40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
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ID Date Author Type Category Subject
  13326   Thu Sep 21 01:55:16 2017 ranaUpdateALSX End table of Shame

Image #1: No - we do not use magnetic mounts for beam dumps. Use a real clamp. It has to be rigid. "its not going anywhere" is a nonsense statement; this is about vibration amplitude of nanometers.

Image #2: No - we do not use sticky tape to put black glass beam dumps in place ever, anywhere. Rigid dumps only.

Image #3: Please do not ruin our nice black glass with double sticky tape. We want to keep the surfaces clean. This one and a few of the other Mickey Mouse black glass dumps on this table were dirty with fingerprints and so very useless.

Image #4: This one was worst of all: a piece of black glass was sticky taped to the wall. Shameful.

Please do not do any work on this table without elogging. Please never again do any of these type of beam dumping - they are all illegal. Better to not dump beams than to do this kind of thing.

All dumps have to be rigidly mounted. There is no finger contacting black glass or razor dumps - if you do, you might as well throw it in the garbage.

Attachment 1: 20170921_003143.jpg
20170921_003143.jpg
Attachment 2: 20170921_002430.jpg
20170921_002430.jpg
Attachment 3: 20170921_002243.jpg
20170921_002243.jpg
Attachment 4: 20170921_001906.jpg
20170921_001906.jpg
  13325   Thu Sep 21 01:32:00 2017 gautamUpdateALSAUX X Innolight AM measurement running

[rana,gautam]

We set up a measurement of the AUX X laser AM today. Some notes:

  • PDA 55 that was installed as a power monitor for the AUX X laser has been moved into the main green beam path - it is just upstream of the green shutter for this measurement.
  • AUX X laser power into the doubling crystal was adjusted by rotating HWP upstream of IR Faraday (original angle was 100, now it is 120), until the DC level of the PDA 55 output was ~2.5V on a scope (high impedance).
  • BNC-T was installed at the PZT input of the Innolight - one arm of the T is terminated to ground via 50 ohms. The purpose of this is to always have the output of the power splitter from the network analyzer RF source drive a 50 ohm load.
  • The output of the Green PDH servo to the Innolight PZT was disconnected downstream of the summing Pomona box - it is now connected to one output of a power splitter (borrowed from SR function generator used to drive the PZT) connected to the RF source output of the AG4395.
  • Other output of power splitter connected to input R of AG4395.
  • PDA55 output has been disconnected from CH5 of the AA board. It is connected to input A of the AG4395 via DC block.

Attachment #1 shows a preliminary scan from tonight - we looked at the region 10kHz-10MHz, with an IF bandwidth of 100Hz, 16 averages, and 801 log-spaced frequencies. The idea was to get an idea of where some promising notches in the AM lie, and do more fine-bandwidth scans around those points. Data + code used to generate this plot in Attachment #2.

Rana points out that some of the AM could also be coming from beam jitter - so to put this hypothesis to test, we will put a lens to focus the spot more tightly onto the PD, repeat the measurement, and see if we get different results.

There were a whole bunch of little illegal things Rana spotted on the EX table which he will make a separate post about.

I am running 40 more scans with the same params for some statistics - should be done by the morning.

Quote:

I borrowed the HP impedance test kit from Rich Abbott today. The purpose is to profile the impedance of the NPRO PZTs, as part of the AUX PDH servo investigations. It is presently at the X-end. I will do the test in the coming days.
 


Update 12:00 21 Sep: Attachment #3 shows schematically the arrangement we use for the AM measurement. A similar sketch for the proposed PM measurement strategy to follow. After lunch, Steve and I will lay out a longish BNC cable from the LSC rack to the IOO rack, from where there is already a long cable running to the X end. This is to facilitate the PM measurement.

Update 18:30 21 Sep: Attachment #4 was generated using Craig's nice plotting utility. The TF magnitude plot was converted to RIN/V by dividing by the DC voltage of the PDA 55 of ~2.3V (assumption is that there isn't significant difference between the DC gain and RF transimpedance gain of the PDA 55 in the measurement band) The right-hand columns are generated by calculating the deviation of individual measurements from the mean value. We're working on improving this utility and aesthetics - specifically use these statistics to compute coherence, this is a work in progress. Git repo details to follow.

There are only 23 measurements (I was aiming for 40) because of some network connectivity issue due to which the script stalled - this is also something to look into. But this sample already suggests that these measurement parameters give consistent results on repeated measurements above 100kHz.

TO CHECK: PDA 55 is in 0dB gain setting, at which it has a BW of 10MHz (claimed in datasheet).


Some math about relation between coherence \gamma_{xy}(f) and standard deviation of transfer function measurements:

\mathrm{SNR}(f) = \sqrt{\frac{\gamma_{xy}^{2}(f)}{1-\gamma_{xy}^{2}(f)}}

\sigma_{xy}^{2} = \frac{1-\gamma_{xy}^{2}(f)}{2N\gamma_{xy}^{2}(f)}|H(f)|^2  --- relation to variance in TF magnitude. We estimate the variance using the usual variance estimator, and can then back out the coherence using this relation.

\sigma_{\theta_{xy}} = \mathrm{tan}^{-1}\left [ \sqrt{\frac{1-\gamma_{xy}^{2}(f)}{2N\gamma_{xy}^{2}(f)}} \right ] --- relation to variance in TF phase. Should give a coherence profile that is consistent with that obtained using the preceeding equation.

It remains to code all of this up into Craig's plotting utility.

Attachment 1: Innolight_AM.pdf
Innolight_AM.pdf
Attachment 2: Innolight_AM.tar.gz
Attachment 3: IMG_7599.JPG
IMG_7599.JPG
Attachment 4: 20170921_203741_TFAG4395A_21-09-2017_115547_FourSquare.pdf
20170921_203741_TFAG4395A_21-09-2017_115547_FourSquare.pdf
  13324   Wed Sep 20 16:14:17 2017 gautamUpdateEquipment loanImpedance test kit borrowed from Downs

I borrowed the HP impedance test kit from Rich Abbott today. The purpose is to profile the impedance of the NPRO PZTs, as part of the AUX PDH servo investigations. It is presently at the X-end. I will do the test in the coming days.
 

  13323   Wed Sep 20 15:49:26 2017 ranaOmnistructureComputersnew internet

Larry Wallace hooked up a new switch (Brocade FWS 648G) today which is our 40m lab interface to the outside world internet. Its faster.

He then, just now, switched over the cables which were going to the old one into the new one, including NODUS and the NAT Router. CDS machines can still connect to the outside world.

In the next week or two, he'll install a new NAT for us so that we can have high speed comm from CDS to the world.

  13322   Tue Sep 19 14:00:41 2017 SteveUpdatePEMearthquakes

No sus tripped. Seimometers do not see the 5.3M  ?

Quote:

Southern Mexio is still shaking..... so as we

 

Attachment 1: 7.1MX5.3J.png
7.1MX5.3J.png
  13321   Tue Sep 19 11:05:26 2017 SteveUpdateVACRGA scan at day 334

 

 

Attachment 1: RGAscan334d.png
RGAscan334d.png
  13320   Mon Sep 18 18:40:34 2017 gautamUpdateCDSFB wiper script

I did a further check on the wiper script by changing the "percent_keep" from 85.0 to 75.0, and running the script in "dry_run" mode again. The script then output to console the names of all the files it would delete in order to free up the required amount of space (but didn't actually delete any files as it was a dry run). Seemed to be sensible.

