This is definitely a nice magic to know as the rebooting causes too much hustles.

Also, you and I should spend an hour in the afternoon to add the suspension swtches to the burt requests.

So apparently with the current Dolphin drivers, when one of the nodes goes down (say c1lsc), it causes all the other nodes to freeze for up to 20 seconds.

This 20 seconds can force a model to go over the 60 microseconds limit and is sufficiently long enough to force the FE to time out.  Alex and Rolf have been working with the vendors to get this problem fixed, as having all your front ends go down because you rebooted a single computer is bad.

[40184.120912] c1rfm: sync error my=0x3a6b2d5d00000000 remote=0x0
[40184.120914] c1rfm: sync error my=0x3a6b2d5d00000000 remote=0x0
[44472.627831] c1pem: ADC TIMEOUT 0 7718 38 7782
[44472.627835] c1mcs: ADC TIMEOUT 0 7718 38 7782
[44472.627849] c1sus: ADC TIMEOUT 0 7718 38 7782
[44472.644677] c1rfm: cycle 1945 time 17872; adcWait 15; write1 0; write2 0; longest write2 0
[44472.644682] c1x02: cycle 7782 time 17849; adcWait 12; write1 0; write2 0; longest write2 0
[44472.646898] c1rfm: ADC TIMEOUT 0 8133 5 7941


The solution for the moment is to start the computers at exactly the same time, so the dolphin is up before the front ends, or start the models by hand after the computer is up and dolphin running, but after they have timed out.  This is done by:

sudo rmmod c1SYSfe

sudo insmod /opt/rtcds/caltech/c1/target/c1SYS/bin/c1SYSfe.ko

Alex and Rolf have been working with the vendors to get this fixed, and we may simply need to update our Dolphin drivers.  I'm trying to get in contact with them and see if this is the case.

80 degrees is too uncomfortable in the control room so I turned on the AC. The set point is 74F.

[Rana and Kevin]

I measured the optical transfer function of POY and fit the data using LISO. The fit can be found at http://lhocds.ligo-wa.caltech.edu:8000/40m/Electronics/POY. POY was missing the RF cage and back cover so I took those parts from AS55 in order to make these measurements.

POY does not have the unwanted oscillations at 225 MHz that POX has. Attachment 1 shows the transfer functions of POX and POY.

To measure the transfer functions, I used a 50/50 beam splitter to send half the light from an AM laser to POY and half the light to a New Focus 1611 reference photodiode. The transfer function for POY was measured as the transfer function of the signal from POY divided by the signal from the 1611. When I was measuring the transfer function for POX, I failed to ensure that the photodiodes were operating linearly. Before making the measurements for POY, I varied the RF power modulating the AM laser and recorded the magnitude of the transfer function at the 11 MHz peak. Attachment 2 shows these values. The measurements for POY were made in the linear region at an RF power of -10 dBm. The measurements for POX were made at 0 dBm and were most likely not in the linear region for POX.

Experiment in the night of Jan 26.

o The arm was locked for the IR beam and was aligned for it.
o The green was aligned to the arm
o The beat freq was observed with the RF analyzer and the webcam.
o Engaged the ALS servo
o Compared the fluctuation of the beat freq with and without ALS
o Scanned the beat freq in order to find an IR resonance

The beat freq was scanned. A resonance for IR was found.
However, the residual motion of the arm was not within the line width of the IR resonance.

 To Do
- Improve the ALS servo (==>Koji)
- VCO noise characterization (==>Suresh is on it)
- Calibrate the PLL feedback (i.e. ALS error) into Hz/rtHz (==>Suresh)
- Calibrate the end green PZT fb into Hz/rtHz (==>Osamu is on it)
- Tuning of the suspension filters to reduce the bounce mode coupling.

DETAILS

o How to lock the arm with IR

• Coarsely align the arm without lock. Transmittion was ~300 with MCTRANS ~40000
• REFL11I is the error signal. unWhiten filter (FM1) should be on.
• Unlock the MC and null the error and the arm trans offset by running the following commands

ezcaservo -g -0.1 -r C1:LSC-REFL11_I_OUTPUT C1:LSC-REFL11_I_OFFSET
ezcaservo -g -0.1 -r C1:LSC-REFL11_Q_OUTPUT C1:LSC-REFL11_Q_OFFSET
ezcaservo -g 0.1 -r C1:LSC-TRX_OUTPUT C1:LSC-TRX_OFFSET

• Confirm the input matrix to pass REFL11I to MC path (why don't we use XARM path...?)

ezcawrite C1:LSC-MTRX_81 1.0

• Servo configuration
  • For acquisition: Gain of 2. Only FM1 (1000:10) has to be on.
  • After the acquisition (TRX>200): The gain is to be changed to 1. FM2 and FM3 can be turned on for the LF boost.
• Actuator matrix: connect MC path to ETMX and MC2

ezcawrite C1:LSC-OM_MTRX_18 1.0
ezcawrite C1:LSC-OM_MTRX_78 1.0

o How to align the green beam

• After the alignment I went the end and aligned the last two steering mirrors.

o The beat freq monitor

• Put the RF analyzer at the RF splitter of the RFPD output.
• Used Zonet webcam (http://192.168.113.201:3037) for the remote monitoring

o How to engage the ALS servo

• Preparation:
  
  • VCO PLL feedback comes to X_FINE path.
  • Put an offset of -850 to cancel too big offset (when the VCO is unlocked)
  • Use Y_FINE channel for the offset addtion. FM1 is 10mHz LPF in order to make the offset smooth.
  • Add X_FINE and Y_FINE by the matrix.
• Control
  
