40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log, Page 290 of 344  Not logged in ELOG logo
ID Date Author Type Category Subjectup
  13181   Thu Aug 10 09:10:55 2017 steveUpdateGeneraldataviewer is recovering

It can look back 7 days trends now. There is still no vacuum channels. I can bring back the channels through the restore directory, but there are no data.

Attachment 1: 7dm.png
7dm.png
  5049   Wed Jul 27 15:49:13 2011 jamieConfigurationCDSdataviewer now working on pianosa

Not exactly sure what the problem was, but I updated to the head of the SVN and rebuilt and it seems to be working fine now.

  1652   Thu Jun 4 16:54:19 2009 peteUpdateLockingdaytime DD handoff

I played with the DD handoff during the day.  The DRM dark port was flickering like a candle flame in Dracula's castle.  The demod offsets for the handoff signals looked fine.  After MICH handoff, the MICH_CTRL started to get unstable at some low frequency, maybe 3 Hz (I didn't measure).  So I increased the MICH gain from 0.1 to 0.17 and it settled down.  PRC and SRC went fine.  Then the DD_handoff script raised the MICH gain to 0.7, and an instability started to grow in MICH_CTRL (at some higher frequency).  I decreased the MICH gain from 0.7 to 0.5, and it settled down and stayed stable.

  1658   Fri Jun 5 17:22:55 2009 peteUpdateLockingdaytime locking

After fixing the tp problem, I tried locking again.  Grabbing and DD handoff, no problem.  Died earlier than last night, handing off CARM to REFL_DC, around arm power of 4 or so.  Seems to happen after turning off the moving zero, Rob says it might be touchy in daytime.

  2092   Wed Oct 14 16:59:37 2009 robUpdateLockingdaytime locking

The IFO can now be locked during the daytime.  Well, it's locked now.

  2093   Wed Oct 14 23:02:41 2009 ranaUpdateLockingdaytime locking

This is huge.    Five hours of lock only interrupted by intentional break from transfer function abuse.

Attachment 1: a.png
a.png
  4606   Tue May 3 05:32:04 2011 kiwamuUpdateLSCdaytime tasks

Daytime tasks :

 - PRM & BS oplev (Steve)

 - LSC binary outputs (Joe/Jamie)

 - installation of the REFL55 RFPD (Suresh/Jamie)

 - Adjustment of demodulation phases (Kiwamu)

 - Bounce-Roll filters on BS and PRM (Suresh/Joe)

 - Suspension diagnostic using the free-swinging spectra (Leo)

 - PMC alignment (Jenne/Koji)

  4607   Tue May 3 10:21:25 2011 KojiUpdateLSCdaytime tasks

I think the installation of the PD DC signals are quite important. What to do
1) Connect the DC signals to the right top whitening board (be aware that there may be the modification of the whitening circuit).
2) Reconfigure the LSC model such that the DC signal is passed to the right channels (modify the left top part of the model)

Quote:

Daytime tasks :

 - PRM & BS oplev (Steve)

 - LSC binary outputs (Joe/Jamie)

 - installation of the REFL55 RFPD (Suresh/Jamie)

 - Adjustment of demodulation phases (Kiwamu)

 - Bounce-Roll filters on BS and PRM (Suresh/Joe)

 - Suspension diagnostic using the free-swinging spectra (Leo)

 - PMC alignment (Jenne/Koji)

 

  4610   Tue May 3 11:49:03 2011 KojiUpdateLSCdaytime tasks

Done. C1:PSL-PMC_PMCTRANSPD was improved from ~0.75 to 0.87.

Quote:

- PMC alignment (Jenne/Koji)

 

  6412   Wed Mar 14 05:26:39 2012 interferomter tack forceUpdateGeneraldaytime tasks

The following tasks need to be done in the daytime tomorrow.

  • Hook up the DC output of the Y green BBPD on the PSL table to an ADC channel (Jamie / Steve)
  • Install fancy suspension matrices on PRM and ITMX [#6365] (Jenne)
  • Check if the REFL165 RFPD is healthy or not (Suresh / Koji)
    • According to a simulation the REFL165 demod signal should show similar amount of the signal to that of REFL33.
    • But right now it is showing super tiny signals [#6403]
  6416   Wed Mar 14 14:09:01 2012 interferomter tack forceUpdateGeneraldaytime tasks

Quote:

The following tasks need to be done in the daytime tomorrow.

  • Hook up the DC output of the Y green BBPD on the PSL table to an ADC channel (Jamie / Steve)
  • Install fancy suspension matrices on PRM and ITMX [#6365] (Jenne)
  • Check if the REFL165 RFPD is healthy or not (Suresh / Koji)
    • According to a simulation the REFL165 demod signal should show similar amount of the signal to that of REFL33.
    • But right now it is showing super tiny signals [#6403]

 For ITMX, I used the values from the conlog:

2011/08/12,20:10:12 utc 'C1:SUS[-_]ITMX[-_]INMATRIX'
These are the latest values in the conlog that aren't the basic matricies.  Even though we did a round of diagonalization in Sept, and the 
matricies are saved in a .mat file, it doesn't look like we used the ITMX matrix from that time.

For PRM, I used the matricies that were saved in InputMatricies_16Sept2011.mat, in the peakFit folder, since I couldn't find anything in the Conlog other than the basic matricies.

 

UPDATE:  I didn't actually count the number of oscillations until the optics were damped, so I don't have an actual number for the Q, but I feel good about the damping, after having kicked POS of both ITMX and PRM and watching the sensors.

  4142   Wed Jan 12 02:41:19 2011 kiwamuUpdateGeneraldaytime tasks for tomorrow

[Rana, Kiwamu]

Here is the list for the daytime tasks of tomorrow, Jan. 12th.

The daytime task is a work basically to be done or quitted before the sun goes down.

Along with the tasks, we roughly assigned the people who are responsible for it.

The tasks below are basically separated from each other, so we can work in parallel.

 

 

--- 1.  LSC analog interface check (Joe/Koji)

   * check whitening filter

   * demodulation board check

    * check ADC connections

 

--- 2.  MC2 coil Dewhitening (Joe)

    * fix binary outputs.