To set up the cron job, I did the following on FB1:

  • crontab -e opened up the crontab
  • Copied over a script called "wiper.cron" from /opt/rtcds/caltech/c1/target/fb to /opt/rtcds/caltech/c1/target/daqd. This essentially contains a bunch of instructions to run the wiper script with the --delete flag, and write the console output to a log file.
  • Added the following line: 33 3 * * * /opt/rtcds/caltech/c1/target/daqd/wiper.cron. So the cron job should be executed at 3:33AM everyday.
  • The cron daemon seems to be running - sudo systemctl status cron.service yields the following output:
    controls@fb1:~ 0$ sudo systemctl status cron.service
    ● cron.service - Regular background program processing daemon
       Loaded: loaded (/lib/systemd/system/cron.service; enabled)
       Active: active (running) since Mon 2017-09-18 18:16:58 PDT; 27min ago
         Docs: man:cron(8)
     Main PID: 30183 (cron)
       CGroup: /system.slice/cron.service
               └─30183 /usr/sbin/cron -f
    Sep 18 18:16:58 fb1 cron[30183]: (CRON) INFO (Skipping @reboot jobs -- not system startup)
    Sep 18 18:17:01 fb1 CRON[30205]: pam_unix(cron:session): session opened for user root by (uid=0)
    Sep 18 18:17:01 fb1 CRON[30206]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
    Sep 18 18:17:01 fb1 CRON[30205]: pam_unix(cron:session): session closed for user root
    Sep 18 18:25:01 fb1 CRON[30820]: pam_unix(cron:session): session opened for user root by (uid=0)
    Sep 18 18:25:01 fb1 CRON[30821]: (root) CMD (command -v debian-sa1 > /dev/null && debian-sa1 1 1)
    Sep 18 18:25:01 fb1 CRON[30820]: pam_unix(cron:session): session closed for user root
    Sep 18 18:35:01 fb1 CRON[31515]: pam_unix(cron:session): session opened for user root by (uid=0)
    Sep 18 18:35:01 fb1 CRON[31516]: (root) CMD (command -v debian-sa1 > /dev/null && debian-sa1 1 1)
    Sep 18 18:35:01 fb1 CRON[31515]: pam_unix(cron:session): session closed for user root

     

  • crontab -l on FB1 now shows the following:
    controls@fb1:~ 0$ crontab -l
    # Edit this file to introduce tasks to be run by cron.
    #
    # Each task to run has to be defined through a single line
    # indicating with different fields when the task will be run
    # and what command to run for the task
    #
    # To define the time you can provide concrete values for
    # minute (m), hour (h), day of month (dom), month (mon),
    # and day of week (dow) or use '*' in these fields (for 'any').#
    # Notice that tasks will be started based on the cron's system
    # daemon's notion of time and timezones.
    #
    # Output of the crontab jobs (including errors) is sent through
    # email to the user the crontab file belongs to (unless redirected).
    #
    # For example, you can run a backup of all your user accounts
    # at 5 a.m every week with:
    # 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
    #
    # For more information see the manual pages of crontab(5) and cron(8)
    #
    # m h  dom mon dow   command
    33 3 * * * /opt/rtcds/caltech/c1/target/daqd/wiper.cron

Let's see if this works.

Quote:

Since the script seems to be working now, I am going to set it up on FB1's crontab. Thanks Chris!.

 

  13319   Mon Sep 18 17:51:26 2017 gautamUpdateCDSFB wiper script

It is a little different - specifically, the way the splitting of the output of the "du" command into disk usage and directory is different (see Attachment #1). Apart from this, some of the parameters (e.g. what percentage to keep free) are different.

I changed the percentages to match what we had here, and edited a couple of other lines to print out the files that will be deleted. The dry run seemed to work okay, it produced the output below. Not sure why "df -h" reports a different use percentage though...

Since the script seems to be working now, I am going to set it up on FB1's crontab. Thanks Chris!.

controls@fb1:/opt/rtcds/caltech/c1/target/daqd 0$ ./wiper.pl
Mon Sep 18 17:47:06 PDT 2017
Dry run, will not remove any files!!!
You need to rerun this with --delete argument to really delete frame files
Directory disk usage:
/frames/trend/minute_raw 47126124k
/frames/trend/minute 22900668k
/frames/trend/second 760359168k
/frames/full 19337278516k
Combined 20167664476k or 19694984m or 19233Gb
/frames size 25097525144k at 80.36%
/frames is below keep value of 85.00%
Will not delete any files
df reported usage 80.36%
controls@fb1:/opt/rtcds/caltech/c1/target/daqd 0$ df -h
Filesystem                        Size  Used Avail Use% Mounted on
/dev/sda4                         2.0T  1.7T  152G  92% /
udev                               10M     0   10M   0% /dev
tmpfs                              13G  177M   13G   2% /run
tmpfs                              32G     0   32G   0% /dev/shm
tmpfs                             5.0M     0  5.0M   0% /run/lock
tmpfs                              32G     0   32G   0% /sys/fs/cgroup
/dev/sda2                          19G  3.7G   14G  21% /var
/dev/sda1                         461M   65M  373M  15% /boot
/dev/sdb1                          24T   19T  3.5T  85% /frames
192.168.113.104:/home/cds/rtcds   2.0T  1.6T  291G  85% /opt/rtcds
192.168.113.104:/home/cds/rtapps  2.0T  1.6T  291G  85% /opt/rtapps
tmpfs                             6.3G     0  6.3G   0% /run/user/1001
Quote:

Attached is the version of the wiper script we use on the CryoLab cymac. It works with perl v5.20.2. Is this different from what you have?

 

Attachment 1: perlDiff.png
perlDiff.png
  13318   Mon Sep 18 17:30:54 2017 ChrisUpdateCDSFB wiper script

Attached is the version of the wiper script we use on the CryoLab cymac. It works with perl v5.20.2. Is this different from what you have?

Attachment 1: wiper.pl
#!/usr/bin/perl
use File::Basename;

print "\n" .  `date` . "\n";
# Dry run, do not delete anything
$dry_run = 1;

if ($ARGV[0] eq "--delete") { $dry_run = 0; }

print "Dry run, will not remove any files!!!\n" if $dry_run;
... 184 more lines ...
  13317   Mon Sep 18 17:17:49 2017 gautamUpdateCDSFB wiper script

After trying to debug this issue using the Perl debugger, I concluded that the problem is in the part of the code that splits the output of the "du" command into directory and disk usage. For whatever, reason, this isn't working. The version of perl running on the new FB1 machine is 5.20.2, whereas I suspect the version running on the old FB machine was 5.14.2 (which is the version on all the Ubuntu 12 workstations and megatron). Unclear whether downgrading the Perl version is the right way to go.

The FB1 disk is now getting close to full, the usage is up to 85% today.

Quote:

Before I go down a Perl rabbit hole, has anyone seen such an error or is aware of some reason why this might not work on the new FB? Am I even using the correct scripts?

 

  13316   Mon Sep 18 15:00:15 2017 rana, gautamFrogsComputer Scripts / Programsgateway PWD change

We implemented the post-SURF-season nodus password change today.

New password can be found at the usual location.

  13315   Sat Sep 16 10:56:19 2017 ranaUpdateLSCCoil de-whitening switching investigation

The absence of evidence is not evidence of absence.

  13314   Fri Sep 15 17:08:58 2017 gautamUpdateLSCCoil de-whitening switching investigation

I downloaded a segment of data from the time when the DRMI was locked with the BS and ITM coil driver de-whitening switched on, and looked at coherence between MC transmission and the MICH error signal. Attachment #1 doesn't show any broadband high coherence between 60-300Hz, so it cannot explain the noise in the full range between 60-300Hz. 

The DQ channel for the MC transmission is recorded at 1024 kHz, so to calculate the coherence, I had to decimate the 16K MICH data. 

Since we have the AOM installed, I suppose we can actually measure the intensity noise coupling to MICH by driving a line in the AOM. 

I also checked for coherence in the 60-300Hz band between MICH/PRCL and MICH/SRCL, and didn't see any appreciable coherence. Need to think about this more.