  • Turn off X_FINE out. Leave Y_FINE output turned on.
  • Turn on ETMX ALS path.
  • Servo setting: FM1 1000:30 ON, others OFF, gain1
  • Wait for the beat comes in to the locking range at around 80MHz.
  • If the peak is too far, sweep Y_FINE offset in order to . Or change GCV slow thermal offset to let the beat freq jump.
  • You may have ambiguity of the feedback sign depending on which green has higher freq.
  • After the capture of the ALS lock, increse the gain up to 20. Turn on 0.1:boost at FM3.

o Comparison of the stability of the beat freq (Attachment3)

• The spectra of the VCO PLL feedback was measured.
• First of all, the signal was measured without ALS (blue).
  The PLL lost lock quite frequently, so the careful adjustment of the offset was necessary.Still I think there was slight saturation upconversion.
• Then, the ALS was turned on (red). The gain was 20. This is an in-loop evaluation of the servo. The suppression was ~1000 at 1Hz.

o Beat freq scanning

• The following command was used for the beat note scanning 

ezcastep -- "C1:GCV-YARM_FINE_OFFSET" "5,500"

• Once the IR transmission was found, the scan was stopped.
• Because the resultant rms stability of the arm was not within the line width of the cavity, the smooth resonant curve was not obtained.
• From the shape of the error signal the peak-to-peak displacement (f>1Hz) was estimated to be +/-0.7nm. The dominant displacement
  in the period is 16Hz component.

I modified the generate_master_screens.py script in /opt/rtcds/caltech/c1/medm/master/ to handle changing the MCL (and MC_L) listings to ALS for the two ETM suspension screens and associated sub-screens.

The relevant added code is:

custom_optic_channels = ['ETMX',
{'MCL':'ALS','MC_L':'ALS'},
'ETMY',
{'MCL':'ALS','MC_L':'ALS'}]

for index in range(len(custom_optic_channels)/2):
   if optic == custom_optic_channels[index*2]:
     for swap in custom_optic_channels[index*2+1]:
       sed_command = start_sed_string + swap + "/" + custom_optic_channels[index*2+1][swap] + middle_sed_string + optic + file
       os.system(sed_command)

When run, it generates the correctly named C1:SUS-ETMX_ALS channels, and replaces MCL and MC_L with ALS in the matrix screens.

I calibrated noise spectrum of green lock.

1. Measurement of conversion factor of ADC input from V to ct:

As a preparation, first I measured a conversion factor at ADC input of C1;GCX1SLOW_SERVO1.

It was measured while the output of AI ch6 as the output of C1;GCX1SLOW_SERVO2 with 1Hz, 1000ct(2000ct_pp) was directly connected into AA ch7 as the input of C1;GCX1SLOW_SERVO1. Amplitude at the output at AI ch6 was 616mVpp measured by oscilloscope, and C1;GCX1SLOW_SERVO1_IN1 read as 971.9ct_pp. So the conversion factor is calculated as 6.338e-4[V/ct].

2. Injection of a calibration signal:

When Green laser was locked to cavity with fast PZT and slow thermal, I injected 100Hz, 1000ct EXC at ETMX ASL. The signal was measured at C1:GCX1SLOW_SERVO1_IN1 as 5.314ct_rms. It can be converted into 3.368e-3Vrms using above result, and then converted into 3368Hz_rms using PZT efficiency as 1MHz/V. This efficiency was obtained from Koji's knowledge, but he says that it might have 30% or higher error. If somebody get more accurate value, put it into the conversion process from V to Hz here.

3. Conversion;

Frequency of green f=c/532nm=5.635e14[Hz] is fluctuating with above 3368Hz_rms,so the fluctuation ratio is 3368/5.635=5.977e-12, and it corresponds to length fluctuation of 37.5m. So, cavity fluctuation will be 5.977e-12*37.5=2.241e-10m_rms by 100Hz, 1000ct EXC at ETMX ASL.

4. Results;

Finally, we knew 5.314ct corresponds to 3368Hz and 2.241e-10m, so conversion factor from ct to Hz and ct to m are ;

633.8[Hz/ct] @ C1:GCX1SLOW_SERVO1

4.217e-11[m/ct] @ C1:GCX1SLOW_SERVO1

5. Calibration:

You can measure green noise spectrum at C1;GCX1SLOW_SERVO1_IN1 during lock,  and mutiply above result to convert Hz or m.

This calibration is effective above corner frequency of slow and fast servo around 0.5Hz and UGF of fast servo around 4kHz.

I show an example of calibrated green noise.

Each color show different band-width. Of course this results of calibration cactor does not depend on band-width. Noise around 1.2Hz is 6e-8Hz/rHz. It sounds a bit too good by factor ~2. The VCO efficiency might be too small.

Note that there are several assumptions in this calibration;

1. TF from actual PZT voltage to PZT mon is assumed to be 1 in all frequency. Probably this is not a bad assumption because circuit diagram shows monitor point is extracted PZT voltage directly.

2. However above assumption is not correct if the input impedance of AI is low.

3. As I said, PZT efficiency of 1MHz/V might be wrong.

I also measured a TF from C1:SUS-ETMX_ALS_EXC to C1:GCX1SLOW_SERVO1_IN1. It is similar as calibration injection above but for wide frequency. This shows a clear line of f^-2 of suspension.

Files are located in /users/osamu/:20110127_Green_calibration.

No signal is transmitted from C1:GCV-SCX_ETMX_ALS (on c1gcv) to C1:GCV-SCX_ETMX_ALS (on c1scx)

I can't find RFM definition for ALS channels in c1rfm. Where are they???

As you've correctly noted, the source of the C1:GCV-SCX_ETMX_ALS channels is in the c1gcv model. The first 3 letters of the channel name indicate this (GCV).

The destination of this channel is c1scx, the 2nd 3 letters indicate this (SCX). If it passed through the c1rfm model, it would be written like C1:GCV-RFM_ETMX_ALS.

