-0.134432', '0.00240338'], ['PRM', '0.0525864', '0.145516']], 'REFL55_Q': [['ErrorBarData0', '-0.00088166', '-0.00294315'], ['ErrorBarData1', '0.00298076', '-0.000466507'], ['ITMs', '-0.573825', '-0.0865747'], ['PRM', '1.94537', '0.534968']], 'REFL33_Q': [['ErrorBarData0', '0.000868208', '0.000785702'], ['ErrorBarData1', '-0.00136268', '-0.000288528'], ['ITMs', '-0.0653009', '-0.0112035'], ['PRM', '0.875275', '0.419765']], 'REFL11_I': [['ErrorBarData0', '-0.147347', '0.136075'], ['ErrorBarData1', '0.351823', '0.160556'], ['ITMs', '-12.0739', '-80.1513'], ['PRM', '6991.11', '7073.74']], 'REFL33_I': [['ErrorBarData0', '-0.00100624', '0.00134366'], ['ErrorBarData1', '0.00373581', '0.000783243'], ['ITMs', '-0.399404', '-0.774793'], ['PRM', '67.4138', '68.8886']], 'REFL11_Q': [['ErrorBarData0', '-0.0173368', '0.0141987'], ['ErrorBarData1', '0.100048', '0.0882165'], ['ITMs', '6.46585', '-26.2841'], ['PRM', '1653.42', '1663.96']], 'AS55_I': [['ErrorBarData0', '-1.87626e-05', '2.24596e-05'], ['ErrorBarData1', '-5.46466e-05', '-2.96552e-07'], ['ITMs', '-0.00531763', '0.00130579'], ['PRM', '-0.100501', '-0.0706334']], 'REFL55_I': [['ErrorBarData0', '-0.000774208', '-5.32631e-05'], ['ErrorBarData1', '0.00347621', '0.0025103'], ['ITMs', '-0.115633', '-0.83847'], ['PRM', '72.8058', '74.2347']]}

The structure is that each sensor has some "error bar" measurements, when there was no drive to any optics (I, then Q of the lockin), and then response to different optics' drives (waiting 20sec after turning on the oscillator before making a measurement, since the lockin has 0.1Hz lowpasses.  ).

The amplitude that Kiwamu had of 4000 cts in the LSC lockin was fine for MICH, but made PRCL unlock, so this data was taken with an amplitude of 1000 counts, at a frequency 283.1030 Hz. 

Since this is only barely above the UGF for both MICH and PRCL loops, I also have OLTF information at 283Hz from DTT:  PRCL mag = -1.05264 dB, phase = 24.6933 deg, MICH mag = -8.50951 dB, phase = 31.3948 deg.

I have started writing a script SensMatAnalysis.py in the scripts/LSC directory to do the analysis, but after having talked to Koji, I need to do more thinking to make sure I know what I'm doing.  Stay tuned for actual analysis later.

  8592   Thu May 16 22:03:16 2013 KojiConfigurationLSCY Green BBPD returned to the PSL table

I borrowed the GTRY BBPD  for the REFL165 trial before.

Now the PD is back on the PSL table.

The PD is intentionally misaligned so that anyone can find it is not aligned.

  8591   Thu May 16 11:50:25 2013 KojiConfigurationElectronicsMeasurement and empirical models of the AI board TFs

Yesterday, I pulled out the AI board for the PRM/BS SUSs. (After the investigation it was restored)

Contrary to our expectation, the board D000186 was not Rev. A but Rev. B.

According to Jay's note in D000186 (for Rev.D), the differences of the Revs are as follows

Rev.A: Initial Release (Analog Biquad version, 4dB 4th order elliptic with notches)
Rev.B: Filter implemented by Freq Devices chip
Rev.C: Differential input version with better RF filtering
Rev.D: 3rd order 0.5dB ripple Cheby with notches at 16K&32K, DB25 input version


I went to the WB EE shop and found bunch of AI filter modules. At least I found one Rev.A and six Rev.D.
I found at least one Rev. C.

I took Rev.A and Rev. D to see the difference of the transfer functions.
Rev.A has more ripple but steeper roll-off. Rev. D is flater at the pass band with slower roll-off.
Rev.D has more phase lag, but it will be fine once the entire frequency response is shifted to x4 high frequency.
The notch frequency of the Rev. D looked right.

