ID |
Date |
Author |
Type |
Category |
Subject |
13917
|
Tue Jun 5 20:31:42 2018 |
rana | Update | Cameras | Update on GigE Cameras |
Aha! Video is back!
I think it would be good to add a flag whereby the video can be saved to disk in some uncompressed video format (ogg, avi, ?) instead of displayed to a matplotlib window. We could then use the default to just display video, but use the save-to-disk flag to grab a few minutes of video for image processing.
Quote: |
In the meantime, I've impemented a simple Python video feed streamer which does work, and which students can use as a base framework to implement more complicated things (e.g., stream multiple feeds in one window, save a video stream movie or animation).
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13960
|
Thu Jun 14 00:46:09 2018 |
rana | Update | IOO | WFS HEAD SW confusion |
its painful, but you and I should probably take these out, bypass the switches and use them with fixed gain; the 'Reed Relay' attenuators are not a good part for this app.
The historical problem is that they tend to self oscillate with full gain because they had 2 MAX4106 in series which couple to each other in the bad way --- need to remove one of them and set the gain of the other one to 10.
Quote: |
The unfortunate discovery today was that the attenuator switches on the IMC WFS heads are actually assigned to individual segments, and they are active. That means that we have been running the WFS with an uneven gain setting.
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14023
|
Tue Jun 26 22:06:33 2018 |
rana | Update | Computers | rossa: SL7.3 upgrade continues: DTT is back |
I used the following commands to get diaggui to run on rossa/SL7:
controls@rossa|lib64> ls -lrt libsasl*
-rwxr-xr-x. 1 root root 121296 Feb 16 2016 libsasl2.so.3.0.0
lrwxrwxrwx. 1 root root 17 Dec 18 2017 libsasl2.so -> libsasl2.so.3.0.0
lrwxrwxrwx. 1 root root 17 Dec 18 2017 libsasl2.so.3 -> libsasl2.so.3.0.0
controls@rossa|lib64> sudo ln -s libsasl2.so.3.0.0 libsasl2.so.2
controls@rossa|lib64> ls -lrt libsasl*
-rwxr-xr-x. 1 root root 121296 Feb 16 2016 libsasl2.so.3.0.0
lrwxrwxrwx. 1 root root 17 Dec 18 2017 libsasl2.so -> libsasl2.so.3.0.0
lrwxrwxrwx. 1 root root 17 Dec 18 2017 libsasl2.so.3 -> libsasl2.so.3.0.0
lrwxrwxrwx. 1 root root 17 Jun 26 22:02 libsasl2.so.2 -> libsasl2.so.3.0.0
Basically, I have set up a symbolic link to point sasl2.so.2 to sasl2.so.3.0.0. I've asked LLO again for some guidance on whether or not to find some backport in a non-standard SL7 repo. IF they reply, we may later replace this link with a regular file.
For the nonce, diaggui runs and is able to show us the spectra. We also got swept sine to work. But the FOTON launched from inside of AWGGUI doesn't inherit the sample frequency of the excitation channel so we can't filter noise injections from awggui yet. |
14025
|
Wed Jun 27 19:05:20 2018 |
rana | Update | Computers | rossa: SL7.3 upgrade continues: DTT is back |
UNELOGGED: someone has changed Pianosa from Ubuntu/Dumbian into SL7. Might be hackers.
Donatella is now the only Ubuntu machine in the control room. I propose we keep it this way for another month and then go fully SL7 if we find no bugs with Pianosa/Rossa. |
14029
|
Thu Jun 28 10:28:27 2018 |
rana | Update | CDS | vacuum pneumatic N2 pressure |
we disabled logging the N2 Pressure to a text file, since it was filling up disk space. Now it just sends an email to our 40m mailing list, so we'll all get a warning.