This particular channel doesn't pass through the c1rfm model, because the computers these two run on (c1ioo and c1scx) are directly connected via our old VMIC 5565 RFM cards, and don't need to pass through the c1sus computer. This is in contrast to all communications going to or from the c1lsc machine, since that is only connected the c1sus machine by the Dolphin RFM. The c1rfm also handles a bunch of RFM reads from the mode cleaner WFS, since each eats up 3-4 microseconds and I didn't want to slow the c1mcs model by 24 microseconds (and ~50 microseconds before the c1sus/c1scx computer switch).

So basically c1rfm is only used for LSC communications and for some RFM reads for local suspensions on c1sus.

As for the reason we have no transmission, that looks to be a problem on c1ioo's end. I'm also noticing that MCL is not updating on the MC2 suspension screen as well as no changes to MC PIT and YAW channels, which suggests we're not transmitting properly.

I rebooted the c1ioo machine and then did a burt restore of the c1ioo and c1gcv models. These are now up and running, and I'm seeing both MCL and ALS data being transmitted now.

Its possible that when we were working on the c1gfd (green frequency divider model) on c1ioo machine we disturbed the RFM communication somehow. Although what exactly, I'm not sure.

I've updated the scan_adls script (currently located in /cvs/cds/caltech/conlog/bin) to look at new location of our medm screens.  I made a backup of the old conlog channel list as /cvs/cds/caltech/conlog/data/conlog_channels.old-2011-01-28.

I then ran the update_chanlist script in the same directory, which calls the scan_adl script.  After about 5 minutes it finished updating the channel list.  I restarted the conlogger just to be sure, and checked that our new model channels showed up in the conlog (which they do).

I have added a cron job to the op340m cron tab to once a day run the update_conlog script at 7am.

Next, I'm working on a HealthCheck script which looks at the conlog channel list and checks to see if channels are actually changing over short time scales, and then spit back a report on possibly non-functioning channels to the user.

The MC WFS have had beam dumps in front of them for the past ~2 weeks, until I could find the appropriate optic to put in the WFS path, to avoid melting the WFS' electronics. 

Koji noted that Steve had a W2-45S in a secret stash near his desk (which Steve later had put into the regular optics storage shelves down the Yarm), so I used that in front of the black hole beam dump on the AS table.  Now the beam is ~1W reflected from the unlocked mode cleaner, and ~100mW goes to the MC REFL PD.  The other 900mW now goes to this W2, and only ~5mW is reflected toward the MC WFS.  Most of the 900mW is transmitted through the window and dumped in the black hole.  There is a ghost beam which is reflected off the back surface of the wedged window, and I have blocked this beam using a black anodized aluminum dump.  I will likely change this to a razor dump if space on the table allows.  I have aligned the beam onto WFS1 and WFS2, although I did not re-align the mode cleaner first, so this alignment of the WFS will likely need to be redone. 

WFS1 has about 2mW incident, and WFS2 has about 3mW incident, when the mode cleaner is unlocked.  I have not yet measured the power incident when the MC is locked, although obviously it will be much smaller.

Except that I might temporarily remove one of the WFS for more quantum efficiency measurements later today, the WFS should be ready to turn back on for alignment stabilization of the mode cleaner. 

Mystery solved!

I removed WFS2 from the AP table (after placing markers so I can put it back in ~the same place) so that I could take some reflectivity as a function of angle measurements for aLIGO WFS design stuff.

I was dismayed to discover, upon glancing at the diode itself, that half of the diode is covered with some kind of oil!!!.  The oil is mostly confined to quadrants 3 and 4, which explains the confusion with their quantum efficiency measurements, as well as why the readback values on the MEDM WFS Head screen for WFS2 don't really make sense. 

The WFS QPD has a piece of glass protecting the diode itself, and the oil seems to be on top of the glass, so I'm going to use some lens tissue and clean it off.

Pre-cleaning photos are on Picasa.

Update:  I tried scrubbing the glass with a Q-tip soaked with Iso, and then one soaked in methanol.  Both of these failed to make any improvement.  I am suspicious that perhaps whatever it is, is underneath the glass, but I don't know.  Rana suggested replacing the diode, if we have spares / when we order some spares.

The Vertex crane is smarter and safer now.  This upgrade ensures that the two sections of I-beam (8ft, 4ft) remain firmly latched to form a straight member till the latch is released.

In specific, it ensures that problems such as this one do not occur in the future.

The new safety features are:

When the I-beam sections are latched together, a pneumatic piston ensures that the latch is secure. 

If the latch is not engaged the trolley does not move outward beyond the end of the 8-foot section of the I beam.

If the trolley is out on the 4-foot section of the beam then we cannot disengage the latch.

How does it work?

The state of the Limit Switch 1 changes when the trolly goes past it.    The Limit Switch 2 gets pressed when the two sections are latched together.

The pneumatic piston raises or lowers the latch.  The Pneumatic Latch Switch operates a pneumatic valve controlling the state of the piston.

The new controller now has Pneumatic Latch Switch in addition to the usual Start, Stop, Up, Down, In and Out buttons. 

Each of the Up, Down, In and Out buttons have two operational states:  Half pressed (low speed) and Full pressed (High Speed).  Their functions remain the same as before.

The new Pneumatic Switch:

When this switch is 'Engaged' and the 4 ft section is swung in-line with the 8 ft section, the two sections get latched together.

To unlatch them we have to throw the switch into the 'Disengage' state.  This makes the piston push the latch open and a spring rotates the 4 ft section about its pivot.

Limit Switch 2 is not pressed (I-beams not aligned straight) ==> Limit Switch 1 will prevent the trolley from out going beyond the 8 ft section.

