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ID Date Author Type Category Subjectup
  7076   Thu Aug 2 03:06:57 2012 SashaUpdateSimulationsLS Plant (LSP) is officially ONLINE

My ls plant compiled!! The RCG code can now be found in /opt/rtcds/rtscore/tags/advLigoRTS-2.5. I uploaded a copy of c1lsp.mdl onto the svn.

The weird "failed to connect" error was due to the fact that I named my inputs the same thing as my goto/from tags, so the RCG got confused. Once I renamed my inputs, it worked! I'm not sure what happened to the original "not enough parts" error; it didn't appear a single time during the rebuilding process. Anyway, I made the PDH block much neater, though the lines between PDH and ADC are looking wonky (this is purely an aesthetic problem, not a "oh god my simulation will DIE right now if I don't fix it" problem). I'll fix it in the morning; screenshot attached!

The original c1lsp was kind of sad. I updated it extensively and brought it into the modern era with color. The original c1lsp.mdl should also be on the svn. Tommorow, I'll get started on figuring out how to get LIGO specific noises from white noise.

Attachment 1: Screenshot-1.png
Screenshot-1.png
  4689   Wed May 11 13:54:32 2011 steveUpdateLSCLSC power supplies

Aux- rack _1Y2 is just behind 1Y3  It contains Kepco Analoge DC power supplies for +- 5, 15 and 24V

Placing these power supplies away from the LSC rack was an effort to minimize pick up from them.

 

Attachment 1: P1070679.JPG
P1070679.JPG
  4523   Thu Apr 14 01:03:43 2011 KojiUpdateLSCLSC Campaign ~ Status

Target: To lock the Michelson with the new RF/LSC


Status

RF generation box: READY - already ready to go to the IOO rack. (Suresh)

RF distribution box: In Progress - the internal components are to be connected. (13th evening - Suresh)

Placing PD and CCD: Done - PD and CCD on the AP table (13th Afternoon - Aidan, Larisa with supervision of Kiwamu)

Cabling1: Done - PD signal AP table to the demodulator (13th Afternoon - Jamie with supervision of Suresh)

Cabling2: Done - RF generation box (IOO Rack) to the demodulator

Demodulator: In Progress - Test and install (13th night - Kiwamu with supervision of Suresh)

LSC model: Done - Run the new LSC model. (It is named as "C1LST" so far) (13th evening - Jamie)

LSC medm: Done on 14th - Modify the current LSC medm screens Update the EPICS database Adjust the matrices (- Jenne with supervision of Koji)

  5210   Fri Aug 12 16:42:51 2011 YoichiConfigurationLSCLSC Feed Forward Compensator
I've been working on adding feed forward (FF) paths to our LSC code.
So far, I've made a basic feed forward functionality connected
to the feedback path of the LSC model.

As is shown in the MEDM screen, this feed forward compensator (FFC)
takes feedback signals from several DOFs (MICH, PRCL, SRCL, CARM, XARM and YARM)
and put those signals through some filters. Then the filtered signals are
summed into the feedback signals.

There are input and output matrices to select which signal goes to which signal.

Usually, we just want to feed forward MICH to DARM. We may also want to do PRCL
to DARM and SRCL to DARM if necessary.
It is more unlikely that we use CARM for FF. But I put it there just in case.
XARM and YARM will not going to be used as is. These are place holders for future
experiments, like low frequency FF from seismic channels or something like that.
Feed forward is almost always done to DARM. But just in case we want to do some
fancier FF, like FF from PRCL to MICH, the output matrix is there to chose where
the signals will go.

I haven't really tested it because we don't have the interferometer working.
But I checked the signal flow, and it seems the model is working correctly.

=== Implementation ===
FFC is running in a separate realtime code, called c1ffc.
This is to offload c1lsc from the possible intense calculations, like adaptive stuff,
performed in the FFC in the future.
The LSC signal is passed to c1ffc via shared memory. The calculated FF signals
are passed back to c1lsc via shared memory too.
Even though FFC is in a separate realtime model, it is still conceptually a part of LSC.
So, I used top_names tag to change the names of the channels to C1:LSC-FFC_* instead of
C1:FFC-*.

In MEDM, there is an "ENABLE" button in the FF screen. Even though it is shown in the FFC
overview screen, the button itself is in the c1lsc code, so that we can disable the FFC
even when c1ffc is dead or going crazy.

=== Background ideas ===
For those of you wondering what is this feed forward thing for, I will put a brief explanation here.
Taking MICH as an example, we get the error signal for MICH from probably REFL_55Q (or AS_55Q ?).
At low frequencies, this signal properly reflects the motion of the mirrors (mostly seismic).
However, it has much worse shot noise than DARM. At higher frequencies, like above a few tens of Hz,
the error signal is dominated by the shot noise. Feeding back this signal to, say BS, means
we are shaking the BS by the shot noise, which was otherwise quiet at high frequencies.

Now, if the BS is shaken, it has some intrinsic coupling to the DARM signal.
The mechanism is that the BS motion creates some audio frequency sidebands
and this SBs reach the AS port and beat against the local oscillator to create
fake GW signals. This is called "Loop Noise Coupling".

A well known way to mitigate this problem is feed forward.
Since we know how much we are shaking the BS (because we are doing it), and
we can measure the amount of BS to DARM coupling, we can subtract out the
loop noise by feeding forward the MICH feedback signal to the DARM actuators.
In other words, the noise SBs created at the BS is canceled on the PD by the
extra SBs created at the ETMs by the feed forward.

This is what FFC is trying to do.
Attachment 1: FFCinLSC.png
FFCinLSC.png
Attachment 2: FFC.png
FFC.png
  11445   Fri Jul 24 20:32:15 2015 ericqUpdateElectronicsLSC LO distribution box power button replaced

As happened with the RF distribution box in the IOO rack a while back, the shiny blue power button in the LSC LO distribution box failed today. I replaced it with a simple switch, but since the original was a double throw, the replacement was way too big to fit without major panel surgery. So, instead, I installed it in the grille on the roof of the chassis. It a tight press/snap fit, though; I don't think it is at risk of easily coming loose. 

After reinstalling the box, I confirmed that POX POY and AS55 could all lock arms, so I deem the operation a success.

Before:

After:

Attachment 1: 2015-07-24_15.43.56.jpg
2015-07-24_15.43.56.jpg
Attachment 2: 2015-07-24_16.57.19.jpg
2015-07-24_16.57.19.jpg
  5473   Tue Sep 20 02:21:10 2011 KojiUpdateLSCLSC MEDM screen cleaning up

I have made some cleaning up of the LSC-related MEDM screens.

- LSC overview screen: ADC OVFL and WFAA indicators are now correctly matched to it associated PD signals.

- Whitening screens now have the correct indication of the associated PD signals.

- LSC Ctrl screen, which is invoked from the overview screen by clicking the servo filters, now has the switches of the servo filters.

