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New entries since:Wed Dec 31 16:00:00 1969
    Reply  Tue May 3 13:18:47 2022, JC, Update, VAC, RGA Pump Down 

Jordan, Tega, JC

Issue has been resolved. Breaker on RP1 was tripped so the RP1 button was reporting ON, but was not actually on which continuously tripped the V6 interlock. Breaker was reset, RP1 and RP3 turned on. The V6 was opened to rough out the RGA volume. Once, pressure was at ~100mtorr, V4 was opened to pump the RGA with TP2. V6 was closed and RP1/3 were turned off.

RGA is pumping down and will take scans next week to determine if a bakeout is needed

Quote:

Jordan and I, in order to start pumpig down the RGA Volume, we began by opening V7 and VM. Afterwards, we started RP1 and RP3. After this, the pressure in the line between RP1, RP3, and V6 dropped to 3.4 mTorr. Next, we tried to open V6, although an error message popped up. We haven't been able to erase it since. But we were able to turn on TP2 with V4 closed. The pressure in that line is reporting 1.4 mTorr.

 

PRP on the sitemap is giving off an incorrect pressure for the line between RP1, RP3, and V6. This is verified by the pressure by the control screen and the physical controller as well. 

 

Entry  Fri May 20 12:42:23 2022, Tega, Update, VAC, Door installation on the end stations 

[JC, Tega, Chub]

Today we installed the 200 lbs doors on the end station chambers.

    Reply  Tue May 24 10:37:09 2022, Tega, Update, VAC, added FRG channels to slow channel ini file 

[Vacuum gauge sensors]

Paco informed me that the FRG sensor EPICS channels are not available on dataviewer, so I added them to slow channels ini file (/opt/rtcds/caltech/c1/chans/daq/C0EDCU.ini). I also commented out the old CC1, CC2, CC3 and CC4 gauges. A service restart is required for them to become available but this cannot be done right now because it would adversely affect the progress of the upgrade work. So this would be done at a later date.

Quote:

git repo - https://git.ligo.org/40m/vac

Finally incorporated the FRGs into the main modbusIOC service and everything seems to be working fine. I have also removed the old sensors (CC1,CC2,CC3,CC4,PTP1,IG1) from the serial client list and their corresponding EPICS channels. Furthermore, the interlock service python script has been updated so that all occurrence of old sensors (turns out to be only CC1) were replaced by their corresponding new FRG sensor (FRG1) and a redundnacy was also enacted for P1a where the interlock condition is replicated with P1a being replaced with FRG1 because they both sense the main volume pressure.

 

Entry  Tue May 24 11:04:53 2022, JC, Update, VAC, Beginning Pumpdown PUMPDOWN-2022-05-24_16-57-59.pngC1VAC_Screenshot_2022-05-24_16-59-27.png

[JC, Jordan, Paco, Chub]

We began with the pumpdown this morning. We started with the annulus volume and proceeded by using the following:

1. Isolate the RGA Volume by closing of valves VM3 and V7.

2. Opened valves VASE, VASV, VABSSCT, VABS, VABSSCO, VAEV, and VAEE, in that order.

3. Open VA6 to allow P3, FRG3, and PAN to equalize.

4. Turn on RP1 and RP3, rough out annulus volume, once <1 torr turn on TP3. Close V6. Open V5 to pump the annulus volume with TP3.

5. Re route pumping from RP1 and RP3 to the main volume by opening V3 and slowly opening RV1.

6. After ~3.5 hours the pressure in the arms was <500mtorr on both FRG1 and P1a. Turn on TP1 and wait to reach full speed 560 Hz

7. Open V1 with RV2 barely open. The pressure diff between P1a and P2/FRG2 needs to be below 1 torr. This took a couple attempts with the manual valve in different positions. The interlocks were tripped for this reason. Repeat step 7 until the manual gate valve was in a position that throttled pumping enough to maintain the <1 torr differential.

8. Slowly open the manual gate valve over the course of ~ 1 hour. Once the manual gate valve fully opened, pressure in the arms was <1mtorr.