The crontab uses the 'bash' version of output redirection '2>&1', which redirects stdout and stderr, but probably we just want stderr, since stdout contains messages without issues and will just fill up again. |
14076
|
Tue Jul 17 12:46:28 2018 |
rana | Update | General | some notes from yesterday |
For the EY, instead of balancing the table, I just moved the weight approximately so that the ETMY OSEMS were at half light, but didn't check the level since ETMY is the only optic.
Some notes on OMC/AS work (Aaron/Gautam can amend/correct):
- Beam is now well centered in OMC MMT. Hits input coupling mirror and cleanly exits the vacuum to the AS table.
- Didn't see much on OMC trans, but PDs are good based on flashlight test.
- just before closing, re-aligned beam in yaw so that it gets close to the east screw on the input coupler. Aaron and I think we maybe saw a flash there with the OMC length PZT being driven at full range by a triangle wave.
- with OMC Undulators (aka tip/tilt PZT mirrors) energized, the beam was low on PZT1 mirror. We pitched ITMY by ~150 micro-rad and that centered the beam on PZT1 mirror. ITMY-OL is probably not better than 100 urad as a DC reference?
- We checked the range of Undulator 1 and we were getting ~5 mrad of yaw of the beam for the full range, and perhaps half of that in pitch. Rob Ward emailed us from Oz to say that the range is robably 2.7 mrad, so that checks out.
Even if the ITMY has to be in the wrong position to get the beam to the OMC, we can still do the heater tests in one position and then do the OMC checkout stuff in the other position.
Gautam suspects that there is a possible hysterical behaviour in the Undulators which is related to the MC3 glitching and the slow machine hangups and also possibly the illuminati.
[aaron]
-We noticed a ghost beam that from MC REFL (MMT2) that should be dumped during the next vent--it travels parallel to the OMC's long axis and nearly hits one of the steering mirrors for OMC refl.
-We measured the level of the table and found it ~3 divisions off from level, with the south end tilted up
-Gautam rotated and slightly translated OM5 to realign the optic, as expected. No additional optics were added.
-Gautam and I tested the TT piezo driver. We found that 3.6V on the driver's input gave 75V (of 150V) at the output, at least for yaw on piezo 1. However, as Gautam mentioned, during testing it seemed that the other outputs may have different (nonzero) offset voltages, or some hysterisis. |
14100
|
Tue Jul 24 06:11:50 2018 |
rana | Update | Cameras | Developing neural networks on simulated video |
This looks like good progress. Instead of fixed sines or random noise, you should generate now a time series for the motion which is random noise but with a power spectrum similar to what we see for the ETM pitch motion in lock. You can use inverse FFT to get the time series from the open loop OL spectra (being careful about edge effects).
Quote: |
Aim: To develop a neural network that resolves mirror motion from video.
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14113
|
Sun Jul 29 20:03:02 2018 |
rana | Update | PEM | Seismometer temp control |
While Shruti is re-building Kira's heater circuit, I looked up how to do one of these (i.e. what does a real EE say about how to build a current source?):
It turns out that there is an Analog Devices application note (AN-968) about this (as there usually is once we get tired of playing around and try to look up the right answer).
I've linked to the note and attached the recommended schematic for high current applications. We'll go ahead as is, but we'll make a PCB according to this App Note for the v3 circuit.
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Attachment 1: Screen_Shot_2018-07-29_at_8.00.27_PM.png
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14127
|
Thu Aug 2 23:09:25 2018 |
rana | Summary | Computers | X Green "Mystery" solved |
I'm going to guess that this was me: I was disconnecting some octopus power strip nonsense down there (in particular illuminators and cameras), so I might have turned off the AUX rack by mistake.
Quote: |
I walked down to the X end and found that the entire AUX laser electronics rack isn't getting any power. There was no elog about this.
I couldn't find any free points in the power strip where I think all this stuff was plugged in so I'm going to hold off on resurrecting this until tomorrow when I'll work with Steve.
Quote: |
The X arm green does not stay locked to the cavity - the alignment looks fine, and the green flashes are strong, but the lock does not hold. This shouldn't be directly connected to anything we did today since the Green PDH servo is entirely analog.