While Limit Switch 2 is pressed we cannot disengage the latch.

Note: 

   The pneumatic piston requires 80psi of pressure to operate.  However we have only 40psi in the lab and the piston seems to operate quite well at this pressure as well.  I believe a request has been made to get an 80psi line laid just for this application.

(Jenne, Rana)

Tonight we noticed that there were significant improvements to be had in the predicted DARM Wiener filtering FF performance by using weighting filters and more taps in the FIR filter.

The plots below tell the story:

The first one shows the improvement in the residual (black & blue) by applying a weighting filter. The weight filter tilts the spectrum up at HF and applies and all real pole BP from 10-20 Hz.

The second plot shows the improvement gotten by using 3000 instead of 2000 taps for the Wiener filter. With the larger number of taps we not only get the big improvement at LF, but also some beefy reduction in the higher frequency stack modes and the LOS roll mode.

I'm not sure why we haven't run across this before; the weighting filter was arrived at today by just iterating by hand on the placement of poles and zeros until the trace looked nice.

Jenne is going to run this new filter on the S5-month that we have been using for stationarity testing.

* Some notes:

** this Wiener stuff is faster, by far, on rossa than either megatron or rosalba or my laptop. More than a factor of 3.

*** there is a bug with Macports/Matlab - if you get fftw3 with Macports, it sets itself as the right version to use. This confuses matlab in some cases.

     if you get the error about libfftw3.dylib, whe trying fft in matlab after installing macports, then you can fix it by setting the Matlab lib/ path with the fftw libraries to be ahead of /opt/local/lib in the LD_LIBRARY_PATH in your .cshrc.

I added an MEDM screen for the DFD to the GREEN screen. It is displayed in the attached screen shot.

This screen is located in: /cvs/cds/rtcds/caltech/c1/medm/c1gfd/C1GFD_DFD.adl

Rossa is a rather beefy machine. It effectively has 8 Intel i7 Cores (2.67 Ghz each) and 12 Gigs of ram.  Megatron only has 8 Gigs of ram and just 8 Opterons (1 GHz each).  Rosalba has 4 Quad Core2  (2.4 GHz) with only 4 Gigs of ram. 

This is a plot showing the old filters and the new ones we added this morning.

The new ones have a Cheby for AC coupling below 10 Hz and then a 500 Hz LP after the mixer. The LP frequency has been increased so that we can use this signal in a feedback loop to the ETM with a ~100 Hz UGF.

Joe injected a 234.567 etc. Hz sine wave into the excitation channel in the DFD INPUT filter. The spectrum of the output of the LP filter with the new filter is shown below with the RMS calculated from 300Hz down to 1mHz - see first attachment. The RMS is equal to about 2.5Hz. (Incidentally, the RMS is very much higher (slightly less than 400Hz - see second attachment) if you calculate it from 7kHz down to 1mHz). 

I sat down in the control room to find that ETMX and PRM's watchdogs had been tripped.  I don't know how long they've been crazy, but there was a big something that showed up in the seismometers around 16:30UTC, or ~11:30 this morning.  I don't find any significant earthquakes on the USGS site for that time though, so it might be more local, i.e. work next door or trucks or whatever.

I take back the suggestion that it was that seismic event.  Clearly the PRM and the ETMX were kicked at different times, neither of which is the same as the seismic action. Mystery.  You can see they have been ringing down for a while though, which is neat. 

[Joe, Jenne]

We modified the activateDAQ.py script to handle the C1PEM.ini file (defining the PEM channels being recorded by the frame builder) in addition to all the optics channels.  Jenne will be modifying it further so as to rename more channels.

[Koji and Kevin]

I measured the shot noise of POY and fit the data to determine the RF transimpedance at 11 MHz and the dark current. The transimpedance is (3.860 +- 0.006) kΩ. I realize that there are not many data points past the dark current but I did not want to take any further data because the light bulb was getting pretty bright. If this is a problem, I can try to redo the measurement using a lens to try to focus more of the light from the bulb onto the photodiode.

I also measured the spectrum and recorded a time series of the RF signal with the light to the photodiode blocked. These measurements do not show any large oscillations like the ones found for POX.

The plots of the measurements are on the wiki at http://lhocds.ligo-wa.caltech.edu:8000/40m/Electronics/POY.

[Suresh, Joe]

We added the following two new DAQ channels into the c1:GCV model.  The daq:analog input channels are on card ADC0 and correspond to channels 3 and 4 on the card.

c1:GCV-EXT_REF_OUT_DAQ   Sampling rate=2kHz  acquiring a 1Hz sine wave from the SRS Function Generator DS345.  This is using the Rb 10MHz signal as an external frequency reference.

c1:GCV-PLL_OUT_DAQ    Sa.rate=2kHz acquiring the demodulated signal from the PLL servo.

This work is connected to the study of VCO PLL loop noise at frequencies below 0.1Hz.    We are trying to measure phase noise in the VCO PLL servo at low frequencies as this noise would result in arm length fluctuations in the green-locking scheme.

I wonder why POY11 has the dark noise level of 90nV/rtHz that is 5 times larger than that of POX (18nV/rtHz)
even though the Q are the same (~15) and the transimpedance is better (3.9k instead of 2k).

What cause this high noise level?
What is the expected dark noise level?

Joe and I were looking at the RCG VCO algorithm to determine if we could adapt it to run at a faster rate (you can currently change its frequency at 1Hz). I noticed that the algorithm that is used to calculated the values of sine and cosine at time T1  is a truncated Taylor series which uses the values of sine and cosine calculated at time T1 - Delta t . I was concerned that there would be an accumulating phase error so I tested the algorithm in MATLAB and compared it to a proper calculation of sine and cosine. It turns out that at a given 'requested' frequency there is a constantly accumulating phase error - which means that the 'actual' frequency of the RCG VCO is incorrect. So I have plotted the frequency error vs requested VCO frequency. It gets pretty bad!