    * FM9 must be the trigger of the binary outputs instead of FM10.

 

--- 3. 11MHz modulation depth (Kiwamu)

   * investigate why the depth is so low

 

--- 4. PEM DAQ name issue (Jenne)

   * change the name of seismic channels properly so that we can deal with the calibrated stuff

 

--- 5. phase adjustment for MC-PDH locking (Suresh)

 

--- 6. medm screens for C1LSC ()

    * make screens

 

 

 

  14492   Thu Mar 21 18:09:36 2019 KojiUpdateCDSdb file preparation for acromag c1susaux

I have updated the google doc spreadsheet to indicate the required action for the new dbfile generation.

There are three types of actions:

1. COPY - Just duplicate the old EPICS db entry. This is for soft channels, calc channels.
2. DELETE - Delete the entry for some physical channels that will not be implemented on Acromag (oplev, dewhitening mon, AI monitor, etc)
3. REPLACE - For the physical channels, we want to replace the port names.

The blue part of the spreadsheet indicates the action for each channel. If it is a physical channel, the assigned module and the channel are indicated there. What we still want to do is to use the these information for generating the port name which looks like "@asynMask(C1VAC_XT1221A_ADC 1 -16)MODBUS_DATA".

The links to the spreadsheets can be found on 40m wiki: https://wiki-40m.ligo.caltech.edu/CDS/SlowControls/c1susaux

Attachment 1: Screen_Shot_2019-03-21_at_18.06.53.png
Screen_Shot_2019-03-21_at_18.06.53.png
  14462   Fri Feb 15 21:15:42 2019 gautamUpdateVACdd backup of c1vac made
  1. Connected one of the solid-state drives to c1vac. It was /dev/sdb.
  2. Formatted the drive using sudo mkfs -t ext4 /dev/sdb
  3.  Mounted it as /mnt/backup using sudo mount /dev/sdb /mnt/backup
  4. Started a tmux session for the dd, called DDbackup
  5. Started the dd backup using  sudo dd if=/dev/sda of=/dev/sdb bs=64K conv=noerror,sync
  6. Backup completed in 719 seconds: need to test if it works...
controls@c1vac:~$ sudo dd if=/dev/sda of=/dev/sdb bs=64K conv=noerror,sync
[sudo] password for controls: 
^C283422+0 records in
283422+0 records out
18574344192 bytes (19 GB) copied, 719.699 s, 25.8 MB/s
Quote:
 
  • Generate a bootable backup hard drive for c1vac, which could be swapped in on a short time scale after a failure.
  9937   Fri May 9 11:23:11 2014 steveUpdateGreen Lockingdecreased X green light power

Green light power decreased from 3 mW to 1 mW at the ETMX-ISCT shutter. More later.

  6300   Tue Feb 21 16:10:29 2012 kiwamuUpdateIOOdegradation in input PZT1

PZT1, the one with Koji's custom mid-HV driver (#5447), is getting degraded.

The movable range in the pitch direction became narrower than what it used to be (maybe a factor of 3 estimated by looking at the beam spots).

I think we should raise the priority level of the active TTs for the next vent.

 

I have been having a feeling that the PZT1 response is getting smaller since the end of the last year, but now I am confident

because I could see the difference between the movable ranges of Yaw and Pitch, and they used to have approximately the same amount of the movable ranges.

Right now this is not a serious issue as the beam pointing determined by the MC alignment is so good that the Pitch range doesn't rail.

I won't be surprised if it becomes completely immovable in 3 month.

  5268   Fri Aug 19 09:14:56 2011 steveUpdateIOOdegrading laser power at atm

Light into the MC is 20 mW at atm, MC_Transmitted ~10 MW = 400 count

The PMC_T is OK but something else is drifting.

Attachment 1: power@atm.jpg
power@atm.jpg
  6120   Wed Dec 14 14:40:53 2011 steveUpdateGreen Lockingdelay line bnc cable specs

The existingly used used Pasternack Enterprices RG58 C/U cable lenght ~ 140 ft and the specs are here at Atm1

 

Atm2 The performance grade RG58-P coaxial cable specs.

Attachment 1: rg58cu.jpg
rg58cu.jpg
Attachment 2: RG58-P.pdf
RG58-P.pdf
  15174   Wed Jan 29 12:29:33 2020 shrutiUpdateGeneraldelay line frequency discriminator for PM

 Today I began working on a TF measurement based on the delay line frequency discriminator setup in elog 4254 using a single mixer (without the 'I' and 'Q' readout).

For this, I re-organised the setup for the PLL measurement of the transfer function (elog 15148), increasing the HEPA for the initial changes while the PSL door was open, and then reverting it back to ~30%:

  • I removed the 20dB coupler and connected the splitter directly after the amplifer to split the beat note signal into two coaxial cables one of which was ~1.5m longer than the other
  • The recombined signals were combined in a mixer outside the PSL enclosure. I also replaced the 1.9 MHz LPF with a 5 MHz LPF.
  • I used an SR 560 to amplify the signal after the LPF.

With the above setup the power that was seen at each channel of the delay line was <1dBm, which is not ideal for the any of the available mixers.

After the group meeting, I changed the amplifer to ZHL-3A (that is near the beat mouth) instead of a ZFL-500HLN because it had a higher gain (~28dB as opposed to ~19dB of the latter). The power seen at each of the delay line channels is over 5.5 dBm. This is consistent with the estimation 0 dBm beat -> -20 dBm after 20dB coupler -> 8 dBm after amplifier -> 5 dBm after splitter with insertion loss of 3 dB.

Is this sufficient enough for the mixer to work? In Attachment 1: A shows the mixer output (point B in Attachment 2) when the IMC is locked, in B the IMC is unlocked at the middle of the spectrum, and each of the dips show the DC voltage being sent to the PSL temperature servo being decreased by 0.01 V.

Gautam pointed me to the location of a few other RF amplifiers (ZHL-32A+, ZHL-1A) which don't possess a higher gain but can be used without disrupting the ALS related work (I was told).