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14130
|
Fri Aug 3 16:27:40 2018 |
rana | Update | SUS | Low noise bias path idea |
Bah! Too complex. |
14177
|
Wed Aug 22 12:22:27 2018 |
rana | Summary | Electronics | Inspection of the possible dual backplane interfaces for Acromag DAQ |
I think we don't need to keep Crystal Ref: we can change this into a regular Wenzel box with no outside control or monitoring.
Quote: |
- Crystal Ref (D980353)
- Schematic source: LIGO DCC D980353
- Assesment: Only P1 (1A-4A) is to be connected to Acromag. (Just one DSub is sufficient)
- P1 1A-4A
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14267
|
Fri Nov 2 12:07:16 2018 |
rana | Update | CDS | NDScope |
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=44971
Let's install Jamie's new Data Viewer |
14290
|
Mon Nov 12 13:53:20 2018 |
rana | Update | IOO | loss measurement: oscope vs CDS DAQ |
sstop using the ssscope, and just put the ssssignal into the DAQ with sssssome whitening. You'll get 16 bitsśšß.
Quote: |
I increased the resolution on the scope by selecting Average (512) mode. I was a bit confused by this, since Yuki was correct that I had only 4 digits recorded over ethernet, which made me think this was an i/o setting. However the sample acquisition setting was the only thing I could find on the tektronix scope or in its manual about improving vertical resolution. This didn't change the saved file, but I found the more extensive programming manual for the scope, which confirms that using average mode does increase the resolution... from 9 to 14 bits! I'm not even getting that many.
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14311
|
Tue Nov 20 17:38:13 2018 |
rana | Update | Upgrade | New Coffee Machine |
Rana, Aaron, Gautam
The old Zojirushi has died. We have received and comissioned our new Technivoorm Mocha Master today. It is good. |
14329
|
Sun Dec 2 19:32:35 2018 |
rana | Update | IOO | fit times |
need to vary start/stop times in fit to test for systematics |
14336
|
Fri Dec 7 19:42:47 2018 |
rana | Frogs | elog | can't upgrade DokuWiki because of PHP / SL7 |
All of our wikis (except the 40m one which unfortunately got turned into ligo.org mess) use DokuWiki. This now has an auto-upgrade feature through the Admin web interface.
I tried this recently and it fails with this message:
DokuWiki 2018-04-22a "Greebo" is available for download.
You're currently running DokuWiki Release 2017-02-19e "Frusterick Manners".
New DokuWiki releases need at least PHP 5.6, but you're running 5.4.16. You should upgrade your PHP version before upgrading!
So we'll have to wait until SL7 (which is what NODUS is running).
I DID do a 'yum upgrade' which updated all the packages. I also installed yum-cron so that the RPM listings get updated daily. But sadly, SL7 only has PHP 5.4.16 (which is a June 2013 release):
> Package php-5.4.16-43.el7_4.1.x86_64 already installed and latest version
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14382
|
Thu Jan 3 21:17:49 2019 |
rana | Configuration | Computers | Workstation Upgrade: Donatella -> Scientific Linux 7.2 |
donatella was one of our last workstations running ubuntu12. we installed SL7 on there today
- had to use a DVD; wouldn't boot from USB stick
- made sure to use userID=1001 and groupID=1001 at the initial install part
- went to the Keith Thorne LLO wiki on SL7
- The 'yum update' command failed due to a gstreamer conflict. I did "yum remove gstreamer1-plugins-ugly-free-1.10.4-3.el7.x86_64" and then it continued a bit more.
-
Then there are ~20 errors related to gds-crtools that look like this:Error: Package: gds-crtools-2.18.12-1.el7.x86_64 (lscsoft-production) Requires: libMatrix.so.6.14()(64bit)
- I re-ran the yum install .... command using the --skip-broken command and that seemed to complete, although I guess the GDS stuff will not work.