- LSC tab of the sitemap was cleaned up by removing the broken links.

  10390   Thu Aug 14 18:31:45 2014 ericqUpdateLSCLSC Modeling Update

 Based on the game plan, I have created a slew of updated pretty plots about our signals and loops. 

First: With measured arm losses, when do we start to see REFL DC dip? At what arm buildup powers? 

I updated my MIST model with the arm losses I've measured (Y:130ppm, X:530ppm), and some measured transmissions from the wiki, vs. the design parameters, as I used to have. Here is the DC sweep plot which is now hanging up in the control room. 

dcSweep.pdf

In this plot, I also calculated what MIST thinks the full arm power buildup will be as compared to our single arm locking, and I get something of order 200, rather than the 600 we've tossed around in discussions. Nothing else is very different in this plot from the old version; though the REFLDC dip is a little bit wider. 

Now, here are some radiation-pressure inclusive sensing transfer functions, for the anti-spring case (which in Rob's day was easier to lock for unknown reasons):

carm2TRX.pdfcarm2REFLDC.pdf

carm2REFL11.pdfdarm2AS55Q.pdf


Next: Include new AO path TFs into CM model Look at possibilities for engaging AO path 

With these TFs, and the recently measured+fit new AO TF, here are the open loop gains of the slow, digital, SqrtInv-sensed MCL CARM and fast, analog, REFLDC-sensed AO CARM loops for the region of offsets we've achieved and a little lower. The slow digital loop includes the 1k LP that we have used in the past, in addition to the normal CARM filters. I still need to figure out the right sequence of ( offset reduction / crossover frequency motion / overall gain adjustment ) that gets the coupled cavity resonance solidly within the loop bandwidth. 
 
MCLcarmLoop.pdfAOcarmLoop.pdf

 

  4982   Mon Jul 18 14:39:53 2011 JenneUpdateComputersLSC PD chans acquired

There's too much tromping around, so I'm not going to actually measure PRC length right now, but I did set some channels to be acquired (POPDC, POXDC, POYDC) in addition to ASDC which was already acquired, so that I can look at the resonance fringes when I sweep the ABSL laser (hopefully later tonight....)

  4951   Thu Jul 7 02:23:59 2011 JenneSummaryLSCLSC Whitening Filters have been fit

I have fit all of the LSC whitening filters using vectfit4.m

All the data is in my folder ..../users/jenne/LSC_WhiteningTest_29June2011/

The zpk info is saved with each plot of the fit.  The pdfs are kind of huge to stitch together (or rather my computer doesn't want to do it), so I'll just post a representative one for now.

AS55Q.png

During the daytime either tomorrow or Friday I'll adjust the actual dewhitening filters to match the measured zpk values.

  4955   Thu Jul 7 15:34:44 2011 JenneSummaryLSCLSC Whitening Filters have been fit

Quote:

During the daytime either tomorrow or Friday I'll adjust the actual dewhitening filters to match the measured zpk values.

 I made a handy-dandy table showing the zpk values for each whitening filter in the wiki: New whitening filter page

Next on the whitening filter to-do list: actually put these values into the dewhitening filters in foton.

  11607   Wed Sep 16 23:07:06 2015 ranaUpdateElectronicsLSC Whitening board: LP filters added, pictures taken

I added the 0.1 uF and 47 nF caps that I mentioned so that we can now bypass the AA filters for these channels. (mistakenly installed 47 instead of 0.47 nF on the first round and we got 350 Hz poles instead of 35 kHz)

Gautam and I checked out the AA sit and it seems that the XYCOM-220 cable which ought to allow switching of the AA filter is not connected on the XYCOM side, so the LSC AA filters are always ON. In order to bypass them, we'll need to just short the bypass control pins or just set the +5V on the board to GND, by lifting the EMI3 filter and shorting C6.

I have so far only made the changes on s/n 115 (used for AS55, REFL55, and REFL165), other 2 boards to follow soon.

Before making the AA change, we want to measure the HF spectrum the ADC for each of our main signals in the PRFPMI state. In lieu of that, we'll measure the spectrum at the I/Q mon ports of the demod boards via SR785 and then use matlab to propagate the signals to the ADC to make our estimate of how much anti-aliasing we need.

Changes relative to D990694-B:

  1. R215, R216, R217, R218, R219: 4.75k -> 9.53k.  This change was made long to make the DC gain of channels 4-8 be unity, the same as channels 1-3.
  2. 0.1 uF NPO cap in parallel with R127, R128, R129, R130, R131, R132, R133, R134.
  3. R127, R128, R129, R130, R131, R132, R133, R134 all 100k (was already like this) to keep LT1128 from floating up when input cables are disconnected.
  4. C158, C159, C160, C161, C162, C163, C164, C165, C166, C167, C168, C169, C170, C171, C172, C173, all were empty, now are 0.47 nF NPO.

I also looked at the noise in a few different configurations to see what we ought to do next.

BLACK: AS55I_IN1 with 0 dB whitening gain and whitening filter OFF, so its all just ADC noise

RED: same but with +45 dB whitening gain and WF ON, so above 10 Hz this is now the noise of the PD / demod chain

BLUE: RED w/ the anti-WF applied

PURPLE: in-loop POX11_I spectrum with x-arm locked

The conversion from counts to volts 0.0006, so the black trace is ~5 uV/rHz as expected. Its clear that we would be sort of OK for most of our channels if we just had 1 stage of whitening. I think we ought to convert the input stage into a 100:20 stage and also change the other whitenings into a 100:20 instead of 150:15. Then we'll have less gain at 15 Hz, but more at 100 Hz.

We really need to buy some surface mount capacitors, Steve - we ought to have at least 100 of all the ones in that little gray cabinet.

Attachment 1: 20150916_221210.jpg
20150916_221210.jpg
Attachment 2: out.pdf
out.pdf
  9509   Sat Dec 21 01:54:04 2013 KojiConfigurationLSCLSC Whitening for the DCPDs/CM servo replaced

The previous LSC whitening filters for the DCPDs were in an unknown state (although the transfer functions were actually measured and fit a while ago)
They had no DC gain control and some of the channels had modifications.

To make the setup clear, the filter module was replaced with the spare module without any modification.

The channels are now respoding to the whitening gain switches. So far there is no screen for the new  whitening gains yet.

Also I found that POX11 DC cable has not been connected. Now it is connected.

  9136   Tue Sep 17 18:44:29 2013 MasayukiUpdateLSCLSC calibration screen

I update the LSC calibration screen. This screen is for real time calibration of each DOF with using error signal and control signal. The formula of the calibration is

x_dis = V_err/H + A V_fb

,where x_dis is the disturbance without surpression, V_err and V_fb are error signal and control signal, H is the transfer function from the displacement to output and A is the efficiency of the actuator.

I will put the filter of 1/H into the CINV filter bank and actuator efficiency into the A filter bank.