For shorter duration changes that I made later, I opened and closed the PSL enclosure doors without changing the HEPA.

Attachment 2 shows the current setup as is, but I might add a PSL servo tomorrow to stabilise its frequency corresponding to a null mixer output without driving anything else.

Attachment 1: 20200128.png
20200128.png
Attachment 2: IMG_BB01C068495A-1.jpeg
IMG_BB01C068495A-1.jpeg
  15177   Thu Jan 30 15:24:10 2020 ?UpdateGeneraldelay line frequency discriminator for PM

yes, its fine to use this with a level 3 or level 7 mixer; let's see some PM transfer functions !

Quote:

Is this sufficient enough for the mixer to work?

  15180   Thu Jan 30 22:02:42 2020 shrutiUpdateGeneraldelay line frequency discriminator for PM

I could not find any level 3 mixers, but by adjusting the beat frequency the power in each of the delay line channels rose to almost 6.5 dBm.

In short: Delay line seems to work

Things I did earlier today:

  1. Played with the slow servo on the FSS screen, but then reset the parameters to what was there before (Later found out that this was to lock the PSL freq to the IMC when the IMC power is significant.)
  2. Connected the AG 4395A to the X PZT
  3. Closed the PSL shutter

Transfer function measurement: (Refer Attachment 1)

Everything about the setup remained as I had left it earlier: described in elog 15174

except

  • SR560 gain set to 10, DC coupled
  • DC block at channel A of Agilent (The measurement was A/R)

I did not use a slow servo, but took individual sweeps adjusting the PSL temperature each time to bring the error voltage between +/-25 mV. The beat frequency was over 100 MHz.

For the plot posted in Attachment 1, the measurement paramters are the following. Will do further measurements/analysis tomorrow.

# AG4395A Measurement - Timestamp: Jan 30 2020 - 21:58:00
# Parameter File: TFAG4395Atemplate.yml
#---------- Measurement Parameters ------------
# Start Frequency (Hz): 50000.0, 50000.0
# Stop Frequency (Hz): 1000000.0, 1000000.0
# Frequency Points: 801, 801
# Measurement Format: LOGM, PHAS
# Measuremed Input: AR, AR
#---------- Analyzer Settings ----------
# Number of Averages: 1
# Auto Bandwidth: Off, Off
# IF Bandwidth: 1000.0, 1000.0
# Input Attenuators (R,A,B): 0dB 0dB 0dB 
# Excitation amplitude = -20.0dBm

Quote:

yes, its fine to use this with a level 3 or level 7 mixer; let's see some PM transfer functions !

Quote:

Is this sufficient enough for the mixer to work?

Attachment 1: Figure_2.png
Figure_2.png
  6199   Sun Jan 15 10:28:02 2012 DenUpdateAdaptive Filteringdelays

We can account for delays in the oaf system by compensating it in the adaptive path of the filter. But using only this procedure is not enough. Parameters mu and tau should be chosen accurately:

w = (1 - tau) * w;

w += mu * dw / norm;

NLMS algorithm without considering delays works well for mode cleaner length and gur1 seismometer signals, significantly reducing MC_F  with parameters mu=1, tau=0. These parameters are considered because nlms algorithm should converge with the highest speed when mu=1. However, if the system has a delay so at time moment n:

error_signal [n] = desired_signal [n] - filter_output [n-delay];

then the adaptive filter diverges for the same parameters mu=1 and tau=0 even for delay=1. For that reason we make the same calculations with tau = 1e-4 and tau = 1e-2 without reducing mu conserving the adaptation rate and get the same result as nlms algorithm without delays. Next figure shows MC_F signal, error after applying e-nlms filter with tau=1e-4 and tau=1e-2. "e-" is added to show that  a small number (epsilon) is added to the norm of the signal in order to prevent the filter from diverging in the beginning of the process when the norm is not well-determined yet.

2048_tau.png

The test was done offline with the sampling frequency 2048 Hz, without downsampling and any filters. We can see that tau=1e-4 is still not enough, tau=1e-3 or tau=1e-2 is as good as nlms without delays, tau=1e-1 and high are also bad.

Correctly choosing tau we have some freedom for delay compensation in the adaptation path. This is important as we do not know exactly what is the delay in the real system. We can measure it approximately. In order to figure out the range of reasonable delay errors we make a test with delay = 1, but to the adaptation path we give delays from 0 to 10. It turns out that adaptation path delays greater then 5 make the filter diverge, delays in the range 0-3 produce a reasonable error. In the figure below errors with adaptation path delays = 1 (correct) and 3 are presented.

2048_delays.png

  4554   Thu Apr 21 21:24:41 2011 kiwamuUpdateLSCdemod board : new 90 deg splitter

A new 90 degree splitter, PSCQ-2-51W, has arrived today and I installed it on a demod board called AS11.

Results of the I-Q phase measurement with the new splitter will be reported soon.

 

 * Picture 1 = before removal of the handmade coil

 * Picture 2 = after removal of the coil and the associated capacitors

 * Picture 3 = after soldering PSCQ-2-51-W

DSC_2949_ss.jpg

DSC_2951.JPG

DSC_2952_ss.jpg

Quote from #4358

 First of all we will replace the home-made 90 degree splitter (see this entry) by a commercial splitter, PSCQ-2-51-W+ from Mini circuit. This is the step 1 basically.

  4555   Thu Apr 21 21:46:22 2011 kiwamuUpdateLSCdemod board : new 90 deg splitter

A less LO power dependence on the relative phase was found. The new 90 deg splitter works better.

From -3 dBm to 10 dBm in LO power, the relative phase is within 90 +/- 5 deg.

As a comparison I plot the phase that I measured when the handmade coil had been there (green curve in the plot).

relativephase.png

 

 I will also measure amplitude unbalances between I and Q.

Quote from #4554

A 90 degree splitter, PSCQ-2-51W, has arrived today and I installed it on a demod board called AS11.

Results of the I-Q phase measurement with the new splitter will be reported soon.