Quote:

 Rana suggested checking coherence with MC transmission to see if this could be laser intensity noise.

Attachment 1: DRMI_IntensityNoise.pdf
DRMI_IntensityNoise.pdf
  13313   Fri Sep 15 16:00:33 2017 gautamUpdateLSCSensing measurement

I've been working on analyzing the data from the DRMI locks last week.

Here are the results of the sensing measurement.

Details:

  1. The sensing measurement is done by using the existing sensing matrix infrastructure to drive the actuators for the various DoFs at specific frequencies (notches at these frequencies are turned on in the control loops during the measurement).
  2. All the analysis is done offline - I just note down the times at which the sensing lines are turned on and then download the data later. The amplitudes of the oscillators are chosen by looking at the LSC PD error signal spectra "live" in DTT, and by increasing the amplitude until the peak height is ~10x above the nominal level around that frequency. This analysis was done on ~600seconds of data.
  3. The actual sensing elements in the various PDs are calculated as follows:
    • Calculate the Fourier coefficients at the excitation frequency using the definition of the complex DFT in both the LSC PD signal and the actuator signal (both are in counts). Windowing is "Tukey", and FFT length used is 1 second.
    • Take their ratio
    • Convert to suitable units (in this case V/m) knowing (i) The actuator discriminant in cts/m and (ii) the cts/V ADC calibration factor. Any whitening gain on the PD is taken into account as well.
    • If required, we can convert this to W/m as well, knowing (i) the PD responsivity and (ii) the demodulation chain gain.
    • Most of this stuff has been scripted by EricQ and is maintained in the pynoisesub git repo.

The plotting utility is a work in progress - I've basically adapted EricQs scripts and added a few features like plotting the uncertainties in magnitude and phase of the calculated sensing elements. Possible further stuff to implement:

  • Only plot those elements which have good coherence in the measurement data. At present, the scripts check the coherence and prompt the user if there is poor coherence in a particular channel, but no vetos are done.
  • The uncertainty calculation is done rather naively now - it is just the standard deviation in the fourier coefficient determined from various bins. I am told that Bendat and Piersol has the required math. It would be good to also incorporate the uncertainties in the actuator calibration. These are calculated using the python uncertainties package for now.
  • Print a summary of the parameters used in the calculation, as well as sensing elements + uncertainty in cts/m, V/m and W/m, on a separate page.
  • Some aesthetics can be improved - I've had some trouble getting the tick intervals to cooperate so I left it as is for the moment.

Also, the value I've used for the BS actuator calibration is not a measured one - rather, I estimated what it will be by scaling the old value by the same ratio which the ITMs have changed by post de-whitening board mods. The ITM actuator coefficients were recently  measured here. I will re-do the BS calibrations over the weekend.

Noise budgeting to follow - it looks like I didn't set the AS55 demod phase to the previously determined optimal value of -82degrees, I had left it at -42 degrees. To be fixed for the next round of locking.

Attachment 1: DRMI1f_Sep5.pdf
DRMI1f_Sep5.pdf
  13312   Fri Sep 15 15:54:28 2017 gautamUpdateCDSFB wiper script

A wiper script is not yet set up for our new Frame-Builder. The disk usage is ~80% now, so I think we should start running a wiper script that manages overall disk usage and deletes old frame files to this end.

From what I could find on the elog, the way this was done was by running a cron job on FB. There is a perl script, /opt/rtcds/caltech/c1/target/fb/wiper.pl, which from what I could understand, runs a bunch of du commands on different directories to determine if there is a need to delete any files.

I copied this script over to /opt/rtcds/caltech/c1/target/daqd/wiper.pl. This is the directory in which all the new FB stuff resides. Conveniently, the script has a "dry-run" option, which I tried running on FB1. However, I get the following error message:

Fri Sep 15 15:44:45 PDT 2017
Dry run, will not remove any files!!!
You need to rerun this with --delete argument to really delete frame files
Directory disk usage:
 /frames/trend/minute_rawk
Combined 0k or 0m or 0Gb
Illegal division by zero at ./wiper.pl line 98.


So it would seem that for some reason, the du commands aren't working. From what I could tell, there aren't any directory paths specific to the old FB machine that need to be changed. I believe the script was working prior to the FB disk crash - unfortunately it doesn't look like this script was under version control but I don't think any changes have been made to this script.

Before I go down a Perl rabbit hole, has anyone seen such an error or is aware of some reason why this might not work on the new FB? Am I even using the correct scripts?

  13311   Tue Sep 12 11:44:16 2017 KiraUpdatePEMtemp sensor update

Got it to work. A cable was broken and the AD586 also broke at the same time so it took a while to find the problem. I had to create a makeshift cable out of three parts so once I replace it for an actual cable, it will be good to go for a test.

Quote:

Today, I stuck on the sensors to a metal block using a flag, rubber bands, and some thermal paste (1st attachment). I then wrapped the whole thing in about 4 layers of insulation and a lot of tape (2nd attachment). The only things leading out of the box were the three connections to the sensors and a thermometer. I then connected the wires to their respective places on the board of the sensor. To get the readings out we would need to use an ADC. Gautam and I checked to make sure the ADC we have inside the lab goes from -10V to 10V so that it would be able to measure the 3V value the sensor typically measures. We then tried to connect all three sensors to a DC source simultaneously, but unfortunately one of them seems to have disconnected somewhere during the process, as it only showed 1.2V instead of 3V. I plan to fix this tomorrow morning so that we can hopefully set this up soon.

Quote:

I took off the AD590 and attached it to two long wires leading out from the board. This will allow us to attach the sensor to a metal block and not have to stick the whole board to it. I have also completed three identical copies of this and it's pretty much ready to be tested. According to Craig and Andrew's elog here, the sensor is very noisy and they added in a low pass filter to fix that, so that's something to consider for the final version of the circuit. I'll test what I have so far and see how that goes. We still need to figure out how to get readings from the sensors.

To attach the sensor to the metal block, I'll use some thermal paste and fasteners. I'll also put a thermometer on the block to record the actual temperature. I'll then wrap it in some insulation we have in the lab and have only some wires leading out of it to make measurements. I'll leave this setup overnight and record the outputs for about a full day. The fluctuations between the sensors will then indicate the noise of each individual sensor.

 

 

  13310   Mon Sep 11 23:31:50 2017 johannesUpdateCameraspost-vent camera capture comparison

The latest pre-unintended vent captures of the test mass face cameras were taken on June 2nd, 2017. Only exposures for ITMYF, ETMYF, and ETMXF exist in /users/sensoray/SensorayCaptures/. I took new captures for those three after locking the arms and having the dither-alignment on for 5+ minutes (exposures were taken after turning the dithering off). The capture script is choking on ITMXF, saying the channel can't lock on. Maybe that's why there's also no reference image for it. Capturing QUAD3, which shows ITMXF in the lower right corner, works, but we don't have a capture for reference. I also recorded dark fields after closing the PSL shutter. Naturally, these don't subtract out as well for the three-month old pictures, but it's actually not terrible and qualitatively one can still compare the subtracted images

Visually, ITMYF and ETMYF do not show a dramatic difference between then and now. ETMXF however, does. To get a numerical estimate for the difference in counts, I worked with the subtracted images and placed an aperture about 1.5x the size of the visible beam blob. I summed up the pixel values inside and subtracted the sum of the pixel values of an equally sized area from the upper left corner of the respective image, which looks free of subtraction artifacts and looks qualitatively similar to the background in the central region.

The pixel sum has gone up by about 50% between the exposures. I still have to do the same for the YARM optics but don't expect such a large discrepancy. Unfortunately we're missing those ITMYF expsures...