 

Attachment 1: calibration_screen.png
calibration_screen.png
  9149   Fri Sep 20 22:49:10 2013 MasayukiUpdateLSCLSC calibration screen

Quote:

I update the LSC calibration screen. This screen is for real time calibration of each DOF with using error signal and control signal. The formula of the calibration is

x_dis = V_err/H + A V_fb

,where x_dis is the disturbance without surpression, V_err and V_fb are error signal and control signal, H is the transfer function from the displacement to output and A is the efficiency of the actuator.

I will put the filter of 1/H into the CINV filter bank and actuator efficiency into the A filter bank.

 

 I fixed the filter of the MICH real-time calibration. You can find C1CAL screen from the LSC menu 'calibration' of sitemap.

*Filter explanation

    C1CAL_MICH_CINV : the servo to convert  the error signal to displacement.

Sen_MICH :

the inverse of the transfer function from the distance to the error signal, which has the unit of count/m. In the formula this filter is represented by 1/H.

I assume this H is independent of frequency and time, and I calculated by the amplitude of the fringe of error signal. But it may change every day by drift of laser intensity and so on.  So we should follow the actual H somehow.  The temporary value of H is 3.76*10^7 count/m .

    C1CAL_MICH_A : the servo to convert the feedback signal to displacement. In formula This transfer function is represented by A

 SUS_BS;

the transfer function of the suspension of the BS. This is modeled from the measurement in elog#9127. The resonant frequency is 1.029 Hz and Q is 12.25.

 Res_A :

the response of the actuator on BS_SUS, which has the unit of m/count. The value is 1.99*10^-8 m/count. This value is measured in the measurement in elog#9121.

     C1CAL_MICH_W : the servo to handle the calibrated signal.

  m->um ;

the filter to convert the unit of signal from m to um. When this filter is on, the output is written in unit of um.

*Measurement

 I measured the power spectrum of the calibrated free running noise. The measured port was C!CAL_MICH_W_OUT. The result is in attachment 1. Also in this figure there are the plots of the Verr/H and Vfb*A.

 In low frequency region, where control loop suppresses the disturbance, you can see that the displacement is equal to the displacement of actuation (I'm not sure what happens at the point of 0.03Hz), and in high frequency region, where control loop doesn't work, the displacement is equal to the value of the Verr divided by MICH sensitivity. Also this result is similar to the my calibration result.elog#9131

Attachment 1: plot.pdf
plot.pdf
  9158   Wed Sep 25 08:11:01 2013 MasayukiSummaryLSCLSC calibration screen

 

  The real time calibration system is not correct in high frequency.

The attachment are the plot of two free running noise. Blue curve is the plot of noise calibrated with OLTF. Green one is the just fft analysed signal of the real time calibration system output. You can see the ripple in high frequency region in green curve. That is because the anti-aliasing filter and digital anti-aliasing filter. I assume the sensitivity of MI as constant but Rana mentioned that we should take these filters into account.

modeled OLTF and sensitivity H
 I put the AA filter and DAA filter effects into matlab calibration script. The attachment 2 is the modeled sensitivity of the MICH. You can find each filter properties in  elog#8555 (analog AA filter) and in elog#3961. I estimate the H gain by measuring the fringe. The attachment 3 is the plot of fringe and I averaged with green points. The actual number is 3.48e7 count/m

attachment 2: the sensitivitiy of MICH

Screenshot.png

 attachment 3: fringe of the MICH

fringe.pdf

I modeled OLTF with this H and the fitted into the measurement data. That is in attachment 4. In this OLTF I also included the DAI filter and AI filter, and ' sample and hold circuit' of DAC TF . These are  mentioned in two references. Additionally I added the time delay 309.6 us.  Yuta mentioned that in C1SUS has 125us time delay. In MICH control we have also C1LSC , so I think this time delay is reasonable. I compensated the error signal with these OLTF and MICH sensitivity.

attachment 4: OLTF of the MICH control

Screenshot-1.png

You can see that the ripple is gone in blue curve and after 5 kHz the curve is flat.

Next step

I'm trying to put the inverted AA filter and DAA filter in C1CAL_INCV servo. But the ploblem is the difference of sampling frequency, so I couldn't fix yet. One possibility is putting approximated filter. I hope I will find some good way to design these filters.

 

 

Other thing

I esitimated the FPMI noise propagated from the residual noise of IR PDH control of both ARMS. I will summarize and write these staff in this afternoon.

Attachment 1: plot.pdf
plot.pdf
  9169   Fri Sep 27 13:55:11 2013 MasayukiUpdateLSCLSC calibration screen

  I added the DAQ channel to all output of calibration servo. The name of channels are C1CAL_(plant name)_W_OUT_DQ.

I recompiled and restarted the model. Also I committed the changes to the svn of the calibration model.

  9172   Fri Sep 27 21:01:50 2013 MasayukiUpdateLSCLSC calibration screen

 

 I fixed the XARM and YARM real time calibration servo.

I also change the C1CAL_MICH_A servo. Now the actuator response and the suspension TF are combined together and that filter name is BS_act. C1CAL_XARM_A and C1CAL_YARM_A have same kind of filters, ETMX_act and ETMY_act.

There are AI filter in each A servo and inv_AA, inv_DAA filters in CINV servo, but it's doesn't work correctly yet.

  9174   Mon Sep 30 11:33:15 2013 ranaUpdateLSCLSC calibration screen

Quote:

  I fixed the XARM and YARM real time calibration servo.

I also change the C1CAL_MICH_A servo. Now the actuator response and the suspension TF are combined together and that filter name is BS_act. C1CAL_XARM_A and C1CAL_YARM_A have same kind of filters, ETMX_act and ETMY_act.

There are AI filter in each A servo and inv_AA, inv_DAA filters in CINV servo, but it's doesn't work correctly yet.

 These aren't servos. What he means is that he's changed some filters in the real time calibration screens so as to make the actuation and sensing parts more accurate, but the inversion of the AA filters is not accurate yet.

  381   Fri Mar 14 15:52:07 2008 robConfigurationLSCLSC code change

I've edited the LSC code to send different signals to the ASS box. Now, instead of the previously selected error signals deemed to be acceptable for the Alignment Sensing and Stabalization system, it sends the LSC control signals for each suspension to the ASS box (in its new incarnation as the Adaptive Susurration Subtraction system). These are the signals after the output matrix, and also after the LSC-[SUS] filter modules.
  386   Thu Mar 20 16:06:27 2008 robConfigurationLSCLSC code change

I changed the LSC code again. I noticed that when turning off the LSC (e.g., going from LA to OFF), the cpu time would jump from ~50 to ~80, and irrevocably de-sync all the SUS controllers. This was because turning off the LSC would suddenly zero the inputs to the decimation filters that send information to the ASS box, which for some reason greatly increases the computation time of the iir filter function call. I changed the code so that these inputs are never zeroed. The ASS receives inputs from the LSC all the time now.