 

 

  4560   Fri Apr 22 11:08:50 2011 kiwamuUpdateLSCdemod board AS11 : amplitude imbalance

Amplitude imbalance between I and Q in a demod board, AS11, with the new 90 deg splitter was measured.

It shows roughly 10% amplitude imbalance when the LO power is in a range from 0 to 5 dBm. Not so bad.

 

  With the handmade coil there used to be a huge imbalance (either I or Q goes to zero volt while the other keeps about 1 V rms) as the LO power decreases.

But with the new 90 deg splitter now there are no more such a huge imbalance.

The remaining 10 % imbalance possibly comes from the fact that we are using ERA-5 in each I and Q path. They may have such gain imbalance of 10%.

We should check the ERA-5 gains so that we can confidently say ERA-5 causes the amplitude imbalance.

Then our plan replacing the ERA-5s (see here) will sound more reasonable.

IQamplitude.png

 

Quote from #4555

The new 90 deg splitter works better.

 I will also measure amplitude unbalances between I and Q.

 

  4538   Mon Apr 18 13:05:57 2011 kiwamuSummaryLSCdemod board modification

Here is the idea how we upgrade the demodulation boards.

Basically we go ahead with two steps as depicted in the cartoon diagram below.

Once we finish the first step of upgrade, the board will be ready to install although the circuit won't be awesome in terms of noise performance.

 

demod_board.png

 

* * * (details) * * *

 First of all we will replace the home-made 90 degree splitter (see this entry) by a commercial splitter, PSCQ-2-51-W+ from Mini circuit. This is the step 1 basically.

At this point the boards will be ready to use in principle. I asked Steve to get three 90 degree splitters so that we can have at least three demodulators for the dual-recycled Michelson locking.

If they work very fine we will buy some more 90 degree splitters for full locking.

While we try to lock the dual-recycled Michelson once we will get a Cougar amplifier, remove all ERA-5s and install it such that we don't have to gain up and down in the circuit. This is the last step.

  277   Sun Jan 27 13:13:21 2008 tobinMetaphysicsGeneraldeparture
It's been grand. Thanks for having me!

GWAVES IN '08!

Sugar napoleons may be forwarded to T. F., c/o LLO, P.O. Box 940, Livingston, LA 70754-0940.
  2525   Tue Jan 19 02:39:57 2010 kiwamuUpdateElectronicsdesign complete --- triple resonant circuit for EOM ---

The design of the triple resonant circuit has been fixed.

I found the optimum configuration, whose gain is still 11 at 55MHz even if there are realistic losses.

As I mentioned in the last entry, there are infinite number of the similar solutions to create the same resonant frequencies.

However owing to the effect of the losses, the resultant gain varies if the similar solution changes

The aim of this study is to select the optimum solution which has a maximum gain ( = the highest impedance at the resonance ).

In order to handle the losses in the calculation, I modeled the loss for both inductors and the capacitors.

Then I put them into the circuit, and calculated the impedance while changing the solutions.

 


 

(method)

1). put the scaling parameter as k in order to create the similar solution.

2). scale the all electrical parameters (L1, L2,...) by using k, so that C1'=C1 x k, L1'=L1/k ,...

3). Insert the losses into all the electrical components

4). Draw the impedance curve in frequency domain.

5). See how the height of the impedance at the resonance change

6). Repeat many time this procedure with another k.

7). Find and select the optimum k

scaling.png

There is a trick in the calculation.

I put a capacitor named Cpp in parallel to the EOM in order to scale the capacitance of the EOM (see the schematic).

For example if we choose k=2, this means all the capacitor has to be 2-times larger.

For the EOM, we have to put Cpp with the same capacitance as Cp (EOM). As a result these two capacitors can be dealt together as 2 x Cp.

So that Cpp should be Cpp = (k-1) Cp, and Cpp vanishes when we choose k=1.

 

The important point is that the scaling parameter k must be greater than unity, that is k > 1.

This restriction directly comes from Cp, the capacitance of the EOM, because we can not go to less than Cp.

If you want to put k < 1, it means you have to reduce the capacitance of the EOM somehow (like cutting the EO crystal ??)

 

(loss model)

I've modeled the loss for both the inductors and the capacitors in order to calculate the realistic impedance.

The model is based on the past measurements I've performed and the data sheet.

   Loss for Capacitor :  R(C) = 0.5 (C / 10pF)^{-0.3} Ohm

   Loss for Inductor :    R(L) = 0.1 ( L / 1uH) Ohm

Of course this seems to be dirty and rough treatment.

But I think it's enough to express the tendency that the loss  increase / decrease monotonically as  L / C get increased.

These losses are inserted in series to every electrical components.

( Note that: this model depends on both the company and the product model. Here I assume use of Coilcraft inductors and mica capacitors scattered around 40m )

 

( results )

The optimum configuration is found when k=1, there is no scaling. This is the same configuration listed in last entry

Therefore we don't need to insert the parallel capacitor Cpp in order to achieve the optimum gain.

The figure below shows the some examples of the calculated impedance. You can see the peak height decrease by increasing the scale factor k.

realistic.png

The black dash line represents the EOM-loss limit, which only contains the loss of the EOM.

The impedance at the resonance of 55MHz is 6.2 kOhm, which decreased by 3% from the EOM-loss limit. This corresponds to gain of G = 11.

The other two peaks, 11MHz and 29.5MHz dramatically get decreased from EOM-loss limit.

I guess this is because the structure below 50MHz is mainly composed by L1, L2, C1, C2.

In fact these components have big inductance and small capacitance, so that it makes lossy.

 

( next step )

The next step is to choose the appropriate transformer and to solder the circuit.

  2528   Tue Jan 19 03:20:28 2010 KojiUpdateElectronicsdesign complete --- triple resonant circuit for EOM ---

First I was confused, but now I think I understood.

My confusion:
If the k get bigger, L get smaller, C get bigger. This makes R(L) smaller and R(C) smaller. This sounds very nice. But why smaller k is preferable in the Kiwamu's result?

Explanation:
The resultant impedance of the network at a resonance is determined by Zres = L/(R C) or something like that. Here R = R(L)+R(C). (I hope this is right.)