All pictures are organized in this format:

Pre-vent exposure Post-vent exposure
Pre-vent subtracted Post-vent subtracted

 

ITMYF

   

   

ETMYF

   

   

ETMXF

   

   

Attachment 11: ETMXF_pre_sub.bmp
  13309   Mon Sep 11 16:46:09 2017 SteveUpdatePEMearthquakes
Quote:

I was trying to get a lossmap measurement over the weekend but had some trouble first with the IMC and then with the PMC.

For the IMC: It was a bit too misaligned to catch and maintain lock, but I had a hard time improving the alignment by hand. Fortunately, turning on the WFS quickly once it was locked restored the transmission to nominal levels and made it maintain the lock for longer, but only for several minutes, not enough for a lossmap scan (can take up to an hour). Using the WFS information I manually realigned the IMC, which made locking easier but wouldn't help with staying locked.

For the PMC: The PZT feedback signal had railed and the PMC had been unlocked for 8+ hours. The PMC medm screen controls were generally responsive (I could see the modes on the CCDs changing) but I just couldn't get it locked. c1psl was responding to ping but refusing telnet so I keyed the crate, followed by a burt restore and finally it worked.

After the PMC came back the IMC has already maintained lock for more than an hour, so I'm now running the first lossmap measurements.

Southern Mexio is still shaking..... so as we

Attachment 1: M5.4eq.png
M5.4eq.png
  13308   Mon Sep 11 15:58:02 2017 SteveUpdateGeneralNPRO for repair

This NPRO has a tripping power output******

 

" Hi Eric,

I checked with the Engineer as Vincent is travelling.

“The lasers have serial number below 2000 which we cannot repair them, we only can repair NPRO laser has serial number 2000 or later.”

Thanks,

Betty-Ann Watt

Customer Service Professional
Global Customer Service/Communication & Commercial Optical Products "

www.lumentum.com

 

 

Attachment 1: NPRO_tripping.jpg
NPRO_tripping.jpg
  13307   Mon Sep 11 12:56:40 2017 johannesUpdateComputer Scripts / Programslossmap attempts

I was trying to get a lossmap measurement over the weekend but had some trouble first with the IMC and then with the PMC.

For the IMC: It was a bit too misaligned to catch and maintain lock, but I had a hard time improving the alignment by hand. Fortunately, turning on the WFS quickly once it was locked restored the transmission to nominal levels and made it maintain the lock for longer, but only for several minutes, not enough for a lossmap scan (can take up to an hour). Using the WFS information I manually realigned the IMC, which made locking easier but wouldn't help with staying locked.

For the PMC: The PZT feedback signal had railed and the PMC had been unlocked for 8+ hours. The PMC medm screen controls were generally responsive (I could see the modes on the CCDs changing) but I just couldn't get it locked. c1psl was responding to ping but refusing telnet so I keyed the crate, followed by a burt restore and finally it worked.

After the PMC came back the IMC has already maintained lock for more than an hour, so I'm now running the first lossmap measurements.

  13306   Mon Sep 11 12:40:32 2017 johannesUpdatePSLPSL table auxiliary NPRO

I changed the PSL table auxiliary laser setup to the 200 MHz AOM and put the light back in the fiber. Coupling efficiency is again ~50%, giving us up to about 75 mW of auxiliary laser light on the AS table. The 90% to 10% fall time of the light power out of the fiber when switched off is 16.5 ns with this AOM on the PDA10A, which will be sufficient for the ringdown measurements.

  13305   Mon Sep 11 09:47:53 2017 SteveUpdateGeneralWIMA caps refilled

Instock WIMA caps refilled to a minimum 50 pieces each.

Attachment 1: WIMA.png
WIMA.png
  13304   Fri Sep 8 12:08:32 2017 GabrieleSummaryLSCGood reconstruction of PRMI degrees of freedom with deep learning

Introduction

This is an update of my previous reports on applications of deep learning to the reconstruction of PRMI degrees of freedom (MICH/PRCL) from real free swinging data. The results shown here are improved with respect to elog 13274 and 13294. The training is performed in two steps, the first one using simulated data, and the second one fine tuning the parameters on real data.

First step: training with simulation

This step is exactly the same already described in the previous entries and in my talks at the CSWG and LVC. For details on the DNN architecture please refer to G1701455 or G1701589. Or if you really want all the details you can look at the code. I used the following signals as input to the DNN: POPDC, POP22_Q, ASDC, REFL11_I/Q, REFL55_I/Q, AS55_I/Q. The network is trained using linear trajectories in the PRCL/MICH space, and signals obtained from a model that simulates the PRMI behavior in the plane wave approximation. A total of 150000 trajectories are used. The model includes uncertainties in all the optical parameters of the 40m PRMI configuration, so that the optical signals for each trajectory are actually computed using random optical parameteres, drwn from gaussian distributions with proper mean and width. Also, white random gaussian sensing noise is added to all signals with levels comparable to the measured sensing noise.

The typical performance on real data of a network pre-trained in this way was already described in elog 13274, and although being reasoble, it was not too good.

Second step: training with real data

Real free swinging data is used in this step. I fine tuned the demodulation phases of the real signals. Please note that due to an old mistake, my convention for phases is 90 degrees off, so for example REFL11 is tuned such that PRCL is maximized in Q instead of I. Regardless of this convention confusion, here's how I tuned the phases:

  • REFL11: PRCL is all in Q when crossing the carrier resonance
  • REFL55: PRCL is all in Q when crossing the carrier resonance
  • AS55: MICH is all in Q when crossing the PRCL carrier resonance
  • POP22: signal peaking in Q when crossing carrier or sideband resonances. Carrier resonance crossing gives positive sign

Then I built the following training architecture. The neural network takes the real signals and produces estimates of PRCL and MICH for each time sample. Those estimates are used as the input for the PRMI model, to produce the corresponding simulated optical signals. My cost function is the squared difference of the simulated versus real signals. The training data is generated from the real signals, by selection 100000 random 0.25s long chunks: the history of real signal over the whole 0.25s is used as input, and only the last sample is used for the cost function computation. The weights and biases of the neural network, as well as the model parameters are allowed to change during the learning process. The model parameters are regularized to suppress large deviations from the nominal values.

One side note here. At first sight it might seems weird that I'm actually fedding as input the last sample and at the same time using it as the reference for the loss function. However, you have to remember that there is no "direct" path from input to output: instead all goes through the estimated MICH/PRCL degrees of freedom, and the optical model. So this actually forces the network to tune the reconstruction to the model. This approach is very similar to the auto-encoder architectures used in unsupervised feature learning in image recognition.

Results

After trainng the network with the two previous steps, I can produce time domain plots like the one below, which show MICH and PRCL signals behaving reasonably well:

To get a feeling of how good the reconstruction is, I produced the 2d maps shown below. I divided the MICH/PRCL plane in 51x51 bins, and averaged the real optical signals with binning determined by the reconstructed MICH and PRCL degrees of freedom. For comparison the expected simulation results are shown. I would say that reconstructed and simulated results match quite well. It looks like MICH reconstruction is still a bit "compressed", but this should not be a big issue, since it should still work for lock acquisition.

Next steps

There a few things that can be done to futher tune the network. Those are mostly details, and I don't expect significant improvements. However, I think the results are good enough to move on to the next step, which is the on-line implementation of the neural network in the real time system.

  13303   Fri Sep 8 10:22:30 2017 SteveUpdatePEMtemp sensor update

The weight of SS can with copper liner  is 12.2 kg

Is 1 Amp for the heating jacket going to be enough? We should have some headroom.

Quote:

to get the sensors to read the same values they have to be in direct thermal contact with the metal block - there can't be any adapter board in-between

for the 2nd attempt, I also recommend encasing it in a metal block rather than just one side. You can drill some 7-10 mm diameter holes in an aluminum or copper block. Then put the sensors in there and plug it up with some thermal paste.