- Installed: terminator, inconsolata-fonts,
- Installed XFCE desktop as per K Thorne: yum groupinstall "Xfce" -y
-
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Attachment 1: IMG_20190103_205158.jpg
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14458
|
Fri Feb 15 18:41:18 2019 |
rana | Update | VAC | Vac system is back up |
If the acromags lock up whenever there is an electrical spike, shouldn't we have them on UPS to smooth out these ripples? And wasn't the idea to have some handshake/watchdog system to avoid silently dying computers?
Quote: |
The problem encountered with the vac controls was indeed resolved via the recommendation I posted yesterday. The Acromags had gone into a protective state (likely caused by an electrical transient in one of the signals)
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14460
|
Fri Feb 15 19:50:09 2019 |
rana | Update | VAC | Vac system is back up |
The acromags are on the UPS. I suspect the transient came in on one of the signal lines. Chub tells me he unplugged one of the signal cables from the chassis around the time things died on Monday, although we couldn't reproduce the problem doing that again today.
In this situation it wasn't the software that died, but the acromag units themselves. I have an idea to detect future occurrences using a "blinker" signal. One acromag outputs a periodic signal which is directly sensed by another acromag. The can be implemented as another polling condition enforced by the interlock code.
Quote: |
If the acromags lock up whenever there is an electrical spike, shouldn't we have them on UPS to smooth out these ripples? And wasn't the idea to have some handshake/watchdog system to avoid silently dying computers?
Quote: |
The problem encountered with the vac controls was indeed resolved via the recommendation I posted yesterday. The Acromags had gone into a protective state (likely caused by an electrical transient in one of the signals)
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14464
|
Mon Feb 18 19:16:55 2019 |
rana | Summary | Computers | new laptop setup: ASIA |
The old IBM laptop (Asia) has died from a fan error after 7 years. WE have a new Lenovo 330 IdeaPad to replace it:
- to enter bios, the usual FN keys don't work. Power off laptop. Insert paperclip into small hole on laptop side with upside-down U symbol. Laptop powers up into BIOS setup.
- Insert SL 7.6 DVD into drive
- Change all settings from modern UEFI into Legacy support. Change Boot order to put CDROM first.
- Boot.
- Touchpad is not detected. Hookup mouse for setup.
- Delete windows partition.
- Setup wireless network according to (https://wiki-40m.ligo.caltech.edu/Network). Computer name = asia.martian.
- Set root password. Do not create user (we want to make the controls acct later using the command line so that we can set userID and groupID both to 1001).
- Begin install...lots of disk access noises for awhile...
Install done. Touchpad not recognized by linux - lots of forum posts about kernel patching...Arrgh! |
14465
|
Tue Feb 19 19:03:18 2019 |
rana | Update | Computers | Martian router -> WPA2 |
I have swapped our martian router's WiFi security over to WPA2 (AES) from the previous, less-secure, system. Creds are in the secrets-40-red. |
14494
|
Thu Mar 21 21:50:31 2019 |
rana | Update | VAC | Protection against AC power loss |
agreed - we need all pumps on UPS for their safety and also so that we can spin them down safely. Can you and Chub please find a suitable UPS?
Quote: |
However, I discovered that TP1---the pump that might be most damaged by a sudden power failure---is not on the UPS. It's plugged directly into a 240V outlet along the wall. This is because the current UPS doesn't have any 240V sockets. I'd recommend we get one that can handle all the turbo pumps.
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14525
|
Tue Apr 9 00:16:22 2019 |
rana | Update | ALS | EX Green PDH error monitor calibrated |
G=10 or G=100? |
14530
|
Wed Apr 10 16:58:54 2019 |
rana | Update | IOO | fiber MZ for NPRO freq noise measurements |
Can we get some panel mount FC/APC connectors and put them on a box? Then we could have the whole setup inside of a box that is filled with foam and sits outside the PSL hut.  |
14542
|
Mon Apr 15 18:13:23 2019 |
rana | Update | Computer Scripts / Programs | Automated suspension testing with susPython |
if this gonna be general for everybody, maybe it oughta be called IFOtest (like the last incarnation that was tried in Livingston) ?