Here larger Zres is preferable. So smaller R is nice.

But If the speed of reduction for R is slower than that of L/C (which is proportional to k^-2), increasing k does not help us to increase of Zres. And that's the case.

This means "if we can put the LC network in the box of EOM, we can do better job!" as we can reduce Cp.

Quote:

scaling.png


   Loss for Capacitor :  R(C) = 0.5 (C / 10pF)^{-0.3} Ohm

   Loss for Inductor :    R(L) = 0.1 ( L / 1uH) Ohm

  6817   Thu Jun 14 04:53:39 2012 yutaSummaryGreen Lockingdesigning ALS loop for mode scan

[[Requirement]]
 Arm cavity FWHM for IR is

  FWHM = FSR / F = c/(2LF) = 8 kHz.

 In cavity length, this is

  L/f * FWHM = 40m/(c/1064nm) = 1.2 nm

 So, to do mode scan nicely, arm length fluctuation during resonant peak crossing should be much less than 1.2 nm.


[[Diagram]]
 Let's consider only ADC noise and seismic noise.
ALSloop.png

* S: conversion from Y arm length to the beat frequency

  dL/L = df/f

 So,

  S = df/dL = f/L = c/532nm/40m = 1.4e7 MHz/m


* W: whitening filter

 We set it to flat gain 50. So,

  W = 50


* D: AD conversion of voltage to counts

 D = 2^16counts/20V = 3300 counts/V


* B: frequency to voltage conversion of the beatbox.

 We measured BWD(elog #6815). When we measured this, W was 10. So, the calibration factor at 0 crossing point(~ 50 MHz) is

  B = 1400*0.048/10/D = 0.0021 V/MHz


* A: actuator transferfunction

 I didn't measure this, but this should look like a simple pendulum with ~ 1 Hz resonant frequency.


* n_ADC: ADC noise

 ADC noise is about

  n_ADC = sqrt(2*LSB^2*Ts) = sqrt(2*(20V/2^14)**2*1/64KHz) = 1.6 uV/rtHz


* n_seis: seismic noise

 We measured this by measuring C1:ALS-BEATY_COARSE_I_IN1. This is actually measuring

  D(WBSn_seis + n_ADC)

 Calibrated plot is the red spectrum below.


* F: servo filter (basically C1:ALS-YARM)

 We need to design this. Stabilized arm length fluctuation is

  x_stab = 1/(1+G)*n_seis + G/(1+G)*n_ADC/(WBS)

 where openloop transferfunction G = SBWDFA.
 Below ~ 50 Hz, n_seis is bigger than n_ADC/(WBS). We don't want to introduce ADC noise to the arm. So, UGF should be around 50 Hz. So, we need phase margin around 50 Hz.
 We also need about 10^3 DC gain to get the first term comparable to the second term.

 Considering these things, openloop transferfunction should look like the below left. Expected error signal when ALS on is the below right. I put some resonant gain to get rid of the peaks which contribute to the RMS (stack at 3.2Hz, bounce at 16.5 Hz).
 Inloop RMS we get is about 0.3 nm, which is only 4 times smaller than FWHM.
ALSopenloop.pngyarmlength.png



[[Discussion]]
 We need to reduce RMS more by factor of ~ 30 to get resolusion 1% of FWHM.
 Most contributing factor to the RMS is power line noise. We might want comb filters, but it's difficult because UGF is at around this region.

 So, I think we need more fancy whitening filters. Currently, we can't increase the gain of the whitening filter because SR560 is almost over loading. Whitening filter with zero at 1 Hz might help.

  3647   Tue Oct 5 11:42:20 2010 kiwamuSummaryGreen Lockingdeveloping green locking plant

 With a help from Joe, I made a diagram of the simulated plant for green locking in order to get better understanding and consensus.

Eventually these simulated plants will help us developing (sometimes debugging) the digital control systems.

Here is the diagram which tells us how we will setup and link the control/plant models and on which machine they will be running.

green_sm3.png

 

Basically upper side represents the realtime control, and the lower side is the simulated plant.

The models are talking to each other via either a local shared memory (orange line) or the reflective memory network (purple line).

 Each model is stil not systematically named, at some point we have to have an absolute standard for naming the models.

 

- current model names -

  GCV = Green Control model at Vertex

  GCX(Y) = Green Control model at X (Y) end

  GPV = Green Plant model at Vertex

 

 - things to be done -

1. let the RFM work

2. revise the old plant models : SUP, SPX(Y) and LSP

 

  13290   Mon Sep 4 18:18:29 2017 ranaUpdateLSCdewhite switching: FOTON settings

not immediately necessary, since you have already got it sort of working, but one of these days we should optimize this for real. In the past, we used to do this by putting a o'scope on the coil Vmon during the switching to catch the transient w/ triggering. We download the data/picture via ethernet. Run for loop on tolerance to see what's what.

  1. Went into the Foton filter banks for all the coil output filters, and modified the "Output" settings to be on "Input crossing", with a "Tolerance" of 10 and a "Timeout" of 3 seconds. These settings are to facilitate smooth transition between the two signal paths (without and with coil-dewhitening). The parameters chosen were arbitrary and not optimized in any systematic manner.

 

  5765   Sun Oct 30 23:01:51 2011 ZachUpdateSUSdiagAllSUS -- automated input matrix generator

I finally got around to wrapping up the SUS input matrix diagonalizer. The files I have added to ...scripts/SUS/peakFit are:

  • kickAll: Restores all SUS angle biases using /cvs/cds/rtcds/caltech/c1/medm/c1ifo/cmd/C1IFO_OPTICrestore.cmd XXXX &, then runs 'freeswing all'. Finally, writes an elog entry with the time when the optics were kicked and saves the gps time to 'kickAll.time'.
  • diagAllSUS.m: An M-file that calls all the other individual M-files needed for the matrix generation. What it does:
    • Reads kick time from kickAll.time
    • Runs getSensors.m to get time series from all optics' sensors
    • Runs makeSUSSpectra.m to generate spectra from time series
    • Runs findPeaks.m to fit spectra for peak frequencies
    • Loops through all optics and runs, in sequence:
      • inmat = findMatrix(XXXX) to generate the matrix for each optic
      • writeSUSinmat(XXXX,inmat) to write that matrix to the frontend
  • diagAllSUS: A wrapper for diagAllSUS.m. It also writes an elog entry and attaches the pre and post spectra demonstrating the diagonalization. The entry following this one is an example.