I also noticed that the ASS machine was running in ~2400 usec. Yes, 2,400 microseconds. I don't know how long it's been doing that, but I restarted it. Immediately after restart, it ran at 1700 microseconds. After using the "RESET" field in the adaptOnline code, that dropped to ~100 usec. Now it's not doing any adaptive filtering, as I don't know what the good settings are and no-one has been elogging their IFO work the last few days.
  1457   Tue Apr 7 21:39:57 2009 YoichiConfigurationComputersLSC code recompiled with a fix for denormalization problem
This is not my work but I will put it for the record.

A few days ago, Rob recompiled the LSC code with the fix of the denormalization problem provided by Alex.
Since then, the LSC code has been working fine. I recognize that c1lsc is now less loaded.

I believe Rob only recompiled the LSC code, so there could still be the problem in the suspension controllers.
  1460   Wed Apr 8 18:18:33 2009 ranaConfigurationComputersLSC code recompiled with a fix for denormalization problem
Below is the link to the anti-denormalization technique that Rolf and Alex implemented at the sites,
that was pointed out by Chris Wipf from MIT:

http://www.musicdsp.org/files/denormal.pdf
  3995   Tue Nov 30 12:25:08 2010 josephbUpdateCDSLSC computer to chassis cable dead

Problem:

We seemed to have a broken fiber link for use between the LSC and its IO chassis.  It is unclear to mean when this damage occurred.  The cable had been sitting in a box with styrofoam padding, and the kink is in the middle of the fiber, with no other obvious damage near by.  The cable however may have previously been used by the people in Downs for testing and possibly then.  Or when we were stringing it, we caused a kink to happen.

Tried Solutions:

I talked to Alex yesterday, and he suggested unplugging the power on both the computer and the IO chassis completely, then plugging in the new fiber connector, as he had to do that once with a fiber connection at Hanford.  We tried this this morning, however, still no joy.  At this point I plan to toss the fiber as I don't know of any way to rehabilitate kinked fibers.

Note this means that I rebooted c1sus and then did a burt restore from the Nov/30/07:07 directory for c1suspeics, c1rmsepics, c1mcsepics.  It looks like all the filters switched on.

Current Plan:

We do, however, have the a Dolphin fiber which originally was intended to go between the LSC and its IO chassis, before Rolf was told it doesn't work well that way.  However, we were going to connect the LSC machine to the rest of the network via Dolphin.

We can put the LSC machine next to its chassis in the LSC rack, and connect the chassis to the rest of the front ends by the Dolphin fiber.  In that case we just need the usual copper style cable going between the chassis and the computer.

 

  9312   Wed Oct 30 00:02:25 2013 JenneUpdateLSCLSC demod boards need some thought

As we are meditating on things to look at for PRMI + 2 arms, Rana brought up the question of the demod board situation. 

We then found this table on the wiki (LSC demod boards) that indicates that all of the demod boards were originally given lowpass filters, no matter the demodulation frequency.  Back in September, I switched out the low pass filter for a bandpass filter in POP110, and put in the same bandpass when putting together AS110 (elog 9100).  So, the 11MHz diodes are probably okay with lowpasses, and the 110 diodes are okay, but we need to think about all the other ones. 

We should probably do a first guess by putting in a bandpass filter, but then simulate and measure to figure out what our requirements are for attenuation at the non-demodulation frequencies for each board.

The SXBPs from Minicircuits look pretty good, but there are lots of options on their website.

 

For tonight, Rana has put a coax 100 MHz highpass filter on the input to the REFL165 demod board.

  9316   Wed Oct 30 03:33:17 2013 RanaUpdateLSCLSC demod boards need some thought

 

 0309.png

I worked on the script SPAG4395A.py tonight with Masayuki's help. This sets up the parameters on the Agilent 4395A and then acquires the spectrum data. It had a couple of bugs before: no matter what channel you requested, you always got channel R. It also would disobey any requests to reduce the attenuation and left the Auto Atten ON. The version now in the SVN allows you to choose the channel and the attenuation.

It then makes this plot using matplotlib. The attached image is from the REFL165 pickoff at a time tonight when the arm powers were ~5-10. I have converted the spectrum from RF electrical Watts into Volts (V = 50*sqrt(W)). To go from the analyzer input to the demod board input we should scale this spectrum by a factor of ~15 (to account for the 20 dB from the coupler and the 3 dB of the splitter and a little more for losses). On the oscilloscope we see Vpp ~5 mV, so that's ~75 mVpp at the output of the BBPD which we're using for REFL165. Perhaps we can handle another factor of ~2-3 ? I'm not sure what we have in terms of linearity measurements on this thing.

EDIT: Evan is right, its V = sqrt(50*W), not V = 50*sqrt(W). ignore y-axis above

  14313   Wed Nov 21 09:59:26 2018 gautamUpdateLSCLSC feedforward block diagram

Attachment #1 is a block diagram depicting the pathway by which the vertex DOF control signals can couple into DARM (adapted from a similar diagram in Gabriele's Virgo note on the subject). I've also indicated some points where noise can couple into either loop. In general, there are sensing noises that couple in at the error point of the loop, and actuation noises that couple in at the control point. In this linear picture, each block represents a (possibly time varying) transfer function. So we can write out the node-to-node transfer functions and evaluate the various couplings.

The motivation is to see if we can first simulate with some realistic noise and time-varying couplings (and then possibly test on the realtime system) the effectiveness of the filter denoted by "FF" in canceling out the shot noise from the auxiliary loop being re-injected into the DARM loop via the DARM sensor. Does this look correct?

Attachment 1: IMG_7173.JPG
IMG_7173.JPG
  14326   Fri Nov 30 19:37:47 2018 gautamUpdateLSCLSC feedforward block diagram

I wanted to set up an RTCDS model to understand this problem better. Attachment #1 is the simulink diagram of the signal flow. The idea will be to put in the appropriate filter shapes into the various filter blocks denoting the DARM and auxiliary DoF plants, controllers and actuators, and then use awggui / diaggui to inject some noises and see if in this idealized model I can achieve good subtraction. Then we can build up to applying a time varying cross coupling between DARM and the vertex DoF, and see how good the adaptive FF works. Still need to setup some MEDM screens to make working with the test system easier.

I figured c1omc would be the least invasive model to set this upon without risking losing any of our IR/green alignment references. Compile and install went smooth, see Attachment #2. The c1omc model was clocking 4us before, now it's using 7us.

Attachment #3 shows the top level of the OMC model, while Attachment #4 shows the MEDM screen.

* Note to self: when closing a loop inside the realtime model, there has to be a delay block somewhere in the loop, else a compilation error is thrown.

Attachment 1: LSC_FF_tester.png
LSC_FF_tester.png
Attachment 2: Screenshot_from_2018-11-30_19-41-07.png
Screenshot_from_2018-11-30_19-41-07.png
Attachment 3: Screenshot_from_2018-12-10_15-31-23.png
Screenshot_from_2018-12-10_15-31-23.png
Attachment 4: SimLSC.png
SimLSC.png
  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.)