 

  13302   Fri Sep 8 07:54:04 2017 SteveUpdatePEMM8.1 eq

Nothing tripped. No obvious damage.

Attachment 1: M8.1.png
M8.1.png
  13301   Thu Sep 7 23:09:00 2017 johannesUpdatePSLPSL table auxiliary NPRO

I brought the DEI Pulser unit and a suitable Pockels cell over from Bridge today (I also found an identical Pockels cell already at the 40m on the SP table, now that I knew what to look for).

I also brought the 200MHz AOM (Crystal Technology 3200-1113) along which can achieve rise times of 10 ns(!). Before I start setting up the Pockels cell I wanted to try this different AOM and look at its switching behavior. It asks for a much smaller beam (<65 um diam.) than what's currently in the path to the fiber (500 um diam.), although it's clear aperture is technically big enough (~1mm diam.). So I still tried, and the result was a somewhat elliptical deflected beam, and the slower decay was again visible after switching the RF input.

I was using the big Fluke function generator for the 200MHz seed signal, a Mini Circuits ZASWA-2-50 switch and a Mini Circuits ZHL-5W-1 amplifier. For the last two I moved two power supplies (+/-5V for the switch and +24V for the amplifier) into the PSL enclosure. I started at low seed power on the Fluke, routing the amplified signal into a 20dB attenuator before measuring it with an RF power meter. The AOM saturates at 2.5W (34 dBm), which I determined is achieved with a power setting on the Fluke of -4 dBm. As expected, this AOM performed faster (~80ns fall time) but I again observed the slower decay.

This struck me as weird and I started swapping components other than the AOM, which I probably should have done before. It turned out that it was the PD I was using (the same PDA10CF Gautam had used for his MC ringdown investigations). When I changed it to a PDA10A (Si diode, 150MHz bandwidth) the slow decay vanished! One last round of crappy screenshots:

   

Rather than proceeding with the Pockels cell, tomorrow I will make the beam in the AOM smaller and hope that that takes care of the ellipticity. If it does: the AOM can theoretically switch on ~10ns timescale, same for the switch (5-15ns typical), and the amplifier is non-resonant and works up to 500MHz, so it shouldn't be a limiting factor either. If this doesn't work out, we can still have ~100ns switching times with the other AOMs.

  13300   Wed Sep 6 23:06:30 2017 gautamUpdateLSCCoil de-whitening switching investigation

Summary:

Rana suggested checking if the coil de-whitening switching is actually happening in the analog path. I repeated the test detailed hereAttachments #1 and #2 suggest that all the coils for the BS and ITMs are indeed switching yes.

Details:

  • The motivation behind this test was the following - the analog path switching is done by applying some logic voltage to a switch, but if this voltage is common among many switches, the hypothesis was that perhaps individual switches were not getting the required voltage to engage the switching.
  • This time FM9 (simulated de-whitening) and FM10 (inverse de-whitening) in the coil output filter modules turned off, so as to maintain a flat TF in the digital domain, but engage the de-whitened analog path (turning off FM9 is supposed to do this).
  • There is poor coherence in the measurement above 40Hz so the data there should be neglected. It is hard to get a good measurement at higher frequencies because of the pendulum TF + heavy low pass filtering from the analog de-whitening path.
  • But between 10-40Hz, we already see the analog de-whitening TF in the measurement.
  • For comparison, I have plotted the measured pendulum TFs for one of the coils from an earlier test (all the coils were roughly at the same level).

So it would seem that there is some other noise which has a 1/f^2 shape and is at the same level we expected the DAC noise to be at. Rana suggested checking coherence with MC transmission to see if this could be laser intensity noise.

I also want to re-do the actuator calibrations for the vertex optics again before re-posting the revised noise budget.

Attachment 1: BScoils.pdf
BScoils.pdf
Attachment 2: ITMcoils.pdf
ITMcoils.pdf
  13299   Wed Sep 6 01:09:11 2017 johannesUpdateComputer Scripts / ProgramsNew set of loss measurements

I stumbled upon a faster way to stream data from the TDS3014 oscilloscopes to disk, which speeds the loss measurements up by a lot:  ftp://sprite.ssl.berkeley.edu/pub/sharris/MAVEN_LPW_Preamp/109_TDS3014B_control/tds3014b.py
This convenient(!) set of scripts contains a function that parses the scope's native binary format, for which the acquisition of 1 screenful of data takes <1s as opposed to ~20s, into readable data. I tested it for a bit and concluded that it does what it actually claims to do, but there's one weirdness: It get's the channel offset wrong. However this doesn't matter in our measurement because we're subtracting the dark level, which sees the same (wrong) offset. Other than that it seems okay.

So I started a new set of armloss measurements, and since the data acquisition is now much faster, I was able to squeeze a set of 20 individual measurements for each arm into ~30 minutes. This is the procedure I follow when I take these measurements for the XARM (symmetric under XARM <-> YARM):

  1. Dither-align the interferometer with both arms locked. Freeze outputs when done.
  2. Misalign ETMY + ITMY.
  3. ITMY needs to be misaligned further. Moving the slider by at least +0.2 is plentiful to not have the other beam interfere with the measurement.
  4. Start the script, which does the following:
    1. Resume dithering of the XARM
    2. Check XARM dither error signal rms with CDS. If they're calm enough, proceed.
    3. Freeze dithering
    4. Start a new set of averages on the scope, wait T_WAIT (5 seconds)
    5. Read data (= ASDC power and MC2 trans) from scope and save
    6. Misalign ETMX and wait 5s
    7. Read data from scope and save
    8. Repeat desired amount of times
  5. Close the PSL shutter and measure the PD dark levels

I will write a more comprehensive post describing the data acquisition and processing, let's just look at the results for now: The "uncertainties" reported by the individual measurements are on the order of 1-2 ppm (~1.9 for the XARM, ~1.3 for the YARM). This accounts for fluctuations of the data read from the scope and uncertainties in mode-matching and modulation depths in the EOM. I made histograms for the 20 datapoints taken for each arm: the standard deviation of the spread is a little over 2ppm. We end up with something like:

XARM: 49.3 +/- 2.1 ppm
YARM: 20.3 +/- 2.3 ppm

 

    

Attachment 1: XARM_20170905.pdf
XARM_20170905.pdf
Attachment 2: YARM_20170905.pdf
YARM_20170905.pdf
  13298   Tue Sep 5 23:13:44 2017 johannesUpdatePSLPSL table auxiliary NPRO

I used Gautam's mode measurement of the auxiliary NPRO (w=127.3um, z=82mm) for the spacing of the optics on the PSL table for the fiber injection and light modulation. As mentioned in previous posts, for the time being there is no Faraday isolator and no broadband EOM installed, but they're accounted for in the mode propagation and they have space reserved if desired/required/available.

The coupler used for the injection is a Thorlabs F220APC-1064, which allegedly collimates the beam from the fiber type we use to 2.4mm diameter, which I used as the target for the mode calculations. I coupled the first order diffracted beam to a ~60m fiber, which is a tad long but the only fiber I could locate that was long enough. The coupling efficiency from free-space to fiber is 47.5%, and we can currently get up to 63 mW out of the fiber.

Tomorrow Steve and I are going to pull the fiber through protective tubing and bring it to the AS port. The next step is then characterizing the beam out of the collimator to match it into the interferometer.

As far as the switching itself is concerned: I confirmed that the exponential decay is still present when looking at the fiber output. I located the DEI Pulser unit in the QIL lab, and also found several more AOMs, including a 200MHz Crystal Technologies one, same brand that the PSL has, where the ringdown was not observed. According to past elogs, with good polarizers we can expect an extinction ratio of ~200 from the Pockels cell, which should be fine, but it's going to be tradeoff switching speed <-> extinction (if the alternate AOM doesn't show this ringdown behavior).