The following lines should eventually be added to the controls@nodus crontab:

0 8 * * 0 /cvs/cds/rtcds/caltech/c1/scripts/SUS/peakFit/kickAll

0 18 * * 0 /cvs/cds/rtcds/caltech/c1/scripts/SUS/peakFit/diagAllSUS

(i.e., do the kick at 8am on Sundays and run the diagonalization 10 hrs later at 6pm). They can be done on a different machine but then my elog commands will need to be modified.

Before we add them, we should check that they do, in fact, work. We can do this sometime while I'm at the 40m this week.
 

  3844   Tue Nov 2 11:34:53 2010 josephb, alexUpdateCDSdiagconfd running, excitations back in dtt

Problem:

Diagnostic test tools was starting with errors.

Cause:

After the reboot of the frame builder machine yesterday by Alex, the diagconfd daemon was not getting started by xinetd.  There was a sequence error in the startup where xinetd was being called before mounting drives from linux1.

Important Note:

If you do not see the "nds" line you would not have diagnostic tests enabled in the DTT:

[controls@rosalba apps]$ diag -i | grep nds
nds * * 192.168.113.202 8088 * 192.168.113.202

Solution:

Alex changed /etc/xinetd.d/diagconfd file to point to /opt/apps/gds/bin/diagconfd instead of /opt/apps/bin/diagconf.  He also ensured xinetd started after mounting from linux1.

Alex's Suggestion:
My feeling is we should get rid of this feature and have an NDS address
entry box in the "Online" tab in the DTT with the default "nds". I
mentioned this to Jim Batch and he greed with me, so maybe he is going to
implement this. So maybe you guys want to request the same thing too, send
the request to Rolf and Jim, so we can have the last demon exercised.

  2146   Mon Oct 26 19:12:50 2009 kiwamuUpdateLSCdiagnostic script for LSC timing

The diagnostic script I've written is available in the 'caltech/users/kiwamu/work/20091026_OMC-LSC-diag/src'.

To run the script, you can just execute 'run_OMC_LSC.sh' or just call the m-file ' OMC_LSC_timinig.m'  from matlab.

 

NOTES:

The script destructs the lock of DARM and OMC, be careful if you are working with IFO.

  4026   Wed Dec 8 12:47:18 2010 kiwamuUpdateSUSdiagonalisation of ITMX input matrix

The input matrix of ITMX has been diagonalized.

The evaluation of this diagonalisation  will be done tonight by freely swinging ITMX again.

(Somehow I couldn't get any data for ETMX from the DAQ channels. I will try it again tonight.)

 


(details)

For solving the matrix, I used Yuta's python code called inmartixoptimizer.py.

I took the transfer functions of UL->UR, UL->LL and UL->LR as described in this entry.

In the measurement, the frequency bin was set to 0.001 Hz and the data were 50 times averaged on dtt.

 

Here is the new input matrix.

[[ 0.87059649  1.14491977  1.07992057  0.90456317]
 [ 0.64313916  0.55555661 -1.44997325 -1.35133098]
 [ 1.13979571 -1.19186285 -0.89606597  0.77227546]]

This matrix should give a better performance than before.

  7511   Tue Oct 9 17:16:14 2012 DenUpdateSUSdiagonalization

I went inside to align the beam on WFS and noticed that oscillations in yaw are ~10 times stronger then in pitch. I've plot rms of pitch and yaw measured by LID sensors and saw that MC3 yaw rms motion is a few times larger then pitch.

Also MC1 input diag matrix does not diagonalize signals for pitch and yaw. In the spectrums of these signals all 4 resonance are equally seen during the free swinging. I think we should rediagonalize MC1.

Another thing is that if MC1 and MC3 are on the same stack,  pitch and yaw spectrums of these mirrors should be comparable. But MC1 signal is ~2-3 times larger then of MC3. I think we should correct calibration.

Attachment 1: mc123_rms.pdf
mc123_rms.pdf
Attachment 2: mc1_diag.pdf
mc1_diag.pdf
Attachment 3: mc123_rms.pdf
mc123_rms.pdf
  7512   Tue Oct 9 17:33:37 2012 jamieUpdateSUSdiagonalization

Quote:

I went inside to align the beam on WFS and noticed that oscillations in yaw are ~10 times stronger then in pitch. I've plot rms of pitch and yaw measured by LID sensors and saw that MC3 yaw rms motion is a few times larger then pitch.

What are "LID" sensors?  Do you mean the OSEM shadow sensors?  I'm pretty sure that's what you meant, but I'm curious what "LID" means.

 

  7525   Thu Oct 11 00:28:30 2012 DenUpdateSUSdiagonalization

I've written MC123 input matrixes to the front-end.

MC1 diagonalization is poor, better then before, but still pitch is seen in pos and yaw. Either smth is malfunctioning or flags touch sensors and do not move freely. On the plot mc1_new black lines - before, red - after rediagonalization.

Attachment 1: mc1_new.pdf
mc1_new.pdf
Attachment 2: mc123_new.pdf
mc123_new.pdf
  7526   Thu Oct 11 01:30:11 2012 DenUpdateSUSdiagonalization

Quote:

MC1 diagonalization is poor, better then before, but still pitch is seen in pos and yaw. Either smth is malfunctioning or flags touch sensors and do not move freely. On the plot mc1_new black lines - before, red - after rediagonalization.

 I've actuated on MC1 with UL, UR, LR, LL coils in turn and measured sensor readings. All coils separately work fine from the first look.

On the plot: black - free mirror, blue - UL coil actuation, green - UR, grey - LR, red - LL.