 Here's the code I used:

dt = 1/16384;

diffList = [];
% set the frequencies
flist = 1:5:8192;
for f = flist;
   
    % get the 'accurate' values of sine and cosine
    tmax = 0.05;
    time1 = dt:dt:tmax;
    sineT = sin(2.0*pi*f*time1);
    cosineT = cos(2.0*pi*f*time1);
   
    % determine the phase change per cycle
    dphi = f*dt*2*pi;
    cosT1 = 1:numel(time1);
    sinT1 = 0*(1:numel(time1));
   
    % use the RCG VCO algorithm to determine the values of sine and cosine
    for ii = 1:numel(time1) - 1;                 
        cosNew = cosT1(ii)*(1 - 0.5*dphi^2) ...
                      - (dphi)*sinT1(ii);
        sinNew = sinT1(ii)*(1 - 0.5*dphi^2) ...
                      + (dphi)*cosT1(ii);
                 
       
        cosT1(ii+1) = [ cosNew];
        sinT1(ii+1) = [ sinNew];
       
    end
    % extract the phase from the VCO values of sine and cosine
    phaseT = unwrap(angle(cosineT + i* sineT));
    phaseT1 = unwrap(angle((cosT1 + i*sinT1)));
   
    % determine the phase error for 1 cycle
    diff = phaseT1 - phaseT;
    % determine the frequency error
    slope = (diff(2) - diff(1))/(dt);
   
    diffList = [diffList, slope];
    disp(f)
    pause(0.001)
end

% plot the results
close all
figure
orient landscape
loglog(flist, abs(diffList/(2.0*pi)))
xlabel('Requested VCO Frequency (Hz)')
ylabel('Frequency error (Hz)')
grid on

print('-dpdf', '/users/abrooks/VCO_error.pdf')


Updated the FILTER.adl file to have the yellow button moved up, and replaced the symbol in the upper right with a white A with black background.  I made a backup of the filter file called FILTER_BAK.adl.  These are located in /opt/rtcds/caltech/c1/core/advLigoRTS/src/epics/util.

I also modified the Makefile in /opt/rtcds/caltech/c1/core/advLigoRTS/ to make the startc1SYS scripts it makes take in an argument.  If you type in:

sudo startc1SYS 1

it automatically writes 1 to the BURT RESTORE channel so you don't have to open the GDS_TP screen and by hand put a 1 in the box before the model times out.

The scripts also points to the correct burtwb and burtrb files so it should stop complaining about not finding them when running the scripts, and actually puts a time stamped burt snapshot in the /tmp directory when the kill or start scripts are run.  The Makefile was also backed up to Makefile_bak.

So today, after an "rm" error while working with the autoburt.pl script and burt restores in general, I asked Dan Kozak how to actually look at the backup data.  He said there's no way to actually look at it at the moment.  You can reverse the rsync command or ask him to grab the data/file if you know what you want.  However, in the course of this, we realized there was no /cvs/cds data backup.

Turns out, the rsync command line in the script had a "-n" option.  This means do a dry run.  Everything *but* the actual final copying.

I have removed the -n from the script and started it on nodus, so we're backing up as of 5:22pm today.

I'm thinking we should have a better way of viewing the backup data, so I may ask Dan and Stewart about a better setup where we can login and actually look at the backed up files.

In addition, tomorrow I'm planning to add cron jobs which will put changes to files in the /chans and /scripts directories into the SVN on a daily basis, since the backup procedure doesn't really provide a history for those, just a 1 day back backup.

This measurement pertains to the BL2002 VCO PLL unit.

Our goal is to measure the frequency fluctuations introduced by the VCO. 

First the VCO calibration was checked.  It is -1.75 MHz per volt.  The calibration data is below:

Next we measured the Transfer function between points A and B  in the diagram below using the Stanford Research System's SR785.  This measurement was done with loop opened just after the 1.9MHz LPF and with the loop closed.

The TF[open] / TF [closed ] gave the total gain in the loop.  As shown below:

Green curve is the Transfer Function with the loop open and the red with that of the loop closed.

Gain Shown below is the quotient TF[open]/TF[closed]

 c) As can be seen from the graph above the loop gain is >>1 over 0.1 to 300Hz.  And hence the frequency noise of the VCO is just the product of the voltage noise and the VCO calibration factor over this range,

d) the noise power at the point B was measured and multiplied by the VCO calibration  factor to yield dF(rms)/rtHz:

The green line with dots are the data

The blue line is the rms frequency fluctuation.

This corresponds to a arm length fluctuation of about 20pm.

All start and kill scripts for the front end models have been moved into the FE directory under scripts:  /opt/rtcds/caltech/c1/scripts/FE/.  I modified the Makefile in /opt/rtcds/caltech/c1/core/advLigoRTS/ to update and place new scripts in that directory. 