9. V7 was closed, leaving only TP2 to back TP1, while TP3 was used to continue pumping the annuli. Left in that configuration overnight (see attached)

 

We did have to replace gauge PAN becuase it was reading a signal error. In addition, we found the cable is a bit sketchy and has a sharp bend. The signal comes in and out when the cable is fiddled with.

Entry  Wed Jun 8 16:03:12 2022, Koji, Update, VAC, Power Outage 220608: Vacuum Recovery Screenshot_2022-06-08_16-43-13.png

=== Observation ===

  • TP1/2/3 failed. AUX RP did not survive the power outage (of course)

=== Initial Recovery of TP2/TP3 ===

  • Stopped TP1/2/3
  • Restored RP AUX at the wall breaker module
  • Restarted TP2/3

=== Rough pumping down ===

  • Found RP1/RP3 left connected (unusual)
  • Turned on RP1 and RP3
  • Opened V6 and V7 for roughing of the pump spool. Now 0.3 torr for P2/P3/PA* (annuli) - ready to open V4 and V5 to backup TP1 by TP2 and TP3. Waiting for TP2/3 to be accelerated

=== Towards main volume pumping ===

  • TP2 accelerated and opened V4 (This caused V6 to close). RP1 and RP3 stopped.
  • TP3 hasitated to spin up. Stopped for now.
  • TP1 needed to be reset to clear the displacement errors. Once the errors were cleared, TP1 was restarted (acclerating).
  • TP1 at normal speed. Opened V1 (main volume pumping started)
     
  • Disconnected RP1/RP3 line.
     
  • TP3 was restarted and is now stable at 55k RPM (indicated as soft spin / low speed). Pushed "Stand By On" and "then "Stand By OFF". This makes the TP3 back to "NORMAL". Switched to "Stand By On".
  • TP2 was also switched to "Stand By On".

Now the main volume and the annuli are pumped down TP1 and TP2/TP3 with RP AUX backing.

The attachment is the pressure glitch for the main volume.

 

    Reply  Wed Jun 15 07:26:35 2022, JC, Update, VAC, Beginning Pumpdown 

[Jordan, JC]

Jordan and I went in to retore the Vacuum System back to it's original state before the power loss on June 8, 2022. The process went smoothly as we first closed V7 and opened VM3 (in that order).

The RP1/3 line did not have the KF blank installed. That was added and the RP flex line was capped off.

Quote:

[JC, Jordan, Paco, Chub]

We began with the pumpdown this morning. We started with the annulus volume and proceeded by using the following:

1. Isolate the RGA Volume by closing of valves VM3 and V7.

2. Opened valves VASE, VASV, VABSSCT, VABS, VABSSCO, VAEV, and VAEE, in that order.

3. Open VA6 to allow P3, FRG3, and PAN to equalize.

4. Turn on RP1 and RP3, rough out annulus volume, once <1 torr turn on TP3. Close V6. Open V5 to pump the annulus volume with TP3.

5. Re route pumping from RP1 and RP3 to the main volume by opening V3 and slowly opening RV1.

6. After ~3.5 hours the pressure in the arms was <500mtorr on both FRG1 and P1a. Turn on TP1 and wait to reach full speed 560 Hz

7. Open V1 with RV2 barely open. The pressure diff between P1a and P2/FRG2 needs to be below 1 torr. This took a couple attempts with the manual valve in different positions. The interlocks were tripped for this reason. Repeat step 7 until the manual gate valve was in a position that throttled pumping enough to maintain the <1 torr differential.

8. Slowly open the manual gate valve over the course of ~ 1 hour. Once the manual gate valve fully opened, pressure in the arms was <1mtorr.

9. V7 was closed, leaving only TP2 to back TP1, while TP3 was used to continue pumping the annuli. Left in that configuration overnight (see attached)

 

We did have to replace gauge PAN becuase it was reading a signal error. In addition, we found the cable is a bit sketchy and has a sharp bend. The signal comes in and out when the cable is fiddled with.

 

Entry  Fri Jul 8 14:03:33 2022, JC, HowTo, VAC, Vacuum Preparation for Power Shutdown  Screen_Shot_2022-07-12_at_7.02.14_AM.png

[Koji, JC]

Koji and I have prepared the vacuum system for the power outage on Saturday.