Attachment 1: mc1_coils.pdf
mc1_coils.pdf
  7532   Thu Oct 11 14:40:20 2012 DenUpdateSUSdiagonalization

Quote:

MC1 diagonalization is poor, better then before, but still pitch is seen in pos and yaw. Either smth is malfunctioning or flags touch sensors and do not move freely. On the plot mc1_new black lines - before, red - after rediagonalization.

 I've manually corrected MC1 input matrix by looking at UL, UR, LL, LR transfer functions between each other. This improved pos significantly and slightly yaw.

Attachment 1: mc1.pdf
mc1.pdf
  3912   Sat Nov 13 15:53:05 2010 yutaUpdateCDSdiagonalization of MC input matrix

Motivation:
  MC is aligned from the A2L measurement, but to do the beam centering more precisely, we need coils to be balanced.
  There are several ways to balance the coils, like using oplev or WFS QPD RF channels.
  But oplev takes time to setup, especially for MC3. Also, c1ioo WFS channels were newly setup and haven't been checked yet.
  So, I decided to use OSEM sensors.
  An OSEM sensor itself is sensitive to every DOF of an optic motion, but we can diagonalize them using 4 OSEM sensors and proper input matrix.

Method:

  1. Measure transfer functions between
     ULSEN and URSEN (H_UR(f))
     ULSEN and LRSEN (H_LR(f))
     ULSEN and LLSEN (H_LL(f))

  2. Make a matrix A.

    A =  [[ 1           1           1          ]
          [ H_UR(f_pos) H_UR(f_pit) H_UR(f_yaw)]
          [ H_LR(f_pos) H_LR(f_pit) H_LR(f_yaw)]
          [ H_LL(f_pos) H_LL(f_pit) H_LL(f_yaw)]]


    where f_dof are resonant frequencies.

  3. A is

    s = Ad


   where vectors s^T=[ULSEN URSEN LRSEN LLSEN] and d^T=[POS PIT YAW].
   So,

    d = Bs = (A^TA)^(-1)A^Ts

   where A^T is transpose of A.

   B is the input matrix that diagonalizes 3 DOFs.

What I did:

  1. Measured the TFs using diaggui and exported as ASCII.

  2. Made a script that reads that TF file, calculates and sets a new input matrix B.
    /cvs/cds/caltech/users/yuta/scripts/inputmatrixoptimizer.py
   You need to set resonant frequencies to use the script.

   New input matrices for MCs are;

C1:SUS-MC1_INMATRIX
[[ 1.17649712  0.94315611  0.85065054  1.02969624]
 [ 0.55939288  1.28066594 -0.85235358 -1.3075876 ]
 [ 1.23467139 -0.74521928 -1.29394051  0.72616882]]

C1:SUS-MC2_INMATRIX
[[ 1.12630748  1.01451545  0.9013457   0.95783137]
 [ 1.03043025  0.67826036 -1.37270598 -0.91860341]
 [ 0.83546271 -1.26311029 -0.6456881   1.2557389 ]]

C1:SUS-MC3_INMATRIX
[[ 1.18212117  1.26419447  0.77744155  0.77624281]
 [ 0.79344415  0.84959646 -1.10946339 -1.247496  ]
 [ 1.00225331 -0.84807863 -1.21772132  0.93194674]]


  I ignored SIDE this time.

Result:

  Spectra of each SUSDOF_IN1_DAQ before diagonalization (INMATRIX elements all 1 or -1) were
MCspectraNov09.png

  After diagonalization, spectra are
MCspectraNov13.png

  As you can see, each SUSDOF has only single peak (and SIDE peak) after the diagonalization.
  SUSSIDE still has 4 peaks because SIDE is not included this time.

  For MC2, POS to SUSPIT and POS to SUSYAW got worse. I have to look into them.

Effect of resonant frequency drift:

  As you can compare and see from the spectra above, resonant frequencies of MC1 are somehow drifted(~0.5%) from Nov 9 to Nov 13.
  If resonant frequency you expected was wrong, calculated input matrix will be also wrong.
  The effect of 0.5% drift and wrong input matrix can be seen from this spectra. DOFs are not clearly separated.
 MC1spetra_wrongmatrix.png

Plan:

 - learn how to use diaggui from command line and fully automate this process
 - balance the coils using these diagonalized SUSPOS, SUSPIT, SUSYAW

  4718   Sun May 15 03:58:19 2011 ranaUpdateCDSdiagonalization of MC input matrix

There has been some input matrix diagonalization in the past by Yuta and Kiwamu, but I find the automation to be not totally satisfactory.

It would be better if we could automatically fit the data to find the Suspended optic eigenfrequencies and then use that to get the matrix. So I wrote a peak fitter to get the matrix.

It gets the data from mafalda with NDS2, then it makes the PSDs, and then starts with some initial guesses (based on looking at the plots) and them uses fminsearch to get the peak frequencies and Q's.

Using the output of this, we can use Yuta's method and take the passive transfer functions with the free swing data (from April 30, so we got do do it quick) to get the input matrix.

 

Doing the SUS input matrix is nice for having good damping (as long as we remember to include SIDE), but my motivation is to produce a good null stream from the 4 face sensors so that we can estimate the sensor noises at all times.

Attachment 1: mc1.png
mc1.png
  4746   Thu May 19 00:23:44 2011 ranaUpdateCDSdiagonalization of MC input matrix

 I've moved all of my SOS peak fitting stuff into the scripts area so that Leo can make it better:

/cvs/cds/rtcds/caltech/c1/scripts/SUS/peakFit

findPeaks.m gets the data and makes the fitted spectra that I put in the previous entry.

findMatrix.m is the barely started script that ought to take the TF data and output the matrix to the MEDM screen.

  4886   Sun Jun 26 16:17:22 2011 ranaUpdateCDSdiagonalization of MC input matrix

I have updated the scripts/SUS/peakFit/ directory so that it now finds the SUS input matrix coefficients in addition to just finding the free-swinging peaks.