This was done by using

sed -i 's[scripts/start$${system}[scripts/FE/start$${system}[g' Makefile

sed -i 's[scripts/kill$${system}[scripts/FE/kill$${system}[g' Makefile

<p>I removed the rsync backup from nodus' crontab temporarily so as to not have multiple backup jobs running.&nbsp; The job I started from yesterday was still running.&nbsp; Hopefully the backup will finish by Monday.</p>
<p>The line I removed was:</p>
<p>0 5 * * * /opt/rtcds/caltech/c1/scripts/backup/rsync.backup</p>
<table align="left" width="786" cellspacing="1" cellpadding="1" border="2">
    <tbody>
        <tr>
            <td><span style="font-size: larger;">MC damp</span></td>
            <td><span style="font-size: larger;">dataviewer</span></td>
            <td><span style="font-size: larger;">diaggui</span></td>
            <td><span style="font-size: larger;">AWG</span></td>
            <td><span style="font-size: larger;">c1lsc</span></td>
            <td><span style="font-size: larger;">c1ioo</span></td>
            <td><span style="font-size: larger;">c1sus</span></td>
            <td><span style="font-size: larger;">c1iscex</span></td>
            <td><span style="font-size: larger;">c1iscex</span></td>
            <td><span style="font-size: larger;">RFM</span></td>
            <td><span style="">The Dolphins</span></td>
            <td><span style="font-size: larger;">Sim.Plant</span></td>
            <td><span style="font-size: larger;">Frame builder</span></td>
            <td><span style="font-size: larger;">TDS</span></td>
            <td><span style="font-size: larger;">Cabling</span></td>
        </tr>
        <tr>
            <td bgcolor="blue"><span style="font-size: larger;">&nbsp;</span></td>
            <td bgcolor="green"><span style="font-size: larger;">&nbsp;</span></td>
            <td bgcolor="blue"><span style="font-size: larger;">&nbsp;</span></td>
            <td bgcolor="yellow"><span style="font-size: larger;">&nbsp;</span></td>
            <td bgcolor="orange"><span style="font-size: larger;">&nbsp;</span></td>
            <td bgcolor="yellow"><span style="font-size: larger;">&nbsp;</span></td>
            <td bgcolor="blue"><span style="font-size: larger;">&nbsp;</span></td>
            <td bgcolor="yellow"><span style="font-size: larger;">&nbsp;</span></td>
            <td bgcolor="yellow"><span style="font-size: larger;">&nbsp;</span></td>
            <td bgcolor="blue"><span style="font-size: larger;">&nbsp;</span></td>
            <td bgcolor="blue"><span style="font-size: larger;">&nbsp;</span></td>
            <td bgcolor="red"><span style="font-size: larger;">&nbsp;</span></td>
            <td bgcolor="blue"><span style="font-size: larger;">&nbsp;</span></td>
            <td bgcolor="orange"><span style="font-size: larger;">&nbsp;</span></td>
            <td bgcolor="orange"><span style="font-size: larger;">&nbsp;</span></td>
        </tr>
    </tbody>
</table>

Removed some lines from the PATH environment variable since they point to old codes which no longer work with the new frame builder and setup.

The change was:

#setenv PATH $LINUXPATH/bin:$GDSPATH/bin:$ROOTSYS/bin:$TDSPATH/bin:${SCRIPTPATH}:$PATH
setenv PATH $TDSPATH/bin:${SCRIPTPATH}:$PATH


We set up the mixer based FD to check out its noise performance.

It is being acquired as C1:GCV-XARM_FINE_OUT_DAQ.

We have calibrated it by driving the frequency of the RF signal generator and putting the value into the GAIN field. We got 100 kHz / 5450 counts; the _OUT_DAQ channel is now being recorded in units of Hz. The cable length has been adjusted so that the full mixer output can swing 16 MHz peak-peak before turning over.

Also, we did a lot of cable cleanup around the IO rack. Kiwamu and Suresh's setups were somewhat dismantled. The whole area was too messy and too hacky to be allowed to survive. Our "temporary" setups have a way of becoming permanent holding places for barrels, adapters, duct tape, etc.

I swapped over to a 3x longer cable (old 65 ft. Pasternak cable from ancient 40m days). The old one was 6m, the new one is 18.2 m. It was already coiled up so I put it into a tupperware box to shield it somewhat from the HVAC wind.

The noise went down nearly proportional to the length (after I recalibrated the DAQ channel for the ~3x higher phase->voltage gain). With this length, the peak-peak mixer range is 5.5 MHz, so still enough to go an FSR here.

I give credit to the low frequency improvement entirely to Tupperware for their excellent containers. The current noise limit is most likely the SR560.

The backup appears to have finished on nodus, and I've put the rsync job back in the crontab.

 Yesterday I moved the whole green electronics stuff, which had been sitting on the floor at the X end,  into a new electronics rack.

The rack now is placed under the cable rail close to the ETMX chamber.

[Joe, Rana]

Filter definitions for the decimation filters to epics readback channels (like _OUT16) can be found in the fm10Gen.c code (in /opt/rtcds/caltech/c1/core/advLigoRTS/src/include/drv).

At the moment, the code is broken for systems running at 32k, 64k as they look to be defaulting to the 16k filter.  I'd like to also figure out the notation and plot the actual filter used for the 16k.

Rana has suggested a 2nd order, 2db ripple low pass Cheby1 filter at 1 Hz.

  51 #if defined(SERVO16K) || defined(SERVOMIXED) || defined(SERVO32K) || defined(SERVO64K) || defined(SERVO128K) || defined(SERVO256K)
  52 static double sixteenKAvgCoeff[9] = {1.9084759e-12,
  53                                      -1.99708675982420, 0.99709029700517, 2.00000005830747, 1.00000000739582,
  54                                      -1.99878510620232, 0.99879373895648, 1.99999994169253, 0.99999999260419};
  55 #endif
  56
  57 #if defined(SERVO2K) || defined(SERVOMIXED) || defined(SERVO4K)
  58 static double twoKAvgCoeff[9] = {7.705446e-9,
  59                                  -1.97673337437048, 0.97695747524900,  2.00000006227141,  1.00000000659235,
  60                                  -1.98984125831661,  0.99039139954634,  1.99999993772859,  0.99999999340765};
  61 #endif
  62
  63 #ifdef SERVO16K
  64 #define avgCoeff sixteenKAvgCoeff
  65 #elif defined(SERVO32K) || defined(SERVO64K) || defined(SERVO128K) || defined(SERVO256K)
  66 #define avgCoeff sixteenKAvgCoeff
  67 #elif defined(SERVO2K)
  68 #define avgCoeff twoKAvgCoeff
  69 #elif defined(SERVO4K)
  70 #define avgCoeff twoKAvgCoeff
  71 #elif defined(SERVOMIXED)
  72 #define filterModule(a,b,c,d) filterModuleRate(a,b,c,d,16384)
  73 #elif defined(SERVO5HZ)
  74 #else
  75 #error need to define 2k or 16k or mixed
  76 #endif

I did a yum-install of the latest ldg-client (to get onto the LIGO Clusters) on Rossa. 