  8422   Mon Apr 8 10:19:46 2013 JenneUpdatePSLLSC left enabled

 

 Note: The TRY PD isn't installed and normalized properly yet, so the IFO OVERVIEW screen indicates lock for the Yarm constantly, which is not true.  Hopefully in the next day or so the screen will be back to telling the truth.

Also, the LSC Locking was left ENABLED (presumably over the weekend).   This is not so good.  It can kick optics around, so we should all take a look when we walk through the control room, and if no one is locking, please disable the LSC master switch. 

  5495   Wed Sep 21 02:49:39 2011 KeikoSummaryLSCLSC matrices

I created 3 kinds of LSC matrices, PRMI condition with carrier resonant in PRC, PRMI condition with SB resonant in PRC, and DRMI with SB resonant in PRC. The matrices are with AS55 and REFL11 which are used for locking right now. The signal numbers are written in log10, and the dem phases are shown in degrees.

From CR reso PRMI to SB reso PRMI, demodulation phases change  ----

 

PRMI - Carrier resonant in PRC

 

            PRCL      MICH  SRCL

REFL11 7.7079 2.9578 0
REFL33 5.2054 3.2161 0
REFL55 7.7082 2.9584 0
REFL165 3.9294 2.5317 0
AS11 1.0324 3.5589 0
AS33 1.0286 1.6028 0
AS55 1.1708 4.2588 0
AS165 1.1241 0.9352 0
POP11 2.8015 -1.3331 0
POP33 0.2989 -1.6806 0
POP55 2.8017 -0.6493 0
POP165 -0.9769 -2.3708 0
POX11 3.7954 -0.3363 0
POX33 1.293 -0.7058 0
POX55 3.796 0.355 0
POX165 0.0187 -1.3837 0
       
Dem Phase      
REFL11 3 179 0
REFL33 165 -172 0
REFL55 13 170 0
REFL165 86 177 0
AS11 -32 73 0
AS33 176 -72 0
AS55 -41 12 0
AS165 -7 146 0
POP11 -11 -116 0
POP33 124 147 0
POP55 -54 -146 0
POP165 -117 -25 0
POX11 -87 15 0
POX33 -105 -80 0
POX55 -76 16 0
POX165 180 -91 0

PRMI - SB resonant in PRC

SB reso PRMI    
  PRCL MICH SRCL
REFL11 7.6809 5.2777 0
REFL33 5.2465 3.1565 0
REFL55 7.2937 5.589 0
REFL165 4.3892 2.6857 0
AS11 1.3123 3.545 0
AS33 0.9331 1.6022 0
AS55 1.7425 4.0514 0
AS165 1.5838 1.1344 0
POP11 2.7745 0.3791 0
POP33 0.3401 -1.7392 0
POP55 2.3872 0.6904 0
POP165 -0.5171 -2.2279 0
POX11 3.7684 1.3574 0
POX33 1.3341 -0.7664 0
POX55 3.3815 1.6688 0
POX165 0.4785 -1.2163 0
       
Dem Phase
     
REFL11 155 -115 0
REFL33 -8 3 0
REFL55 91 -178 0
REFL165 -62 28 0
AS11 109 62 0
AS33 -39 99 0
AS55 13 -38 0
AS165 -155 168 0
POP11 141 -128 0
POP33 -48 -38 0
POP55 24 115 0
POP165 95 -176 0
POX11 65 155 0
POX33 83 95 0
POX55 2 92 0
POX165 32 123 0

DRMI - SB resonant in PRC

REFL11 7.6811 5.0417 4.2237 
REFL33 5.2751 4.1144 3.7766
REFL55 7.2345 7.0288 6.6801
REFL165 4.3337 4.1266 3.7775
AS11 1.1209 3.512 0.9248
AS33 0.9159 1.6323 0.7971
AS55 2.6425 5.3915 2.5519
AS165 2.6423 2.4881 2.3272
POP11 2.7747 0.1435 -0.6846
POP33 0.3687 -0.7849 -1.122
POP55 2.3244 2.1302 1.7815
POP165 -0.5833 -0.8 -1.1548
POX11 3.7676 3.261 0.8086
POX33 1.3896 0.2372 0.2333
POX55 3.4619 3.0097 3.1326
POX165 0.782 0.6668 0.4357
                        
Dem Phase
     
REFL11 154 -16 4
REFL33 -5 12 51
REFL55 129 -166 -123
REFL165 -23 40 83
AS11 132 79 69
AS33 -92 -127 -83
AS55 -33 -55 -5
AS165 154 179 -144
POP11 141 -29 -9
POP33 -46 -27 12
POP55 62 127 170
POP165 135 -161 -117
POX11 64 -102 -83
POX33 85 143 118
POX55 57 103 124
POX165 99 155 -164

 

 

  10904   Thu Jan 15 14:28:14 2015 JenneUpdateLSCLSC model change idea

Something that kind of drives me crazy with our current LSC model setup is that I can't make "finished" error signals before blending them.  The blending happens before the normalization matrix, and there is no place to put an offset to help match a new error signal to the current offset.  So.  While I'm sure this is not going to be immediately popular, here's a cartoon of a proposed model change to the LSC. 

The most important difference between this and the ramping matrix that is used at the sites is that you can put in offsets before the blend.  Also useful is the fact that the normalization can happen before the blend.  This proposal would make the LSC input matrix  and the normalization matrix have twice as many rows, and add an extra "selector matrix" just before the triggering at the error point of the loops. 

I've only drawn one degree of freedom in my cartoon, but assume that they all have the same capability (maybe we don't have to do XARM, YARM and MC this way).  One row is currently being used for the error signal, while the other row is just used to prep a new singal.  For a first transition (say, ALS to DC transmission), maybe the ALS signals are on row 1, and the DC trans is on row 2.  Once the transition is complete, row 1 is available to prep for the next transition (such as AS55Q).

 

Thoughts?  Is there a better way to achieve what I'm going for here?

Attachment 1: SwitchableErrorSignalProposal_Jan2015.pdf
SwitchableErrorSignalProposal_Jan2015.pdf
  10910   Fri Jan 16 03:31:35 2015 JenneUpdateLSCLSC model change implemented

Okay, it has taken me almost exactly 12 hours (with a dinner break), but I have implemented this change.

Everything was svn-ed before I did things, and then again afterward.

Here is the "before" screenshot of the LSC model:

And here is afterward:

If you look extra carefully, you will see that it matches my proposal from http://nodus.ligo.caltech.edu:8080/40m/10904 .  I have made the change for DARM, MICH, PRCL, SRCL and CARM.  I did not alter XARM, YARM or MC.  Also, the CESAR stuff was taken out of the CARM area, since this is now a more generalized version of the same thing.