  1. Closed V1 to isolate the main volume.
  2. Closed of VASE, VASV, VABSSCI,VABS, VABSSCO, VAEV, and VAEE.
  3. Closed V6, then close VM3 to isolate RGA
  4. Turn off TP1 (You must check the RPMs on the TP1 Turbo Controller Module)
  5. Close V5
  6. Turn off TP3 (There is no way to check the RPMs, so be patient)
  7. Close V4 (System State changes to 'All pneumatic valves are closed)
  8. Turn off TP2 (There is no way to check the RPMs, so be patient)
  9. Close Vacuum Valves (on TP2 and TP3) which connect to the AUX Pump.
  10. Turn of AUX Pump with the breaker switch wall plug.

From here, we shutdown electronics.

  1. Run /sbin/shutdown -h now on c1vac to shut the host down.
  2. Manually turn off power to electronic modules on the rack.
    • GP316a
    • GP316b
    • Vacuum Acromags
    • PTP3
    • PTP2
    • TP1
    • TP2 (Unplugged)
    • TP3 (Unplugged)

 

Entry  Mon Jul 11 15:26:12 2022, JC, HowTo, VAC, Startup after Power Outage 

[Koji, Jc]

Koji and I began starting that Vacuum system up.

  1. Reverse order step 2 of shutting down electronics. Anthing after, turn on manually.
  2. If C1vac does not come back, then restart by holding the reset button.
  3. Open VA6
  4. Open VASE, VASV,VABSSCI, VABS, VABSSCO, VAEV, and VAEE
  5. Open V7
  6. Check P3 and P2, if they are at high pressure, approx. 1 Torr range, then you must use the roughing pumps.
  7. Connect Rotary pump tube. (Manually)
  8. Turn on AUX Pump
  9. Manually open TP2 and TP3 valves.
  10. Turn on TP2 and TP3, when the pumps finish startup, turn off Standby to bring to nominal speed.
  11. Turn on RP1 and RP3
  12. Open V6
  13. Once P3 reaches <<1 Torr, close V6 to isolate the Roughing pumps.
  14. When TP2 and TP3 are at nominal speed, open V5 and V4.
  15. Now TP1 is well backed, turn on TP1.
  16. When TP1 is at nominal speed, Open V1.
    Reply  Mon Jul 11 17:25:43 2022, Tega, Update, VAC, fixed obsolete reference bug in serial_XGS600 service 

Koji noticed that the FRG sensors were not updating due to reference to an obsolete modbusIOC_XGS service, which was used temporarily to test the operation of the serial XGS sensor readout to EPICS. The information in this service was later moved into modbusIOC.service but the dependence on the modbusIOC_XGS.service was not removed from the serial_XGS600.service. This did not present any issue before the shutdown, probably bcos the obsolete service was already loaded but after the restart of c1vac, the obsolete service file modbusIOC_XGS.service was no longer available. This resulted in  serial_XGS600.service throwing a failure to load error for the missing obsolete modbusIOC_XGS service. The fix involved replacing two references to 'modbusIOC_XGS' with 'modbusIOC' in  /opt/target/services/serial_XGS600.service.

I also noticed that the date logged in the commit message was Oct 2010 and that I could not do a push from c1vac due to an error in resolving git.ligo.org. I was able to push the commit from my laptop git repo but was unable to do a pull on c1vac to keep it synced with the remote repo.

    Reply  Mon Jul 11 17:41:52 2022, Koji, HowTo, VAC, Startup after Power Outage Screen_Shot_2022-07-11_at_18.13.00.png

- Once the FRG gauge readings are back (see next elog by Tega), I could open V1 to pump down the main vacuum manifold.
- TP2/TP3 were brought back to stand-by mode (slower spinning)
- V7 was closed to separate the annuli side and TP1

During the vacuum recovery, I saw TPs were automatically turned on as soon as the backing pumps were engaged. I could not figure out what caused this automation.

Also, I saw some gate valve states changed while I was not touching them. e.g. V7 was close / VM3 was open / etc
I really had no idea what/who was handling these.

As of ~18:00 local, the main volume pressure is ~2e-5 torr and ready to open the PSL shutter.