I followed the instructions on the wiki page, and everything seemed to work nicely.

I think the new ldg client installs somewhere on the local computer, so if anyone wants cluster access on any other computer, they should follow the same directions.

I blocked the  AP table's south west 10" ID port since it is obsolete with the new layout.

Reminder: items on the enclosure self can fall down in an earthquake. I moved oscilloscope and heavy calorimeter head from the edge of the cliff.

Updated the c1scx model to have two Lockin demodulators (C1:SUS-ETMX_LOCKIN1 and C1:SUS-ETMX_LOCKIN2).  There is a matrix C1:SUS-ETMX_INMUX which directs signals to the inputs of LOCKIN1 and LOCKIN2.  Currently only the GREEN_TRX signal is the only signal going in to this matrix, the other 3 are grounds.  The actual clocks themselves had to be at the top level (they don't work inside blocks) and thus named C1:SCX-ETMX_LOCKIN1_OSC and C1:SCX-ETMX_LOCKIN2_OSC.

There is a signal (IPC name is C1:GCV-SCX_GREEN_TRX) going from the c1gcv model to the c1scx model, which will contain the output from Jenne's green transmission PD which will eventually be placed. I've placed a filter bank on it in the c1gcv model as a monitor point, and it corresponds to C1:GCV-GREEN_TRX.

The suspension control screens were modified to have a screen for the Matrix feeding signals into the two lockin demodulators.  The green medm screen was also modified to have readbacks for the GREEN_TRX and GREEN_TRY channels.

So on the board, the top channel (labeled 1, corresponds to code ADC_0_0) is MCL.

Channel 2 (ADC_0_1) is assigned to frequency divided green signal.

Channel 3 (ADC_0_2) is assigned to the beat PD's DC output.

Channel 4 (ADC_0_3) is assigned to the green power transmission for the x-arm.

Channel 5 (ADC_0_4) is assigned to the green power transmission for the y-arm.

Using a stray beam that is generated as the transmitted green beam from the Xarm goes through the viewport to the PSL table, I installed a fast lens (because I was constrained for space) and a Thorlabs PDA36 photodiode on the PSL table.

The BNC cable runs along the edge of the PSL table, up the corner hole with the huge bundle of cables, and over to IOO_ADC_0. It's channel 3 on the simulink model, which means that it is plugged into connector #4.

With the green resonating TEM00, I have ~1.4V output from the photodiode, as seen on a voltmeter. This corresponds to ~1500 counts on the MEDM screen.

Note to self:  Switch to a ~1cm diode with a boatload of gain (either from the 40m or Bridge), and use transmission through a steering mirror of the actual beat note path, not the jittery viewport pickoff.  Want RIN noise level to be about 1e-5, only care about below ~100Hz so don't need broadband.

 I repeated the same measurement as that Koji did before (see here) with the mixer-based frequency discriminator.

The frequency fluctuation of the beat note is now 50 kHz in rms integrated down to 0.1 Hz, which is a bit better than before.

However there still is the same undesired structure in the spectrum below 10 Hz.

Fig.1 power spectra of the green beat note fluctuation in terms of frequency fluctuation.

   Red curves were taken when the IR was locked to the MC, and the green was locked to the X arm.

Blue curves were taken when both the IR and the green were locked to the X arm.

Black curve was also the one taken when the IR and the green were locked to the X arm, but showing the lower noise level.

I have no idea what exactly was going on when I took the black curve, but this noise level sometimes showed up.

The discrepancy may come from a kind of calibration error although I kept using the same calibration factor to convert the data from count to frequency.

Need more investigations.

 Additionally Koji and I took the coherence between the beat fluctuation and the transmitted lights of both the IR and the green.

It showed a strong coherence at 1 Hz, which is one of the dominant noise of the beat note.

This probably indicates that the 1 Hz peak is produced by a coupling from amplitude fluctuation.

 For monitoring the green transmitted light, I used the Jenne's PD (see here)

The air condition was off for the south arm. I  turned it on.

[Joe,Alex]

Alex came over and we installed the new Dolphin drivers so that the front ends using the Dolphin PCIe RFM network don't pause for a long time when one of the other nodes in the network go down.  Generally this pause would cause the code to time out and quit.  Now you can take c1lsc or c1sus down without having the other have problems.

We did note on reboot however, that the Dolphin_wait script sometimes (not always) seems to hang.  Since this is run at boot up, to ensure the dolphin card has had enough to allocate memory space for data to be written/read from by the IOP process, it means nothing else in the startup script gets run if it does happen.  In this case, running "pkill dolphin_wait" may be necessary.

Note that you may still have problems if you hit the power button to force a shutdown (i.e. holding it for 4 seconds for immediate power off), but as long as you do a "reboot" or "shutdown -r now" type command, it should come down gracefully. 

What was done:

Alex grabbed the code from his server, and put it /home/controls/DIS/ on fb.

He ran the following commands in that directory to build the code.