I made the empirical pole/zero modeling of the transfer functions.
The LISO models are attached as the ZIP file.
I faced an unexplainable phase behavior at around one the notches for Rev.A.
This may suggest there could have been internal saturation is the stage during the sweep.

More importantly, Rev. D has differential inputs although the connector formfactor is different from the current 40pin IDC.
In fact we should not use Rev.A or Rev.B as they have single end inputs.
Currently the inputs of the AI's for the SUSs are single ended while the DACs are differential.
This means that
1) We waste a half of the DAC range.
2) The negative outputs of the DACs are short-circuited. OMG
3) The ground level fluctuation between the DAC and the SUS rack fluctuates the actual actuation voltage.

Now I am looking at the noise performance of the filters as well as the DAC output noise and range.
I hope we can use Rev.D by replacing the connector heads as this will remove many of the problems we currently have.

Attachment 1: D000186AD_TF.pdf
D000186AD_TF.pdf
Attachment 2: D000186AD_TF.zip
  8590   Thu May 16 08:32:05 2013 SteveUpdate40m upgradingETMY op table disabled

 

All ETMY optical table electronics- lasers-pds turned off, disconnected in order to remove enclosure.

linguaa.jpg

  8589   Thu May 16 04:46:37 2013 JenneUpdateLSCKiwamu's sensing matrix measurement script revived

Kiwamu had an old set of scripts for measuring the sensing matrices, but they were hidden away in ..../scripts/general/kiwamuscripts/pyplant . I have moved them to a more useful place, and updated them.

The useful scripts (the main one is SensResp.py, and the PRMI-specific one, runPRMI_SENS.py, which calls SensResp.py) have been moved to .../scripts/LSC .  I have also created a folder within the LSC scripts folder called SensMatData for the data.

The 2 big changes to Kiwamu's scripts:  The ezca library that he was calling wasn't working.  I switched it over to using the one that Yuta wrote, in ..../scripts/pylibs.  Also, Kiwamu's script was written back during a time where we must have only had one total lockin for the whole LSC model.  Now we have one per PD in the input matrix.  This meant that several of his channel names were wrong.  I have fixed this, and also made it measure all the sensors at once using tdsread of the _OUT16 channels (the OUT16's have some AA action, other EPICS channels don't).

So, now (after you're locked), it shakes one "mirror" (the ITMs are shaken differentially at the same time, as one "mirror"), and reads out all of the RF PD lockin values.  Then it moves to the next mirror.  (For the PRMI case, there are only 2 "mirrors":  The ITM set and the PRM.)  All of the information is stored in a dictionary, which is written to a text file. 

The format of the dictionary is:

{ OPTIC_1: [Photodiode_1, Lockin_I, Lockin_Q], [Photodiode_2, Lockin_I, Lockin_Q], OPTIC_2: [Photodiode_1, Lockin_I, Lockin_Q], [Photodiode_2, Lockin_I, Lockin_Q] }

At this point, I am too tired to actually do a measurement, although next time the PRMI is locked, we should just have to run the runPRMI_SENS.py, and look at the data.  I'm also not quite sure how to extract the information from a dictionary after it has been written to a text file.  This may not be a good way to store data, and I'll ask Jamie about it tomorrow.

OTHER NOTES:

* I need to set up another iteration of the sensing matrix measurement with no drive, measuring several times, to get an estimate of the error in a single measurement.

 

* I had the PRMI locked on AS55Q/REFL33I for more than half an hour.  Then the MC started unlocking semi-regularly.  Seismic was good except for one EQ ~2 hours ago.  After the earthquake (unlocked MC, but no tripped optics), the MC has remained locked.

* The LSC Lockin Overview screen does not click-through to the _SIG individual screens.  We need to fix the path to these screens.

* All of the _SIG filters are band passes around 285 Hz, but the names of the filters all say 238Hz.  I need to fix all 27 of these.

* We can perhaps change the LSCoffsets script someday to use tdsread a few times, and average the results (since the PDs don't have lowpass filters, and we're measuring the offset of the IN1 location, not the OUT).  This way we can hopefully measure all the PDs at once and speed up the script, without having failed tdsavg runs.

ELOG V3.1.3-