Attachment 1: PSL_IR.pdf
PSL_IR.pdf
Attachment 2: psl_aux_laser.pdf
psl_aux_laser.pdf
  13297   Tue Sep 5 23:02:37 2017 gautamUpdateCDSslow machine bootfest

MC autolocker was not working - PCdrive was railed at its upper rail for ~2 hours judging by the wall StripTool trace. I tried restarting the init processes on megatron, but that didn't fix the problem. The reason seems to have been related to c1iool0 failing - after keying the crate, autolocker came back fine and MC caught lock almost immediately.

Additionally, c1susaux, c1auxex,c1auxey and c1iscaux are also down. I'm not planning on using the IFO tonight so I am not going to reboot these now.

 

  13296   Tue Sep 5 17:52:06 2017 KiraUpdatePEMtemp sensor update

to get the sensors to read the same values they have to be in direct thermal contact with the metal block - there can't be any adapter board in-between

for the 2nd attempt, I also recommend encasing it in a metal block rather than just one side. You can drill some 7-10 mm diameter holes in an aluminum or copper block. Then put the sensors in there and plug it up with some thermal paste.

  13295   Tue Sep 5 17:18:17 2017 KiraUpdatePEMtemp sensor update

Today, I stuck on the sensors to a metal block using a flag, rubber bands, and some thermal paste (1st attachment). I then wrapped the whole thing in about 4 layers of insulation and a lot of tape (2nd attachment). The only things leading out of the box were the three connections to the sensors and a thermometer. I then connected the wires to their respective places on the board of the sensor. To get the readings out we would need to use an ADC. Gautam and I checked to make sure the ADC we have inside the lab goes from -10V to 10V so that it would be able to measure the 3V value the sensor typically measures. We then tried to connect all three sensors to a DC source simultaneously, but unfortunately one of them seems to have disconnected somewhere during the process, as it only showed 1.2V instead of 3V. I plan to fix this tomorrow morning so that we can hopefully set this up soon.

Quote:

I took off the AD590 and attached it to two long wires leading out from the board. This will allow us to attach the sensor to a metal block and not have to stick the whole board to it. I have also completed three identical copies of this and it's pretty much ready to be tested. According to Craig and Andrew's elog here, the sensor is very noisy and they added in a low pass filter to fix that, so that's something to consider for the final version of the circuit. I'll test what I have so far and see how that goes. We still need to figure out how to get readings from the sensors.

To attach the sensor to the metal block, I'll use some thermal paste and fasteners. I'll also put a thermometer on the block to record the actual temperature. I'll then wrap it in some insulation we have in the lab and have only some wires leading out of it to make measurements. I'll leave this setup overnight and record the outputs for about a full day. The fluctuations between the sensors will then indicate the noise of each individual sensor.

 

Attachment 1: IMG_20170905_144924.jpg
IMG_20170905_144924.jpg
Attachment 2: IMG_20170905_165042.jpg
IMG_20170905_165042.jpg
  13294   Tue Sep 5 16:37:47 2017 GabrieleSummaryLSCImproved PRMI deep learning reconstruction

This is an update on the results already presented earlier (refer to elog 13274 for more introductory details). I improved significantly the results with the following tricks:

  • I retuned the demodulation phase of AS55, this time ensuring that the (alleged) MICH motion is visible mostly in Q when crossing a carrier resonance. Further fine tunings of phases will be possible once we have a measurement of the length optical matrix

  • I fine tuned the netwrok by training it again using the real data. The ides is the following. I started with the network trained on the simulated data, and froze the parameters of the input recurrent layers. I fed the real signal to the network, computed the reconstructed PRCL/MICH, and fed them to my PRMI model to compute simulated signals. I allowed some of the parameters of the models to vary (expecially demodulation phases). I then trained again the network by trying to match the model predicted signals with the real input signals. I allowed only the parameters of the fully connected layers to vary (mostly for technical reasons, I'm working on re-training also the recurrent layers)

An example of time domain reconstruction is visible below. It already looks better than the old results:

As before, to better evaluate the performance I plotted averaged values of the real signals as a function of the reconstructed MICH and PRCL positions. The results are compared with simulation below. They match quite well (left real data, right simualtion expectation)

One thing to better understand is that MICH seems to be somewhat compressed: most of the output values are between -100 and +100 nm, instead of the expected -lambda/4, lambda/4. The reason is still unclear to me. It might be a bug that I haven't been able to track down yet.

  13293   Tue Sep 5 14:41:58 2017 gautamUpdateCDSNDS2 server restarted on megatron

I was unable to download data using nds2. Gabriele had reported similar problems a week ago but I hadn't followed up on this.

I repeated steps 5-7 from elog 13161, and now it seems that I can get data from the nds2 servers again. Unclear why the nds2 server had to be restarted. I wonder if this is somehow related to the mysterious acromag EPICS server tmux session dropout.

  13292   Tue Sep 5 09:47:34 2017 KiraSummaryPEMheater circuit calculations

I decided to calculate the fluctuation in power that we will have in the heater circuit. The resistors we ordered have 50 ppm/C and it would be useful to know what kind of fluctuation we would expect. For this, I assumed that the heater itself is an ideal resistor that has no temperature variation. The circuit diagram is found in Kevin's elog here. At saturation, the total resistance (we will have a 1\Omega resistor instead of 6\Omega for our new design) will be R_{tot}=R+R_{h}=1\Omega +24\Omega =25\Omega. Therefore, with a 24V input, the saturation current should be I=\frac{V_{in}}{R_{tot}}=\frac{24V}{25\Omega}=0.96A.  Therefore, the power in the heater should be (in the ideal case) P=I^2R{_{h}}=22.1184W

Now, in the case where the resistor is not ideal, let's assume the temperature of the resistor changes by 10C (which is about how much we would like to heat the whole thing). Therefore, the resistor will have a new value of R_{new}=R+50ppm/C\times 10C\times 10^{-6}=1.0005\Omega. The new current will then be I_{new}=\frac{V_{in}}{R_{new}}=0.95998A and the new power will be P_{new}=I_{new}^{2}R_{h}=22.1175W. So the difference in power going through the heater is about 0.00088W.

We can use this power difference to calculate how much the temperature of the metal can we wish to heat up will change. \Delta T=\Delta P\times (1/\kappa) /x where \kappa is the thermal conductivity and x is the thickness of the material. For our seismometer, I calculated it to be 0.012K.

  13291   Tue Sep 5 02:07:49 2017 gautamUpdateLSCLow Noise DRMI attempt

Summary:

Tonight, I was able to lock the DRMI, turn on the whitening filters for the sensing PDs, and also turn on the coil de-whitening filters for ITMX, ITMY and BS. However, I didn't see the expected improvement in the MICH spectrum between ~50-300 Hz sad. Sad.

Details:

I basically went through the list of tasks I made in the previous elog. Some notes:

  • The UGF servos suggested that I had to lower the SRCL gain. I lowered it from -0.055 to -0.025. OLTF measurement using In1/In2 method suggested UGF ~120Hz. I don't know why this should be. Plot to be uploaded later.
  • Since we aren't actuating on the ITMs, I was able to leave their coils de-whitened all the time.
  • For the BS, it was trickier - I had to play around a little with the "Tolerance" setting in Foton while looking at transients (using DTT, not a scope for now) while switching the filters.
  • This transition isn't so robust yet - but eventually I found a setting that worked, and I was able to successfully turn on the de-whitening thrice tonight (but also failed about the same number of times). [GV Oct 6 2017: Remember that the PD whitening has to be turned on for this transition to be successful - otherwise the RMS from the high frequencies saturate the DAC.]
  • The locks were pretty stable. One was ~10mins, one was ~15mins, and I broke both deliberately because I was out of ideas as to why the part of the MICH error signal spectrum that I thought was due to DAC noise didn't improve.
  • I've made a bunch of shell scripts to help with the various switchings - but now that I think of it, I should make these python scripts.