./configure  '--with-adapter=DX' '--prefix=/opt/DIS'

make

sudo make install

He proceeded to modify the /diskless/root/etc/rc.local to have the line:

insmod /lib/modules/2.6.34.1/kernel/drivers/dis/dis_kosf.ko

In that same file he commented out

cd /root

and

exec /bin/bash/

He then modified the run levels in /diskless/root/etc/inittab. Level 0, level 3, and level 6 were changed:

l0:0:wait/etc/rc.halt

l3:3:wait:etc/rc.level3

l6:6:wait:/etc/rc.reboot

Then he created the scripts he was refering to:

rc.level3 is just:

exec /bin/bash

rc.halt is:

/opt/DIS/sbin/dxtool prepare-shutdown 0
sleep 3
halt -p

rc.reboot is:

reboot

Basically rc.halt calls a special code which prepares the Dolphin RFM card to shutdown nicely.  This is why just hitting the power button for 4 seconds will cause problems for the rest of the dolphin network.

We then checked out of svn the latest dolphin.c in  /opt/rtcds/caltech/c1/core/advLigoRTS/src/fe

The Dolphin RFM cards have a new numbering scheme.  4 is reserved for special  broadcasts to everyone, so the Dolphin node IDs now start at 8.  So we needed to change the c1lsc and c1sus Dolphin node IDs.

To change them we went to /etc/dis/dishosts.conf on the fb machine, and changed the following lines:

HOSTNAME: c1sus
ADAPTER:  c1sus_a0 4 0 4
HOSTNAME: c1lsc
ADAPTER:  c1lsc_a0 8 0 4

to

HOSTNAME: c1sus
ADAPTER:  c1sus_a0 8 0 4
HOSTNAME: c1lsc
ADAPTER:  c1lsc_a0 12 0 4

The FE models for the c1lsc and c1sus machines were recompiled and then the computers were rebooted.  After having them come back up, we tested that there was no time out by shutting down c1lsc and watching c1sus. We then reveresed and shutdown c1sus while watching c1lsc.  No problems occured.  Currently they are up and communicating fine.

This is with reference to Kevin and Jenne's elogs  # 3890, 4034 and 4048 . 

While the electronics are working okay, there is no DC signal from the photodiode. 

Since the solderings and tracks on the PCB were fine I took a close look at the exposed front face of the photodiode.

As we can see, one of the thin wires on the top surface of the photodiode is broken.  We can see some wipe marks closer to the lower left edge..

Something seems to have brushed across the exposed face of the photodiode and dislodged the wire.

Question:

The new photodiode still has its protective can intact.   Do we need to remove the can and expose the photodiode before istallation?

I set up video monitoring of MC1 and MC3

A new photodiode ( Perkin and Elmer Model no. C30642GH Sl No.1526) has been installed in the place of the old photodiode.  The datasheet of this model is attached. 

The 68pF capacitor which was present in parallel with the photodiode has been removed.  Here is a picture of the PCB ( in all its gory detail!) and the photodiode after replacement.

I also checked to see if we have a DC output from the new PD.  With 375mW of 1064nm light incident we have 15mV of output.  Which matches well with the typical Reponsivity of 0.8V/A reported in the datasheet and our REFL11 ckt .  The schematic of the ckt is also attached here for easy reference.  The various factors are

V_dc = 0.375 mW x 0.8 V/A x 10 Ohm x 5 = 15mV

The last factor is the gain of the last stage on the DC route.

When I reassembled the box I noticed that there is problem with the SMA connectors popping out of the box.  The holes seem misplaced so I enlarged the holes to remove this concern.

375 mW is way too much light. We must never put more than 100 mW on any of these diodes. We don't want to blow up more diodes like we did with the WFS. The InGaAs diodes often show an excess dark noise before they finally let go and completely fail. This one may show excess during the shot noise testing.

We should ensure that the beam paths are engineered so that none of these new detectors ever sees such high light levels.

The DC path should be made to let us see a 10V from the differential EPICS readout when there is 100 mA of photocurrent (i.e. an effective 100 Ohms transimpedance):

0.1 A  * 10 V/A * 5 V/V * 2V/V

The last factor of 2 is from the single to differential conversion.

If we really only get 15 mV from 375 mW, then this diode or the circuit is broken.

Suresh is saying 375mW and 0.375mW. Let's wait for his update of the actual power.

Also he is not using EPICS, there may be the factor of two missing for now.

The amounts of the X arm's beam off-centering have been measured by the A2L technique.

So now we are able to start aligning the IR beam axis in a quantitative way.

(motivation)

 Since we saw big residual motions at 1 Hz, 16 Hz on both the green beat note signal and the IR PDH signal (see #4268 and #4211),

we are suspecting that these noise come from an angle to length coupling.

In order to minimize the angle to length coupling, one thing we can do is to bring the beam spots to the center of ITMX and ETMX more precisely.

To do it, we have to quantitatively know how well the beam spots are on the center of the optics. Therefore I started measuring the amount of the beam off-centering.

(method)

 The A2L technique was used to measure the off-centering with the real-time lockin system, which has been recently embedded in the real-time code by Joe (see #4265).

The idea is the same as Yuta did before (see #3863).

But this time the excitation signal from the real-time oscillator was injected directly to the coil matrix on either ITMX or ETMX, at 18.13 Hz with the amplitude of about 400 cnt.

When the IR laser stays locked to the X arm, the LSC feedback signal is demodulated with the oscillator signal.

This demodulated signal gives the amount of the off-centering.

For this purpose I modified Yuta's A2L script such that we can use it also for the X arm.

(results)

 I obtained the following values:

     - ETMX

         PIT  = -1.61 mm

         YAW =  -0.918 mm

    - ITMX

         PIT = -3.76 mm

        YAW = -2.24 mm

I used the same calibration factor as that of Koji calculated (see #3020) for MC, in order to convert the results from the coil gain to the off-centering.

These values are consistent with the spots appearing on the CCD monitors.