I have also checked and modified all of the scripts that I could think of, as well as all of the ifoconfig burt .req and .snap files that I could think of.  I also ran the carm_cm_up.sh script once, and it seems to work fine.  All of the transition scripts that are listed below (which are the only ones used currently in the sequence) now use the new error signal blending scheme.

Scripts:

  • Lock_ALS_CARMandDARM.py
  • ALSfindIRresonance.py
  • ALSwatch.py
  • carm_cm_down.sh
  • carm_cm_up.sh
  • CheckPRMIlock.py
  • Transition_MICH_REFL33Q_to_ASDC.py
  • Transition_CARM_ALS_to_TransInvSqrt.py
  • Transition_DARM_ALS_to_DCtrans.py
  • UGFup.py
  • UGFdown.py

Burts (listed are the .req files, but I also checked the .snap files, hand-editing the matrix element numbers where needed if I wasn't in the right config to do a save):

  • C1configure_Yarm.req
  • C1configure_YarmALS.req
  • C1configure_Xarm.req
  • C1configure_XarmALS.req
  • C1configure_CARM.req
  • C1configure_DARM.req
  • C1configure_PRM_forCARMdarm.req
  • C1configure_PRM_SBres.req
  • C1configure_PRM_Carr.req
  • C1configure_PRY.req
  • C1configure_DRM.req
  • C1configure_SRM.req

I also modified the screens for the input matrix and for the normalization matrix.  I created a new screen for the final blending matrices (which are all 2x1's), and I also modified the LSC_OVERVIEW screen. 

The input matrix and normalization matrix screens have colored bars that tell you whether a row is in use or not.  If the background to the row is the blue of the whole screen, that row is not being used.

The LSC screen has new hand-modified Kissel Buttons.  I wanted to show the total PD error signal that is being used, regardless of what row (A or B) it is on at that time.  So, I have collapsed the rows so that DARM_A and DARM_B are overlapped, even though they are actually rows 1 and 2 of the matrix.  The PD should only show up green on the LSC screen if that row is in use (so, if you are prepping a row, but aren't using it yet, you won't see those elements in the matrix).  Anyhow, the point is that the LSC overview part of things shouldn't look any different than before.


Brain not working anymore now that it's ~4am, but I need to rethink and recheck to make sure that the PD whitening triggering is still okay and working.  Or maybe we can remove it, and just include that in the scripts, as Rana has been suggesting for ages.  Thoughts for tomorrow.

  10914   Fri Jan 16 18:46:15 2015 KojiUpdateLSCLSC model change implemented

Was the screen modified directly on LSC_OVERVIEW.adl?
Even if so, that's OK. I'll incorporate the change to the screen making script once I'm back.

  10915   Fri Jan 16 20:01:32 2015 JenneUpdateLSCLSC model change implemented

Nope, I used the script.

Yesterday's changes were mostly to the generateLSCscreen/C1LSC_OVERVIEW_INPUT_MATRIX.adl sub-screen.  The UGF servos were added earlier in the week to the LSC screen in the generateLSCscreen/C1LSC_OVERVIEW_SERVOS.adl sub-screen.

  10923   Tue Jan 20 15:09:01 2015 JenneUpdateLSCLSC model change implemented

 

Quote:

Brain not working anymore now that it's ~4am, but I need to rethink and recheck to make sure that the PD whitening triggering is still okay and working.  Or maybe we can remove it, and just include that in the scripts, as Rana has been suggesting for ages.  Thoughts for tomorrow.

LSC whitening triggering was not working, because of the implementation of the double-rows for the input matrix.  I have modified the c-code that looks at the input matrix and triggers, and decides when to turn on the PD whitening, so that it now works.

  9820   Thu Apr 17 01:01:02 2014 JenneUpdateLSCLSC model modifications

Last night, EricQ and I were concerned that we might need some CARM UGF servoing, so I added a UGF servo block, copied from the aLIGO LSC model, to our LSC model.  The block is inline with the CARM servo, after the output triggering, just before the output matrix.  Q put together some screens, which are accessible from the main LSC screen. 

The model is compiled and running.  We didn't get very far in testing it though before Koji pointed out that it is a slow solution, and not a fast one like we were searching for.  We were hoping to deal with the momentary power buildup, and thus optical gain change, as the arms flash close to resonance.  The UGF servo will not work nearly that fast though.  We may want it for slow UGF servo-ing, but it's not the solution to what Q and I were thinking about yesterday.  Regular ol' dynamic normalization is closer to the right answer for this.

In tonight's activities, Koji and I found that we probably want a CESAR block for DARM as well as CARM, so that we can independently normalize AS55Q. 

To solve the DARM oscillation issue from last night (that I discovered this evening when I finally looked at the time series data), we may want to implement a DARM UGF servo.  For tonight, as we reduced the CARM offset and started seeing gain peaking in the DARM spectra, I hand-reduced the DARM gain.

 

  9766   Mon Mar 31 13:26:23 2014 manasaUpdateLSCLSC model modified

I have included Yarm CESAR to the LSC model. It was just a copy paste of the Xarm CESAR. Since we are now meditating about implementing CCESAR and DCESAR, I did not run or install the model as yet.

  5812   Fri Nov 4 15:26:54 2011 JenneUpdateLSCLSC model recompiled

I moved the place where we take the OAF Degree of Freedom signals from - now it's the error point rather than the feedback for DARM, CARM, MICH, PRCL, SRCL, XARM and YARM.  I didn't do anything to MCL.

While trying to compile, there was something wrong with the lockins that were there...it complained about the Q OUTs being unconnected.  I even reverted to the before-I-touched-it-today version of c1lsc from the SVN, and it had the same problem.  So, that means that whomever put those in the LSC model did so, and then didn't check to see if the model would compile.  Not so good.

Anyhow, I just terminated them, to make it happy.  If those are actually supposed to go somewhere, whoever is in charge of LSC lockins should take a look at it.

Also, as Mirko mentioned in the previous elog 5811, we wanted to calculate the effect on the MC without actuating, so we put in a new summing point and a filterbank so we have testpoints.

LSC model recompiled.

OAF model recompiled.

FB restarted because of the new channels added to OAF.

  5832   Mon Nov 7 15:15:21 2011 JenneUpdateLSCLSC model recompiled

Quote:

I moved the place where we take the OAF Degree of Freedom signals from - now it's the error point rather than the feedback for DARM, CARM, MICH, PRCL, SRCL, XARM and YARM.  I didn't do anything to MCL.

While trying to compile, there was something wrong with the lockins that were there...it complained about the Q OUTs being unconnected.  I even reverted to the before-I-touched-it-today version of c1lsc from the SVN, and it had the same problem.  So, that means that whomever put those in the LSC model did so, and then didn't check to see if the model would compile.  Not so good.

Anyhow, I just terminated them, to make it happy.  If those are actually supposed to go somewhere, whoever is in charge of LSC lockins should take a look at it.

Also, as Mirko mentioned in the previous elog 5811, we wanted to calculate the effect on the MC without actuating, so we put in a new summing point and a filterbank so we have testpoints.