Entry  Fri Feb 11 16:43:09 2011, steve, Update, VIDEO, MC1 & 3 video monitor P1070415.JPG

I set up video monitoring of MC1 and MC3

Entry  Thu Feb 17 13:20:06 2011, Suresh, Update, VIDEO, Some more labels 

[Larisa, Kiwamu, Steve and Suresh]

 

  We continued the labeling of video cables. All exiting cables which are going to be used used in the new scheme have been labeled.

We also labeled the cables running from the video mux to the TV monitors in the computer room. Some of these will be removed or reallocated.

We will continue next Wednesday (after the meeting) and will lay cables that are most urgently required. 

 i

Entry  Wed Feb 23 16:56:17 2011, Larisa Thorne, Update, VIDEO, Cable laying...continued 

Having finished labeling the existing cables to match their new names, we (Steve, Kiwamu and Larisa) moved on to start laying new cables and labeling them according to the list.

 

Newly laid cables include: ETMXT (235'), ETMX (235'), POP (110') and MC2 (105').  All were checked by connecting a camera to a monitor and checking the clarity of the resulting image. Note that these cables were only laid, so they are not plugged in.

 

The MC2 cable needs to be ~10' longer; it won't reach to where it's supposed to. It is currently still in its place. 

The three other cables were all a lot longer than necessary.

    Reply  Wed Mar 9 16:07:42 2011, kiwamu, Update, VIDEO, cable session 

[Koji, Steve, Suresh, Kiwamu]

The following video cables have been newly laid down :

  - MC1F/MC3F (65 ft.)

  - PMCR (100 ft.)

  - PSL spare (100 ft.)

  - PSL1  (100 ft.)

  - PSL2  (100 ft.)

 

Entry  Wed Mar 30 17:01:08 2011, Larisa Thorne, Update, VIDEO, Cable laying...continued 

[Steve, Suresh, Kiwamu, Larisa]

 

Only the PRM/BS cable was laid today.

In one of the previous updates on cable laying, it was noted that the MC2 cable needed an additional 10' and the MC2T needed an additional 15' to reach their destinations.  We cut and put BNC ends on 10' and 15' cables and connected them to the original cables in order to make them long enough.

 

This concludes the laying of new cables. Suresh is currently working on the QUADs...

    Reply  Thu Mar 31 08:31:44 2011, Suresh, Update, VIDEO, Cable laying...continued P1070489.JPGP1070494.JPG

The video work has crossed a milestone.    

Kiwamu and Steve have shifted the three quads from the control room to the Video MUX rack (1Y1) and have wired them to the MUX.

The monitors in the control room have been repositioned and renumbered.  They are now connected directly to the MUX. 

Please see the new cable list for the input and output channels on the MUX.

As of today, all cables according the new plan are in place.  Their status   indicated on the wiki page above is not verified .  Please ignore that column for now, we will be updating that soon.

I shifted the MC1F/MC3F camera and the MC2F cameras onto the new cables.  Also connected the monitors at the BS chamber and end of the X arm to their respective cables.  I have removed the RG58B BNC (black) cables running from MC2 to BS and from ETMXF to the top of the Flow Bench. 

Some of the old video cables are still in place but are not used.   We might consider removing them to clear up the clutter. 

Some of the video cables in use are orange and if the lab's  cable color code is to be enforced these will have to be replaced with blue ones..

Some of the cables in use running from the MUX to the monitor in the control room are the white 50 Ohm variety.  There are also black RG59 Cables running the same way ( we have surplus cables in that path)  and we have to use those instead of the white ones. 

There are a number of tasks remaining:

a)  The inputs from the various existing cameras have to be verified. 

b) There are quite a few cameras which are yet to be installed.

c) The Outputs may not not be connected to their monitors.  That the monitors may still be connected to an old cable which is not connected to the MUX.  The new cable should be lying around close by.  So if you see a blank monitor please connect it to its new cable. 

d) The status column on the wiki page has to be updated.

e) Some of the currently in place may need to be replaced and some need to be removed.  We need to discuss our priorities and come up with a plan for that.

After checking everything we can certify that the video cabling system is complete.

I would like Joon Ho to take care of this verification+documenting process and declaring that the job is complete. 

 

Steve attached these two pictures.