: |
In anticipation of needing to test hundreds of suspension signals after the c1susaux upgrade, I've started developing a Python package to automate these tests: susPython
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then the SUS tests could just be some smaller set of measurements. Using the same code base, but different params. |
14543
|
Mon Apr 15 18:29:07 2019 |
rana | Summary | Computers | new laptop setup: ASIA - yum issues |
had trouble using YUM to update. This turned out to be a config problem with our Martian router, not the new laptop. Since I've changed the WiFi pwd awhile ago for the martian access for the CDS laptops, you'll have to enter that in order to use the laptops.
turned out to be some Access Control nonsense inside of the router. Even loggin in as admin with a cable gave some of the fields the greyed out color (had to hover over the link and then type the URL directly in the browser window). ASIA is now able to connect and use YUM + usual connections. Gautam and I have also moved the router a little to get easier view of its LED lights and not blockk its WiFi signal with the cable tray. We'll get a little shelf so that we can mount it ~1 foot off of the wall.
still, this seems like a bad laptop choice: the Lenovo Ideapad 330 will not have its touchpad supported by SL7 without compiling a new version of the kernel  |
14557
|
Fri Apr 19 15:13:38 2019 |
rana | Update | SUS | No consistent solution for output matrix |
let us have 3 by 4, nevermore
so that the number of columns is no less
and no more
than the number of rows
so that forevermore we live as 4 by 4
Quote: |
I'm struggling to think
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14559
|
Fri Apr 19 19:22:15 2019 |
rana | Update | SUS | Actuation matrix still not orthogonal |
If thy left hand troubles thee
then let the mirror show the right
for if it troubles enough to cut it off
it would not offend thy sight |
14597
|
Wed May 8 19:04:20 2019 |
rana | Update | PSL | PSL turned on again |
- Increased PSL HEPA Variac from 30 to 100% to get more airflow.
- All of the TEC setpoints seem cold to me, so I increased the laser crystal temperature to 30.6 C
- Adjusted the diode TEC setpoints individually to optimize the PMC REFL power (unlocked). DTEC A = 22.09 C, DTEC B = 21.04 C
- locked PMC at 1900 PT; let's see how long it lasts.
My hunch is that the TECs are working too hard and can't offload the heat onto the heat sinks. As the diode's degrade, more of the electrical power is converted to heat in the diodes rather than 808 nm photons. So hopefully the increased airflow will help.
I tried to increase the DTEC setpoints, but that seems to detune them too far from the laser absorption band, so that's not very efficient for us. IN any case, if we end up changin the laser temperature, we'll have to adjust the ALS lasers to match, and that will be annoying.
The office area was very cold and the HVAC air flow stronger than usual. I changed the setpoint on the thermostat near Steve's desk from 71 to 73F at 1830 today. |
14598
|
Wed May 8 22:11:46 2019 |
rana | Summary | Computers | new laptop setup: ASIA - yum issues |
- setup controls user using K Thorne LLO CDS offsite workstation instructions
- modified /etc/fstab ala pianosa to NFS mount disks
- set up symlinks as other workstations
- troubles with libsasl2 and libmetaio libraries as usual for SL7 - doing symlink tricks
- setup shared .bashrc
- now running 'yum install gds-all' to see if we need more local libraries to run GDS from the shared disks...
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14646
|
Mon Jun 3 16:40:48 2019 |
rana | Update | Cameras | Telescope |
no BMP files  |
14668
|
Thu Jun 13 14:28:46 2019 |
rana | Update | Cameras | GigE setup |
don't need to lock - make sure the 4 OSEMs are centered on the camera field just as we have for the arm cavity mirrors
Quote: |
I'm attaching a picture of the screen. I just positioned the enclosure by turning it a bit and I suppose we can see the mirror inside the vacuum now (the MC2 is still not locked).