Attachment #1: Comparison of MICH_ERR with and without the BS de-whitening. Note that the two ITMs have their coils de-whitened in both sets of traces.

Attachment #2: Spectra of MICH output and one of the BS coil outputs in both states. The DAC RMS increases by ~30x when the de-whitening is engaged, but is still well within limits.

So it looks like the switching of paths is happening correctly. The "CDS BIO STATUS" MEDM screen also shows the appropriate bits toggling when I turn the de-whitening on/off. There is no broadband coherence with MCF between 50-300 Hz so it seems unlikely that this could be frequency noise.

Clearly I am missing something. But anyways I have a good amount of data, may be useful to put together the post CDS/electronics modification DRMI noise budget. More analysis to follow.

 

Attachment 1: MICH_err_comp.pdf
MICH_err_comp.pdf
Attachment 2: deWhitenedCoil.pdf
deWhitenedCoil.pdf
  13290   Mon Sep 4 18:18:29 2017 ranaUpdateLSCdewhite switching: FOTON settings

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

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

 

  13289   Mon Sep 4 16:30:06 2017 gautamUpdateLSCOplev loop tweaking

Now that the DRMI locking seems to be repeatable again, I want to see if I can improve the measured MICH noise. Recall that the two dominant sources of noise were

  1. BS Oplev loop A2L - this was the main noise between 30-60Hz.
  2. DAC noise - this dominated between ~60-300Hz, since we were operating with the de-whitening filters off.

In preparation for some locking attempts today evening, I did the following:

  1. Added steeper elliptic roll-off filters for the ITMX and ITMY Oplevs. This is necessary to allow the de-whitening filters to be turned on without railing the DAC.
  2. Modified the BS Oplev loop to also have steeper high-frequency (>30Hz) roll off. The roll-off between 15-30Hz is slightly less steep as a result of this change.
  3. Measured all Oplev loop TFs - UGFs are between 4 Hz and 5 Hz, phase margin is ~30degrees. I did not do any systematic optimization of this for today.
  4. Went into the Foton filter banks for all the coil output filters, and modified the "Output" settings to be on "Input crossing", with a "Tolerance" of 10 and a "Timeout" of 3 seconds. These settings are to facilitate smooth transition between the two signal paths (without and with coil-dewhitening). The parameters chosen were arbitrary and not optimized in any systematic manner.
  5. After making the above changes, I tried engaging the de-whitening filters on ITMX, ITMY and BS with the arms locked. In the past, I was unable to do this because of a number of issues - Oplev loop shapes and Foton settings among them. But today, the switching was smooth, the single arm locks weren't disturbed when I engaged the coil de-whitening.

Hopefully, I can successfully engage a similar transition tonight with the DRMI locked. The main difference compared to this daytime test is going to be that the MICH control signal is also going to be routed to the BS.

Tasks for tonight, if all goes well:

  1. Lock DRMI.
  2. Use UGF servos to set the overall loop gains for DRMI DoFs.
  3. Reduce PRCL->MICH and SRCL->MICH coupling.
  4. Measure loop shapes of all DRMI DoFs.
  5. Make sensing matrix measurement.
  6. Engage coil-dewhitening, download data, make NB.

Unrelated to this work: the PMC was locked near the upper rail of the PZT, so I re-locked it closer to the middle of the range.

Quote:

Surprisingly, there was no evidence of REFL55 behaving weirdly tonight, and I was able to easily lock the DRMI on 1f error signals using the recipe I've been using in the last few months.

  13288   Fri Sep 1 19:15:40 2017 gautamUpdateALSFiber ALS noise measurement

Summary:

I did some work today to see if I could use the IR beat for ALS control. Initial tests were encouraging.

I will now embark on the noise budgeting.

Details:

  • For this test, I used the X arm
  • I hooked up the X-arm + PSL IR beat to the X-arm DFD channel, and used the Y-arm DFD channels to simultaneously monitor the X-arm green beat.
  • I then transitioned to ALS control and used POX as an out-of-loop sensor for the ALS noise.
  • Attachment #1 shows a comparison of the measurements. In red is the IR beat, while the green traces are from the test EricQ and I did a couple of nights ago using the green beat.
  • I also wanted to do some arm cavity scans with the arm under ALS control with the IR beat - but was unsucessful. The motivation was to fix the ALS model counts->Hz calibration factors.
  • I did however manage to do a 10 FSR scan using the green beatnote - however, towards the end of this scan, the green beat frequency (read off the control room analyzer) was ~140MHz, which I believe is outside (or at least on the edge) of the bandwidth of the Green BBPDs. The fiber coupled IR beat photodiodes have a much larger (1GHz) spec'd bandwidth.

I am leaving the green beat electronics on the PSL table in the switched state for further testing...

 

Attachment 1: IR_ALS_noise.pdf
IR_ALS_noise.pdf
  13287   Fri Sep 1 16:55:27 2017 gautamUpdateComputersTestpoints now accessible again

Thanks to Jonathan Hanks, it appears we can now access test-points again using dataviewer.

I haven't done an exhaustive check just yet, but I have loaded a few testpoints in dataviewer, and ran a script that use testpoint channels (specifically the ALS phase tracker UGF setting script), all seems good.

So if I remember correctly, the major CDS fix now required is to solve the model unloading issue.

Thanks to Jamie/Jonathan Hanks/KT for getting us back to this point! Here are the details:

After reading logs and code, it was a simple daqdrc config change.

The daqdrc should read something like this:

...
set master_config=".../master";
configure channels begin end;
tpconfig ".../testpoint.par";
...


What had happened was tpconfig was put before the configure channels
begin end.  So when daqd_rcv went to configure its test points it did
not have the channel list configured and could not match test points to
the right model & machine.  Dave and I suspect that this is so that it
can do an request directly to the correct front end instead of a general
broadcast to all awgtpman instances.

Simply reordering the config fixes it.

I tested by opening a test point in dataviewer and verifiying that
testpoints had opened/closed by using diag -l.  Xmgr/grace didn't seem
to be able to keep up with the test point data over a remote connection.

You can find this in the logs by looking for entries like the following
while the daqd is starting up.  When we looked we saw that there was an
entry for every model.

Unable to find GDS node 35 system c1daf in INI fiels
  13286   Fri Sep 1 16:27:39 2017 gautamUpdateSUSMC1 glitching

I re-enabled the MC SUS damping and IMC locking for some IFO work just now.

Quote:

MC1, MC2 and MC3 damping turned off to see glitching action at 9:57am

 

  13285   Fri Sep 1 15:46:12 2017 KiraUpdatePEMtemp sensor update

I took off the AD590 and attached it to two long wires leading out from the board. This will allow us to attach the sensor to a metal block and not have to stick the whole board to it. I have also completed three identical copies of this and it's pretty much ready to be tested. According to Craig and Andrew's elog here, the sensor is very noisy and they added in a low pass filter to fix that, so that's something to consider for the final version of the circuit. I'll test what I have so far and see how that goes. We still need to figure out how to get readings from the sensors.

To attach the sensor to the metal block, I'll use some thermal paste and fasteners. I'll also put a thermometer on the block to record the actual temperature. I'll then wrap it in some insulation we have in the lab and have only some wires leading out of it to make measurements. I'll leave this setup overnight and record the outputs for about a full day. The fluctuations between the sensors will then indicate the noise of each individual sensor.