Entry  Thu Apr 7 13:12:23 2011, Koji, HowTo, VIDEO, Video switching tip 

Long time ago, I looked at the manual of the video switcher.
http://media.extron.com/download/files/userman/Plus_Ultra_MAV_C.pdf
Here is the summary. This will be the basic of the more sophisticated switching program which may have GUI.

In principle, you can manually control the matrix via telnet. At the console machines, you can connect to the matrix using telnet

telnet 192.168.113.92

This opens TCP/IP port 23 of the specified machine. You will receive some messages.
Then type some command like:
--------------------

  • 1*2!       (connect input#1 to output#2)
  • 1,           (save the current setting into preset1)
  • 1.           (restore the setting from preset1)

--------------------

Basicaly that's all. There are many other features but I don't think we need them.

We can create a simple program with any of the language as any of the language has the capability of the TCP/IP connection.
e.g. C, Perl, Python. Tcl/Tk
Any of them are fine.

Now what we have to think about is how to implement the interface in the epics screen (or whatever).
It needs some investigation how the people is thinking as the ideal interface.
But, first of all, you should make the above three operations available as a simple UNIX command like:

videoswitch -i 192.168.113.92 1 2
videoswitch -i 192.168.113.92 -store 1
videoswitch -i 192.168.113.92 -recall 1
(There is no such command yet. These are showing what it should be!)

This can be done by a single day work and our life will be much better.

    Reply  Fri Apr 15 02:30:24 2011, Koji, HowTo, VIDEO, Video switching tip 

I have made a small python script to handle the video matrix.

It is too far from the perfection, but I release it as it is already useful in some extent.

The script is in the /cvs/cds/rtcds/caltech/c1/scripts/general directory.

usage:

videoswitch.py in_ch_name out_ch_name

in_ch_name is one of the followings

MC2F, IFOPO, OMCR, FI, AS_Spare, ITMYF, ITMXF, ETMYF, ETMXF,
PMCR, RCR, RCT, PSL_Spare, PMCT, ETMXT, MC2T, POP, IMCR, REFL,
MC1F, SRMF, AS, ETMYT, PRM, OMCT, Quad1, Quad2, Quad3

out_ch_name is one of the followings

Mon1, Mon2, Mon3, Mon4, Mon5, Mon6, Mon7,
ETMY, MC1, PSL1, PSL2, ETMX, MC2, CRT9,CRT10,Projector,
Quad1_1, Quad1_2, Quad1_3, Quad1_4,
Quad2_1, Quad2_2, Quad2_3, Quad2_4,

Quad3_1, Quad3_2, Quad3_3, Quad3_4

Entry  Wed Apr 20 20:42:55 2011, kiwamu, Update, VIDEO, today's video session DSC_2931_ss.jpgDSC_2938_ss.jpg

[Steve / Suresh / Kiwamu]

90 % of unused video cables have been removed.

Still a couple of video cables are floating around the video MUX. They will be removed in the next week's session.

DSC_2931_ss.jpg

DSC_2938_ss.jpg

 

Entry  Thu Aug 18 22:24:08 2011, jamie, Omnistructure, VIDEO, Updated 'videoswitch' script 

I have updated the 'videoswitch' program that controls the video MUX.  It now includes the ability to query the video mux for the channel mapping:

controls@pianosa:~ 0$ /opt/rtcds/caltech/c1/scripts/general/videoswitch -h
Usage:
videoswitch [options] [OUT]      List current output/input mapping [for OUT]
videoswitch [options] OUT IN     Set output OUT to be input IN

Options:
  -h, --help            show this help message and exit
  -i, --inputs          List input channels and exit
  -o, --outputs         List output channels and exit
  -l, --list            List all input and output channels and exit
  -H HOST, --host=HOST  IP address/Host name
controls@pianosa:~ 0$

Entry  Thu Jul 19 02:14:37 2012, Jenne, Update, VIDEO, Made a video gui 

I learned a little bit of python scripting while looking at the videoswitch script, and I made a video medm screen. 

Each monitor has a dropdown menu for all the common cameras we use (medm only lets you put a limited # of lines on a dropdown menu...when we want to add things like OMCR or RCT, we'll need to add another dropdown set)

Each monitor also has a readback to tell you what is on the TV.  So far, the quads only say "QUAD#", not what the 4 components are. 