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14701
|
Wed Jun 26 18:28:24 2019 |
rana | Update | IOO | PMC and IMC locked again, some MEDM maintenance |
a useful piece of code that we should ask one of this summer's SURFs to write:
- read in a BURT .req file which is usually used to make the autosnap / restore.
- change ALL of the values to some value (slightly different from its current value)
- restore it to its current value
this will solve the sticky slider problem and do it in a systematic way. We can run it from the command line: e.g. 'unsticky.py c1psl c1ioo c1lsc'
Quote: |
Aaron complained to me earlier that the PMC could not be locked. Turned out to be a classic sticky slider problem,
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14709
|
Sun Jun 30 19:47:09 2019 |
rana | Update | IOO | IMC WFS agenda |
we are thinking of doing a sprucing up of the input mode cleaner WFS (sensors + electronics + feedback loops)
- WFS Heads
- it has been known since ~2002 that the RF circuits in the heads oscillate.
- in the attached PDF you can see that 2 opamps (U3 & U4; MAX4106) are used to amplify the tank circuit made up of the photodiode capacitance and L6.
- due to poor PCB layout (the output of U4 runs close to the input of U3) the opamps oscillate if the if the Reed relay (RY2) is left open (not attenuating)
- we need to remove/disable the relay
- also remove U3 for each quadrant so that it has a fixed gain of (TBD) and a 50 Ohm output
- also check that all the resonances are tuned to 1f, 2f, & 3f respectively
- Demod boards
- DC quadrant readouts
- Whitening
- Noise budget of sensors, including electronics chain
- diagonalization of sensors / actuators
- Requirements -
- Optical Layout
- What does the future hold ?
- what is our preferred pin-for-pin replacement for the MAX4106/MAX4107? internet suggests AD9632. Anyone have any experience with it? The Rabbott uses LMH6642 in the aLIGO WFSs. It has a lower slew rate than 9632, but they both have the same distortion of ~ -60 dB for 29.5 MHz.
- the whole DC current readout is weird. Should have a load resistor and go into the + input of the opamp, so as to decouple it from the RF stuff. Also why such a fast part? Should have used a OP27 equivalent or LT1124.
- LEMO connectors for RF are bad. Wonder if we could remove them and put SMA panel mount on there.
- as usual, makes me feel like replacing with better heads...and downstream electronics...
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Attachment 1: WFS-Head.pdf
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14735
|
Mon Jul 8 21:42:39 2019 |
rana | Update | Cameras | Ghost image due to beamsplitter |
you have to use a BS with a larger wedge angle (5 arcmin ~ 1 mrad) so that the beams don't overlap on the camera |
14793
|
Sun Jul 21 20:23:35 2019 |
rana | Update | IOO | MC locked |
I found the MC2 face camera disabled(?) and the MC servo board input turned off. I turned the MC locking back on but I don't see any camera image yet. |
14794
|
Sun Jul 21 22:16:34 2019 |
rana | Update | General | rossa Xdisp bricked |
"bricked" is to mean that it has the functionality of a brick and can be tossed. But rossa seems to have just gotten some software config corruption. I spent a couple hours reinstalling SL7 today as per my previous elog notes and the X display seems to work as before.
i.e. it was fine with the default setup, except for the ole "X chrashes if the mouse goes to left side of screen". As before, I
- blacklisted the nouvaeu driver (which is used by default)
- download the NVIDIA driver as per the link
- run its installation from the no-X terminal
left side of screen is safe again
This time I installed SL7.6 and followed the K Thorne wiki. But its having trouble installing cds-root because it can't find root.