LSC model recompiled.

OAF model recompiled.

FB restarted because of the new channels added to OAF.

 After Rana pointed out the errors of our ways, we reverted all of these changes.

  5833   Mon Nov 7 15:43:25 2011 jamieUpdateLSCLSC model recompiled

Quote:

While trying to compile, there was something wrong with the lockins that were there...it complained about the Q OUTs being unconnected.  I even reverted to the before-I-touched-it-today version of c1lsc from the SVN, and it had the same problem.  So, that means that whomever put those in the LSC model did so, and then didn't check to see if the model would compile.  Not so good.

Anyhow, I just terminated them, to make it happy.  If those are actually supposed to go somewhere, whoever is in charge of LSC lockins should take a look at it.

 This was totally my fault.  I'm very sorry.  I modified the lockin part to output the Q phase, and forgot to modify the models that use that part appropriately.  BAD JAMIE!  I'll check to make sure this won't bite us again.

  9225   Wed Oct 9 17:27:35 2013 JenneUpdateLSCLSC model sensing matrix upgrades

The modifications to the LSC model are now complete, and the new model has been compiled, installed, and is running. The sensing matrix lockins are all in the c1cal model.  Masayuki is locking right now, so so far, things appear to be back to normal.

The longer version of the story, with all the detours and hiccups:

After several tries of deleting the GoTo and From flags / tags in the lockin area of the LSC model, and continually getting the "something is not connected" errors, I gave up and just drew several long lines.  So, in the new Sensing Matrix block (which is actually in c1cal, not c1lsc, but that's a story for the next paragraph), we should eventually make things back to the more clean flags situation, but for right now, it's working, with lots of lines everywhere.  I've tried to be very organized and clear about what lines go where, so that it's easy to see what's going on.

I eventually was able to compile c1lsc, and then installed it, and restarted the model.  Adding in 5x the lockin modules (we had 27, but now we have 5x27, so that we can look at the sensing matrix elements for every degree of freedom, and every photodiode, all at the same time) was too much for the poor lsc cpu.  I was consistently getting over 70usec per cycle, and was hitting a max of 77usec for the lsc cpu.  Both of those numbers are greater than the allowed 60usec.  So, I made the decision to put the whole sensing matrix / lockin stuff into the calibration model.  This means that I have 27+5 more IPC signals than I used to, but so far things seem to be okay (no rigorous testing yet).  (27 to send the 27 PD inputs over to the cal model, and another 5 to send the oscillator "clocks" from the cal model to the lsc model.)  The lsc model is now running faster than before (because there were 27 lockin modules in the model), at 24-28 usec, and the cal model is running at 39usec.

All seemed well and good, both the lsc and cal models compiled, but the lsc burt restore wasn't working.  Restarting the model did not successfully do a burt restore, and when I tried several different .snap files from today, and other times this month using burtgooey, I kept getting "NOT OK", and numbers weren't being restored into the epics channels.  A very few settings were restored, but most were not.  I ended up copying a .snap file from a few hours ago into a separate directory, then went in and by-hand removed all the lines referring to now non-existant lockin channels.  Burtgooey still told me "NOT OK", but settings seem to be restored, so I think it's okay.  I have not confirmed each and every one of the 10,000+ channels to ensure that the number is the same as the one in the .snap file, but as I glance around in the LSC screen and its dependants, all the numbers and buttons look about right.  

After all this stuff, Masayuki is locking both arms simultaneously in IR, as he prepares to test some new ALS scripts, so things seem okay for now.

  9222   Tue Oct 8 16:56:38 2013 JenneUpdateLSCLSC model sensing matrix upgrades in progress

I have modified the LSC model (the currently-running model is checked into the svn), but it is not compiling for me.  So, if you need to make changes to it, be careful, and probably save my version off to the side, and checkout the latest svn version.  (I don't foresee anyone needing to modify this model any time soon though).

The change that I'm trying to make is adding several more lockin setups, so that we can measure the sensing matrix elements for several degrees of freedom simultaneously. 

Right now, the error that I'm getting is the frustrating "something isn't connected" error, even though if you look in the model, the part that it mentions is fully connected.  Usually the solution to this is to disconnect and reconnect everything, so I'll work on that after I return to the lab in a bit.

  9109   Thu Sep 5 01:55:29 2013 JenneUpdateLSCLSC model upated to have AS110 channels, violin filter triggering

I have modified the c1lsc model so that I have access to the AS110 channels in the triggering and power normalization matrices. 

I also put in a few blocks so that we can have triggering on the violin notches that we moved to the LSC model a week or so ago. 

Here is my svn comment, so I don't have to retype things:

2 changes:  AS110 channels added, and Violin filter triggers added.

AS110:     We recently installed a    new demod board    and PD for an AS110 signal.  Since we will not    be using AS11 in the forseeable    future,    the AS110 demod    board outputs use the former AS11 channels.  I    have left the AS11 channels in the model so that we can easily    add them back if we want to, but they are grounded rather than    connected to the ADC.  I've added digital demodulation for AS110, power normalization,    and then added the I&Q signals to both the trigger matrix and the main    power normalization matrix.  NOTE that these slide the matrix columns around.    Since the AS110    is also    using the former AS11 whitening    channels, swapped those on the    BIO block also.

Violins:  Recently, Rana and I moved the SUS LSC violin    filters    from the individual suspension    models over to the LSC model.  Giving every optic every    optics' violin    notch helps eliminate bad cross-coupling between servo loops.  Here, I have enabled triggering    for these notches, so that the violin filters can come on after a cavity is locked.  Since the    filter banks SHOULD BE THE SAME    for all LSC_SUS banks,    the "mask" is common to    all optics.

I also edited several medm screens, to show the new changes:  the lsc overview screen has a button to the violin notch triggering screen, in addition to being able to get to the new screen from the regular triggering matrix screen.  I made the trigger and normalization matrix screens bigger, since there are now 2 new columns. 

I added AS110 to both the LSCoffsets script, and Masayuki's new, better, LSCoffsets2.py. 

I added new lines to the .req files for the ifo configure burt restores for the new matrix columns, and the violin triggering.

I restored, checked out, and saved the Xarm, Yarm, MICH, PRM_sb, and DRM configurations. 

 


I tried locking the DRMI, but haven't really been successful.  I'm not 100% sure how to do the phasing for AS110, so that could be a problem.  For POP, I can watch POPDC to see if something is a carrier or a sideband flash, but I don't have something quite as convenient at the AS port.  I have set the AS110 phase to 60 degrees for now, since during free swinging DRMI flashes, it looks like most of the buildup is in the I phase with 60 degrees.  Even with the same configurations as a week or so ago, I'm not getting much more than ~1 second locks.

I also tried locking the SRMI, but am not getting anything at all.  I think I need to go back to simulation-land to figure out what good signals might be.