I put a set of epics inputs in the PEM model, under a subsystem with top-names VID to represent the different monitors.  The readbacks on the video screen look at these, with the names corresponding to the numbers listed in the videoswitch script.  The videoswitch script now does an ezcawrite to these epics inputs so that even if you change the monitors via command line, the screen stays updated.

For example, since MC2F's camera is plugged in to Input #1 of the video matrix, if you type "./videoswitch MON1 MC2F", the script will write a "1" to the channel "C1:VID-MON1", and the screen will show "MC2F" in the Mon1 cartoon.

This required a quick recompile of the PEM model, but not the framebuilder since these were just epics channels.

There is also a dropdown menu for "Presets", which right now only include my 2 arm locking settings.

All of the dropdowns just call an iteration of the videoswitch script.

Entry  Tue Jul 24 18:33:12 2012, Yaakov, Update, VIDEO, Centering the MCR camera 

Jenne and I centered the MCR camera on the AP table.

We moved the camera as far as it could go on its mount without shifting its screws, and adjusted the optic that the camera looks at for the rest of the way.

    Reply  Wed Jul 25 11:41:00 2012, Yaakov, Update, VIDEO, Centering the MCR camera 

Quote:

Jenne and I centered the MCR camera on the AP table.

We moved the camera as far as it could go on its mount without shifting its screws, and adjusted the optic that the camera looks at for the rest of the way.

 The spot was still off center on the quad display in the control room, so I re-recentered it today.

Entry  Wed Nov 28 19:02:41 2007, Andrey, Bureaucracy, WIKI-40M Update, New WIKI-40M page describing Matlab Suspension Modeling 

I created the WIKI-40m page with some details about my today's talk on the 40-m lab meeting.

The address is:

http://lhocds.ligo-wa.caltech.edu:8000/40m/Modeling_of_suspensions

(or you can go to the main page, http://lhocds.ligo-wa.caltech.edu:8000/40m/ , and click on the link "Modeling of suspensions").

The WIKI-40m page describes my transfer functions and contains the pdf-file of my presentation.
Entry  Wed Jan 2 11:38:56 2008, tobin, Summary, WIKI-40M Update, wiki spam 
Our wiki keeps getting spammed. It turns out that you can upload attachments without a password, which is a bug. I'll ask David Barker whether there's a fix for this.
Entry  Tue Aug 25 03:30:23 2009, Yoichi, Summary, WIKI-40M Update, Green lock and phase noise PhaseNoise.png
While Koji and I were discussing about the green laser lock, we wondered if the common motion of the cavity mirrors,
which won't be suppressed by the green laser servo, will cause any problem to the locking.

Since the common motion of the cavity mirrors is equivalent to the change of the path length from the laser to the
input mirror, it will show up as a phase noise in the error signal.
Unfortunately, since we inject the green laser from the end mirror, this phase noise has opposite sign for the
PSL and the green laser.

I calculated the magnitude of the phase noise using an extremely rough estimate of the common motion of the mirrors.
It is explained in the 40m wiki.
http://lhocds.ligo-wa.caltech.edu:8000/40m/Upgrade_09/GreenLock

The result plot is attached.
(Probably the seismic noise I used is an over estimate.)
Entry  Wed Oct 21 11:41:29 2009, Zach, Update, WIKI-40M Update, PSL Table Diagram wiki entry 

 I made a wiki entry for the PSL table diagram under the PSL directory on the 40mHomePage. I tried to use the ImageLink macro to use a resized (smaller) version of the diagram as a link to the full image, which it is designed to do if there is no target given, but it didn't seem to work. Instead, I had to create a second page that had the full-sized diagram, and I used ImageLink with a smaller version to link to that page.

The inventory that is shown is clearly incomplete. Part of this is due to the fact that many labels were either missing or impossible to read without touching stuff. For those components with labels missing, I tried to infer what they were to the best of my knowledge, but I wasn't able to for all of them. In true wiki spirit, everyone is encouraged to fill in any additional information they might have on these components. 