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14799
|
Mon Jul 22 21:04:40 2019 |
rana | Update | Computers | making rossa great again |
- copied over /etc/fstab lines from pianosa sothat the NFS mounts work correctly
- added symlinks so that the NFS dirs mount in the right dirs
- installed Opera browser
- symlink libsasl2.so.3 -> libsasl2.so.2 and now DTT runs and can get data now and in the past
- DTT can natively produce PDF so you don't have to take screen caps of your camera phone and make a chalk drawing of that anymore
- sitemap/MEDM is working
- after editing fonts.alias as detailed in Thorne wiki, I ran 'sudo xset fp rehash' to get MEDM to notice new fonts. MEDM Scalable fonts are back!!
- installed Grace and now dataviewer works
- ndscope not running: yum install ndscope breaks because it can't find a couple of python34 packages

- tested that AWGGUI also runs and puts in real sine waves
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Attachment 1: seis.pdf
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14818
|
Tue Jul 30 20:11:12 2019 |
rana | Summary | IMC | IMC ASC: thoughts and hopes |
One of the biggest challenges in LIGO is reducing the alignment control noise. If you haven't worked on it for at least a few years, it probably seems like a trivial problem. But all versions of LIGO since 2001 have been limited by ASC noise below ~50 Hz.
I think the 40m IMC is a good testbed for us to try a few approaches towards mitigating this noise in LIGO. The following is a list of steps to take to get there:
- Using step responses and TF measurements, characterize the full existing system: SISO loop shapes, cross-couplings, and how diagnonal is the input and output matrices of the WFS. In principle, since we have 2 WFS in reflection and 1 DC QPD in the MC2 transmission, we should have full sensing of all angular DoFs.
- Check the correct operation of the WFS heads and the whole RF chain. We want the gains in the system to be such that either the shot noise or the RF electronics noise of the head is the limiting broadband noise in the system.
- Balancing the gains and phases of the demodulated signals is tricky, because we have no good reference. Should we use the JenneAM laser or the PSL beam?
- Estimate the coupling from the angular feedback signal to the IMC length noise using (1) sine wave injections for linear coupling, and (2) broadband noise for nonlinear coupling.
- We think the bilinear noise is due to the beam spot motion modulating the angle to length coupling as sensed by the laser beam. If this is true, we can increase the low frequency gain to minimize the beam spot motion (is this true?).
- By sinusoidally driving the mirror angles we can measure the instantaneous beam spot positions. We can then derive the matrix required to convert from our angular sensors (WFS + QPD) into beam spot motion. We should modify our IMC-WFS real-time model to give us DAQ channels which are beam spot estimators.
- Build a simulation of an IMC which has WFS, QPD, shot noise, and seismic noise.
- Use our optimal linear-feedback design tools to make Angular loops which minimize the bilinear noise coupling.
- Build a nonlinear controller (neural networks: dense + CNN) that outperforms the linear one by estimating the beam spot motion continuously and driving the cavity length to cancel the angle-to-length noise.
I think that steps 1-6 are well within our existing experience, but we should do it anyway so as to reduce the IMC beam motion at low frequencies, and also to reduce the 10-100 Hz frequency noise as seen by the rest of the interferometer.
Steps 7-8 are medium hard, but we can get some help from the CSWG in tackling it.
Step is pretty tough, but I would like to try it and also get some help from MLWG and CSWG to address it. |
14847
|
Fri Aug 16 04:24:03 2019 |
rana | Update | ALS | ALS sensing noise due to IMC |
What about just use high gain feedback to MC2 below 20 Hz for the IMC lock? That would reduce the excess if this theory is correct. |
14859
|
Thu Sep 5 20:30:43 2019 |
rana | HowTo | CDS | WFS discussion, restarting CDS |
via Polish chat, GV tells us to RTFE |
14864
|
Fri Sep 6 18:08:29 2019 |
rana | Update | Computers | Alarm noise from smart-ups machine under workstation? |
please no one touch the UPS: last time it destroyed ROSSA. Please ask Chub to order the replacement batteries so we can do this in a controlled way (fully shutting down ALL workstations first). Last time we wasted 8 hours on ROSSA rebuilding.