 


Other thoughts:

Stefan modified the LSC filter module triggering blocks, so now we have a new epics variable, "_INVERT", which sends the trigger through a NOT or not.  I think that we want to keep this variable set to 0 to be the same as things were, but I do need to expose this new variable on the screens.

The trigger and normalization matrices pictured on the LSC overview screen need to be expanded by the 2 new columns.  The actual matrix screens are good, but I forgot to fix up the little Kissel buttons.

When I have a free swinging SRMI, MICH and SRCL should have the same sign for the gain, if I'm using AS55 I&Q for locking.

LLO is using REFL 9I for SRCL, and ASDC for MICH for the SRMI, but I don't have any REFL beam with a misaligned PRM, so I don't think I can copy what Den and Lisa did on Monday night.

I have figured out / rediscovered why the "sqrt" buttons on the power normalization screen aren't restored when you restart the LSC model - They are controlled by momentary epics records, which go to embedded c-code to do some toggling.  I don't know yet of a good way to save the configuration of these guys for burt restore-type restoration.  This will be a problem for anything that is using these toggle c-codes.

  4912   Wed Jun 29 14:43:12 2011 KojiUpdateLSCLSC model updated

LSC model has been updated and running,

- Now the power and signal recycling cavity lengths are named "PRCL" and "SRCL" in stead of three letter names without "L".

- Names for the trigger monitor were fixed. They are now "C1:LSC-DARM_TRIG_MON", etc., instead of "...NORM"

- Channel order of the DC signals for PDDC_MTRX and TRIG_MTRX were changed.

It was "TRX, TRY, REFL, AS, POP, POX, POY" but now "AS, REFL, POP, POX, POY, TRX, TRY".

We should change the locking script to accomodate these changes.

  4962   Tue Jul 12 11:52:54 2011 Jamie, SureshUpdateLSCLSC model updates

The LSC model has been updated:

Binary outputs to control whitening filter switching

We now take the filter state bit from the first filter bank in all RF PD I/Q filter banks (AS55_I, REFL11_Q, etc) as the controls for the binary analog whitening switching on the RF PD I/Q inputs. The RF_PD part was also modified to output this control bit. The bits from the individual PDs are then combined into the various words that are written to the Contec BO part.

Channel mapping updated/fixed to reflect wiring specification

Yesterday Suresh posted an updated LSC wiring diagram, with correct channel assignments for the RF PD I/Q and DC inputs.  Upon inspection of the physical hardware we found that some of LSC the wiring was incorrect, with I/Q channels swapped, and some of the PDs in the wrong channels.  We went through and fixed the physical wiring to reflect the diagram.  This almost certainly will affect the EPICS settings for some of the input channels, such as offsets and RD rotations.  We should therefore go through all of the RF inputs and make sure everything is kosher.

I also fixed all of the wiring in the LSC model to also reflect the diagram.

Once this was all done, I rebuilt and restarted the LSC model, and confirmed that the anti-whitening filter banks in the PD input filter modules were indeed switching the correct bits.  I'll next put together a script to confirm that the LSC PD whitening is switching as it should.

 

  1214   Fri Jan 2 18:49:54 2009 YoichiUpdateLSCLSC modulation frequencies adjusted
I noticed that the IFO did not lock in the MICH configuration.
This was because AS166Q signal was too small.
The demodulation phase seemed not right, i.e. the I-phase signal was larger than Q.
I suspected that the 166MHz modulation frequency was not exactly on the MC FSR, since I just
recovered the number written on the Marconi after the power failure.
I measured the optimal frequency by the method explained in elog:752.
It was 165981500Hz, which is pretty close to the number Rob measured in elog:952, but significantly different from
the label on the Marconi.
I set the frequencies of all the MARCONIs accordingly and updated the labels.

After this, the AS166 demodulation phase was still not good enough (the Q and I signals were about the same).
So I rotated the phase by 45deg. In principle, this should set the demod-phase right for DARM too. Is it correct, Rob ?
I also adjusted the PD offsets. After those adjustments, MICH locks stably with a slightly increased gain (20 as compared to 10 before).
  8729   Wed Jun 19 22:38:15 2013 JenneUpdateComputer Scripts / ProgramsLSC normalization sqrt_mon channels added to conlog

 

 Something has happened that all of the C1:LSC-dof_NORM_SQRT_ENABLEs are disabled, but normally some are enabled and others are not.

In the hopes that miraculously this change happened after Jamie restarted the conlog this afternoon, I checked the conlog.  These channels, however, were not recorded. 

Using the instructions on the conlog wiki page, I added the _MON channels to the conlog list.  The one snag I hit was that the medm screen referred to in the wiki isn't usable if you open it by hand using the medm gui, since it needs to know what IFO you're at to fill in the macro expansion variables.  To remedy this, I changed the "FE STATUS" button on the sitemap to "CDS", and added the conlog screen to the list of options.  

Now I see that the conlog at least knows about these channels, for future reference.

  9868   Mon Apr 28 13:18:18 2014 JenneUpdateLSCLSC offsets script modified

Quote:

The weird jumps at the beginning of each TRX peak are due to the triggered switching between the Thorlabs trans PD and the QPD trans PD.  Clearly we need to work on their relative normalizations.  There are also little jumps after each peak as the triggering sends the signal back to the Thorlabs PD.

 I was unhappy with the discontinuities between the Thorlabs and QPD versions of our transmitted light powers.  I realized that in the olden days, we just used the Thorlabs PD, and we set the no-light offset in the LSC version of the TR[x,y] filter banks.  However, now that we have brought the QPDs back, we are setting the dark offsets in the end suspension models, so that the signal chosen by the trigger already has its offset taken care of before we send it to the LSC model. 

Anyhow, having the offsets script try to put a value in the C1:LSC-TR[x,y]_OFFSET was giving us an extra offset and then when we did the normalizations, the numbers came out all wrong.  So.  I have removed the C1:LSC-TR[x,y] filter banks from the offset list, since they were made redundant. 

I have redone the normalizations for both arms (after running the ASS scripts).  I checked by watching the _OUT16 versions of the Thorlabs and QPD diodes before the triggering happens, and as I put offsets into the LSC servos to change the transmitted power, the diodes both change in the same way.  So, we'll have to see if this holds true for more than just values 0-1 the next time we lock, but hopefully it won't need changing for a while.

  4644   Thu May 5 15:33:37 2011 steveConfigurationRF SystemLSC rack

New right angle PVC front panel with SMA bulkhead connectors are in place. The connections are still lose. It is ready for Suresh to finalise his vision on it.

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  4768   Fri May 27 17:52:53 2011 steveUpdateLSCLSC rack cables strain relieved & labeled

LSC rack 1Y2 cables are strain relieved and labeled. Spare and/or obsolete cables are laid out on the top of the beam tube and on the outside of the rack.

The POY 110 MHZ demodboard has a very touchy position in the VME crate. Watch out for it! It has to be fixed.

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