Procedure:

  1. Get OSEM sensors data via NDS2 from a time when the optics have been kicked and then left free swinging.
  2. Downsample the data to 64 Hz and save.
  3. Make power spectra with a 1 mHz resolution (i.e. we need a few hours of data) and  ~10 averages.
  4. use the fminsearch lorentzian peak fitter -> save the peak frequencies
  5. Make Transfer Function estimate matrix at the peak frequencies between all OSEMs (this makes a 5x4 complex matrix)
  6. The matrix should be real, so make sure its mostly real and then take the real part only
  7. Normalize (height of biggest peak for each f_DOF should be 1)
  8. Add a Butterfly mode vector. This makes the sensing matrix go from 5x4 to 5x5. (Butterfly a.k.a. Pringle)
  9. Invert
  10. Normalize so that the biggest element in each Sensor2DOF column is 1.
  11. Load values into MEDM screen and then verify by another free swinging data run.

 

The attached PDF shows how much rejection of the unwanted DOFs we get between the existing diagonal input matrix and this new empirical matrix. Previously, the decoupling was only a factor of a few for some of the modes. Now the decoupling is more like orders of magnitude (at least according to this calculation). It will be worse when we load it and then try another free swinging run. However, the fact that the suppression can be this good means that the variation in the coefficients at the ~hours time scale is at least this small (~< 0.1%)

 

That's the basic procedure, but there are a lot of important but mainly technical details:

  1. Free swinging data must be taken with the angle bias ON. Otherwise, we are not measuring the correct sensing gain (i.e. the magnets are not in their nominal place within the OSEM-LED beam)
  2. Data must be checked so that the shadow sensor outputs are in their linear regime: if they are exploring the cubic part, then the fundamental is being suppressed.
  3. Instead of just using the peak frequency, I average a few points around the peak to get better SNR before inversion. I think this will make the results more stable.
  4. All previous input matrix diagonalization efforts (Buckley, Sakata & Kawamura, Black, Barton, Gonzalez, Adhikari & Lawrence, Saulson,...) for the past ~15 years have been using the spectra's peak height data. Today's technique uses the TF and so is more precise. The coherent transfer function is always better than just using the magnitude data.
  5. This method is now fairly automatic - there's no human intervention in fudging values, choosing peak heights, frequencies, etc.
  6. We'll have to rerun this, of course, after the mirrors are aligned and after the OSEM whitening fiasco is cleaned up somewhat.

I'll set the optics to be aligned and then swing tonight.

Attachment 1: inMatDiag.pdf
inMatDiag.pdf
  5136   Mon Aug 8 00:12:58 2011 ranaUpdateCDSdiagonalization of MC input matrix

I've finally completed the SUS/peakFit/ scripts which find the new input matrix for the SUS. MC1, MC2, MC3, and ITMX have been matrix'd.

I tried to do the BS, but it came out with very funny matrix elements. Also the BS is missing its DAQ channels again (JAMIE !) so we can't diagnose it with the free swinging method.

To continue, we have to get some good data and try this again. Right now there are some weird issues with a lot of the optics. I've also set the damping gains for the optics with the new matrices.

 Ex.

new_matrix = findMatrix('ITMX')

writeSUSinmat('ITMX', new_matrix)

writeSUSinmat.m

this script writes the values to the MEDM input SUS matrix. To do the writing, I used the low level 'caput' command instead of ezcawrite since the ezca libraries are getting deprecated.

caput doesn't really have good diagnostics, so I use matlab to check the return status and then display to the terminal. You can just rerun it if it gives you an error.

 

 

A coupled of normalization notes:

1) The POS/PIT/YAW rows are scaled so that the mean of abs(FACE elements) = 1. Previously, I had the max element = 1.

2) The SIDE row is scaled so that the SIDE element = +1.

3) I then normalized the ROWS according to the geometrical factors that Jamie has calculated and almost put into the elog.

 

All these scripts have been added to the SVN. I've removed the large binary data files from the directory though. You can just rsync them in to your laptop if you want to run this stuff remotely.

  5137   Mon Aug 8 00:58:26 2011 ranaUpdateCDSdiagonalization of MC input matrix

Besides the purpose of correctly tuning the suspensions, my hidden goal in the input matrix diagonalization has been to figure out what the 'true' sensing noise of the OSEMs is so that we can accurately predict the noise impact on the OAF.

The attached plot shows the DOFs of ITMX calibrated into microns or microrad as per Jamie's ethereal input matrix calculations.

The main result is in the ratio of POS to BUTTER. It tells us that even at nighttime (when this data was taken) we should be able to get some reduction in the arms at 1 Hz.

Whether we can get anything down to 0.1 Hz depends on how the arm control signal compares to the POS signal here. I leave it to Jenne to overlay those traces using a recent Arm lock.

Attachment 1: null.png
null.png
  6413   Wed Mar 14 10:06:26 2012 steveUpdateGreen Lockingdichroic mirror quotes

Dichroic mirror quotes are in the wiki.

ATF is pricy.

We got a good price from Laseroptik, but the wedges are 5 arcminutes. The fused silica grade is 0F, meaning the  homogeneity is 5 ppm instead of 1ppm.  I requested an other large wedge quote on the substrates.We may have to get substrates from somebody else and ship it to Germany

MLT quote is outrageously high

REO is not interested in this low volume job.

 

  6435   Thu Mar 22 08:14:21 2012 steveUpdateGreen Lockingdichroic mirror quotes with large wedge

Quote:

Dichroic mirror quotes are in the wiki.

ATF is pricy.

We got a good price from Laseroptik, but the wedges are 5 arcminutes. The fused silica grade is 0F, meaning the  homogeneity is 5 ppm instead of 1ppm.  I requested an other large wedge quote on the substrates.We may have to get substrates from somebody else and ship it to Germany

MLT quote is outrageously high

REO is not interested in this low volume job.

 

 The Laseroptik quote is here.The 2 degrees wedge cost is $40 on each optics!  See wiki

  2296   Thu Nov 19 08:53:12 2009 peteFrogsEnvironmentdiesel fumes

 Instead of doing RCG stuff, I went to Millikan to work on data analysis as I couldn't stand the fumes from the construction.  (this morning, 8am) 

ELOG V3.1.3-