Attachment 1: IMG_20170901_144729.jpg
IMG_20170901_144729.jpg
  13284   Fri Sep 1 08:25:08 2017 SteveUpdateSUSMC1 glitching

MC1, MC2 and MC3 damping turned off to see glitching action at 9:57am

Quote:

There was a pretty large glitch in MC1 about an hour ago. The misalignment was so large that the autolocker wasn't able to lock the IMC. I manually re-aligned MC1 using the bias sliders, and now IMC locks fine. Attached is a 90 second plot of 2K data from the OSEMs showing the glitch. Judging from the wall StripTool, the IMC was well behaved for ~4 hours before this glitch - there is no evidence of any sort of misalignment building up, judging from the WFS control signals.

 

Attachment 1: MC1glitching.png
MC1glitching.png
Attachment 2: MC1kicks.png
MC1kicks.png
  13283   Thu Aug 31 21:40:24 2017 gautamUpdateGeneralMC1 kicked again

There was a pretty large glitch in MC1 about an hour ago. The misalignment was so large that the autolocker wasn't able to lock the IMC. I manually re-aligned MC1 using the bias sliders, and now IMC locks fine. Attached is a 90 second plot of 2K data from the OSEMs showing the glitch. Judging from the wall StripTool, the IMC was well behaved for ~4 hours before this glitch - there is no evidence of any sort of misalignment building up, judging from the WFS control signals.

Attachment 1: MC1_glitch.png
MC1_glitch.png
  13282   Thu Aug 31 18:36:23 2017 gautamUpdateCDSrevisiting Acromag

Current status:

  • There is a single Acromag ADC unit installed in 1X4
  • It is presently hooked up to the PSL NPRO diagnostic connector channels
  • I had (re)-started the acquisiton of these channels on August 16 - but for reasons unknown, the tmux session that was supposed to be running the EPICS server on megatron seems to have died on August 22 (judging by the trend plot of these channels, see Attachment #1)
  • I had not set up an upstart job that restarts the server automatically in such an event. I manually restarted it for now, following the same procedure as linked in my previous elog.
  • While I was at it, I also took the opportunity to edit the Acromag channel names to something more appropriate - all channels previously prefixed with C1:ACRO- have now been prefixed with C1:PSL-

Plan of action:

  1. Hardware - we have, in the lab, in addition to the installed ADC unit
    • 3x 8 channel differential input ADC units
    • 2x 8 channel differential output DAC units
    • 1x 16 channel BIO unit
    • 2U chassis + connectors + breakout boards + other misc hardware that I think Johannes and Lydia procured with the original plan to replace the EX slow controls.
    • Some relevant elogs: Panel designs, breakout design, sketch for proposed layout, preliminary channel list.
      So on the hardware side, it would seem that we have everything we need to go ahead with replacing the EX slow controls with an Acromag system, although Johannes probably knows more about our state of readiness from a hardware PoV.
  2. Software
    • We probably want to get a dedicated machine that will handle the EPICS channel serving for the Acromag system
    • Have to figure out the networking arrangement for such a machine
    • Have to figure out how to set up the EPICS server protocol in such a way that if it drops for whatever reason, it is automatically restarted

 

Attachment 1: Acromag_EPICS.png
Acromag_EPICS.png
  13281   Thu Aug 31 03:31:15 2017 gautamUpdateLSCDRMI re-locked!

After our Demod/Whitening electronics investigations suggested nothing obviously wrong, I decided to give DRMI locking another go tonight.

Surprisingly, there was no evidence of REFL55 behaving weirdly tonight, and I was able to easily lock the DRMI on 1f error signals using the recipe I've been using in the last few months.

Not sure what to make of all this frown.

I got in a ~15 minute lock, but I wasn't prepared to do any sort of characterization/ sensing / attempt to turn on coil-dewhitening, and I'm too tired to try again tonight. I was however able to whiten the error signals, as I have been able to do in the past. There is a ~45Hz bump in MICH that I haven't seen in the past.

I'll try and do some characterization tomorrow eve, but it's encouraging to at least get back to the pre-FB-failure state of locking.

Attachment 1: DRMI_1f.png
DRMI_1f.png
Attachment 2: DRMI_relocked.pdf
DRMI_relocked.pdf
  13280   Thu Aug 31 00:52:52 2017 gautamUpdateLSCREFL55 whitening board debugging

[rana,gautam]

We did an ingenious checkup of the whitening board tonight.

  • The board is D990694
  • We made use of a tip-tilt DAC channel for this test (specifically TT1 UL, which is channel 1 on the AI board). We disconnected the cable going from the AI board to the TT coil driver board.
    • as opposed to using a function generator to drive the whitening filter, this approach allows us to not have to worry the changing offsets as we switch the whitening gain.
    • By using the CDS system to generate the signal and also demodulate it, we also don't have to worry about the drive and demod frequencies falling out of sync with each other.
  • The test was done by injecting a low frequency (75.13 Hz, amplitude=0.1) excitation to this DAC channel, and using the LSC sensing matrix infrastructure to demodulate REFL55 I and Q at this frequency. Demod phases in these servos were adjusted such that the Q phase demodulated signal was minimized.
  • An excitation was injected using awggui into TT1 UL exc channel.
  • We then stepped the whitening gains for REFL55_I and REFL55_Q in 3dB steps, waiting 5 seconds for each step. Syntax is z step -s 5 C1:LSC-REFL55_I_WhiteGain +1.0,15 C1:LSC-REFL55_Q_WhiteGain +1.0,15
  • Attachment #1 suggests that the whitening filter board is working as expected (each step is indeed 3dB and all steps are equal to the eye).
  • Data + script used to generate this plot is in Attachment #2.

I've restored all connections at that we messed with at the LSC rack to their original positions.

The TT alignment seems to be drifting around more than usual after we disconnected one of the channels - when I came in today afternoon, the spot on the AS camera had drifted by ~1 spot diameter so I had to manually re-align TT1. 

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Based on my tests, everything on the Demod board seems to work as expected. I need to think more about what else could be happening here - specifically do a more direct test on the whitening board.

Attachment 1: REFL55_whtCheck.pdf
REFL55_whtCheck.pdf
Attachment 2: REFL55_whtChk.tar.gz
  13279   Thu Aug 31 00:46:57 2017 ranaSummaryCDSallegra -> Scientific Linux 7.3

I made a 'LiveCD' on a 16 GB USB stick using this command after the GUIs didn't work and looking at some blog posts:

sudo dd if=SL-7.3-x86_64-2017-01-20-LiveCD.iso of=/dev/sdf

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Debian doesn't like EPICS. Or our XY plots of beam spots...Sad!

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No, not confused on that point. We just will not be testing OS versions at the 40m or running multiple OS's on our workstations. As I've said before, we will only move to so-called 'reference' systems once they've been in use for a long time.

Ubuntu16 is not to my knowledge used for any CDS system anywhere.  I'm not sure how you expect to have better support for that.  There are no pre-compiled packages of any kind available for Ubuntu16.  Good luck, you big smelly doofuses. Nyah, nyah, nyah.

K Thorne recommends that we use SL7.3 with the 'xfce' window manager instead of the Debian family of products, so we'll try it out on allegra and rossa to see how it works for us. Hopefully the LLO CDS team will be the tip of the spear on solving the usual software problems we have when we "~up" grade.

  13278   Thu Aug 31 00:19:35 2017 rana[^r]UpdatePSLIMC/FSS FAST gain

nominal changed from 22 to 23 dB to minimize PC drive RMS

previous loop gain measurement is sort of bogus (made on SR785); need some 4395 loop measurements and checking of crossover and error point spectrum

  13277   Wed Aug 30 22:15:47 2017 ranaOmnistructureComputersUSB flash drives moved

I have moved the USB flash drives from the electronics bench back into the middle drawer of the cabinet next to the AC which is west of the fridge. Drawer re-enlabeled.

ELOG V3.1.3-