Quote: |
There was an alarm sound from the Smart-UPS 2200 sitting under the workstation. I see that the 'replace battery' light is red, and this elog tells me that these batteries are replaced every ~1-4 years; the last replacement was march 2016. Holding down the 'test' button for 2-3 seconds results in the alarm sound and does not clear the replace battery indicator.
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14878
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Mon Sep 16 05:08:04 2019 |
rana | Update | IOO | WFS loop measurements |
not need to use DTT. I'm attaching some half-finished notebooks that give the gist.
- Download the data with NDS2
- Downsample the data for ease of use.
- save the data as hdf5 for easy loading later.
- demodulate the data at the specified frequencies.
That's it! Now you have the complex, single frequency TFs. Next you invert the matrix. |
Attachment 1: LSCsensingMatrix.ipynb
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{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Get some ASC data - Calculate Sensing Matrix \n",
"### also make the radar plots"
]
},
... 327 more lines ...
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Attachment 2: ASCsensingMatrix.ipynb
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{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Get some ASC data - Calculate Sensing Matrix \n",
"### also make the radar plots"
]
},
... 325 more lines ...
|
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Mon Sep 23 10:49:34 2019 |
rana | Update | CDS | c1iscaux testing |
- I'd say permanently enable AA and AI. There's no reason to turn these off for usual channels. We can always undo one switch later if we want to use aliasing to sample a high frequency signal (ala SoCal).
- The PD output should ~20 nV/rHz into the mixer, so that's ~7 nV into the whitening filter. We need 60 dB to be above the ADC noise.
- I've forgotten what the current config is, but in iLIGO we hacked in a fixed whtiening on the Lt1128 input amp to the WF board so that the lock acquisition could be a little easier (better SNR). On Ch1, that's replacing R60 with a RC network. We want to make sure that the lock acq transients are not saturating the ADC, but can maybe put in a 40:200 stage.
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Wed Oct 2 20:45:18 2019 |
rana | Update | Computers | rossa revival |
Formatted and re-installing OS on rossa for the 3rd or 4th time this year. I suggest that whoever is installing software and adjusting video settings please stop.
If you feel you need to tinker deeply, use ottavia or zita and then be prepared to show up and fix it.
While I was moving the UPS around, the network lights went out for Rossa, so I may have damaged the network interface or cable. Debugging continues. |
14928
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Thu Oct 3 11:01:18 2019 |
rana | Update | LSC | (PR)FPMI locking |
wonder if its possible to do variable finesse locking
Gabriele mentioned that Virgo used arm trans PDH for this, but I guess we could possibly use POX/POY to start and bring in the PRM with 50% MICH trans |
14931
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Thu Oct 3 14:32:37 2019 |
rana | Update | General | Make the Jenne-laser setup fiber-coupled |
I'm curious to see if we really need the 1611, or if we can calibrate the diode laser vs. the 1611 one time and then just use that calibration to get the absolute cal for the DUT. |
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Thu Oct 3 21:50:22 2019 |
rana | Update | Computers | rossa revival |
Got the network to work again just by unplugging the power cord and letting it sit for awhile. But corrupted OS by trying to install Nvidia drivers.
https://www.advancedclustering.com/act_kb/installing-nvidia-drivers-rhel-centos-7/ |
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Tue Oct 8 16:54:56 2019 |
rana | Update | IOO | IMC locking not working after this work |
I think this offset setting thing is not so good. People do this every few years, but putting offsets in servos means that you cannot maintain a stable alignment when there are changes in the laser power, PMC trans, etc. The better thing is to do the centering of the WFS spots with the unlcoked beam after the control offsets have been offloaded to the suspensions. |
14959
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Wed Oct 9 12:15:05 2019 |
rana | Update | Electronics | WFS head RF measurements |
It would be good if you and Shruti can look at how to change the parameters in Zero so as to do a fit to the measured data. Usually, in scipy.optimize we give it a function with some changeable params, so maybe there's a way to pass params to a zero object in that way. I think Ian and Anchal are doing something similar to their FSS Pockel's cell simulator. |