    Reply  Wed Oct 21 13:07:54 2009, Koji, Update, WIKI-40M Update, PSL Table Diagram wiki entry 

http://lhocds.ligo-wa.caltech.edu:8000/40m/PSL_Table_Diagram

Thanks. I love this. Could you also put the original file that is editable for future modification by anyone?

Quote:

 I made a wiki entry for the PSL table diagram under the PSL directory on the 40mHomePage. I tried to use the ImageLink macro to use a resized (smaller) version of the diagram as a link to the full image, which it is designed to do if there is no target given, but it didn't seem to work. Instead, I had to create a second page that had the full-sized diagram, and I used ImageLink with a smaller version to link to that page.

The inventory that is shown is clearly incomplete. Part of this is due to the fact that many labels were either missing or impossible to read without touching stuff. For those components with labels missing, I tried to infer what they were to the best of my knowledge, but I wasn't able to for all of them. In true wiki spirit, everyone is encouraged to fill in any additional information they might have on these components. 

 

Entry  Wed Oct 21 15:07:45 2009, Alberto, Update, WIKI-40M Update, Photodiodes' configuration for the Upgrade 

I uploaded on the Wiki (here) the results of an inventory over our current PDs, a list of the new ones that we're going to need for the new control scheme.

Entry  Thu Oct 22 15:44:16 2009, Zach, Update, WIKI-40M Update, MOPA diagram 

 I have updated the PSL Diagram wiki page to include MOPA. As with the PSL diagram, clicking the photo on the main page takes you to a larger image. The inventory is pretty meager as I didn't have time to sit and read labels (if indeed there are any). I will look through the documentation at the 40m to see if there is a record of what is there. Again, if you know something, please amend the list!!

http://lhocds.ligo-wa.caltech.edu:8000/40m/PSL_Table_Diagram

    Reply  Thu Oct 22 15:49:29 2009, Zach, Update, WIKI-40M Update, PSL Table Diagram wiki entry 

Quote:

http://lhocds.ligo-wa.caltech.edu:8000/40m/PSL_Table_Diagram

Thanks. I love this. Could you also put the original file that is editable for future modification by anyone?

Quote:

 I made a wiki entry for the PSL table diagram under the PSL directory on the 40mHomePage. I tried to use the ImageLink macro to use a resized (smaller) version of the diagram as a link to the full image, which it is designed to do if there is no target given, but it didn't seem to work. Instead, I had to create a second page that had the full-sized diagram, and I used ImageLink with a smaller version to link to that page.

The inventory that is shown is clearly incomplete. Part of this is due to the fact that many labels were either missing or impossible to read without touching stuff. For those components with labels missing, I tried to infer what they were to the best of my knowledge, but I wasn't able to for all of them. In true wiki spirit, everyone is encouraged to fill in any additional information they might have on these components. 

 

 Do you mean the diagram or the inventory? The diagrams are online as attachments (small versions on the main "PSL Table Diagram" page and large versions on the linked pages). The inventory is easily editable on the wiki itself. It's just rendered in table form using the CSV parse utility for "comma-separeted values" (though you actually need to use semicolons, for reasons unknown).

    Reply  Thu Oct 22 21:58:26 2009, Koji, Update, WIKI-40M Update, PSL Table Diagram wiki entry 

Diagram. I don't want to say PNG is an editable format for this purpose...
You have the PPT, PDF or any drawing format to create this diagram.

Quote:

http://lhocds.ligo-wa.caltech.edu:8000/40m/PSL_Table_Diagram

Thanks. I love this. Could you also put the original file that is editable for future modification by anyone?

 Do you mean the diagram or the inventory? The diagrams are online as attachments (small versions on the main "PSL Table Diagram" page and large versions on the linked pages). The inventory is easily editable on the wiki itself. It's just rendered in table form using the CSV parse utility for "comma-separeted values" (though you actually need to use semicolons, for reasons unknown).

 

    Reply  Thu Oct 22 23:14:54 2009, Zach, Update, WIKI-40M Update, PSL Table Diagram wiki entry 

Quote:

Diagram. I don't want to say PNG is an editable format for this purpose...
You have the PPT, PDF or any drawing format to create this diagram.

Quote:

http://lhocds.ligo-wa.caltech.edu:8000/40m/PSL_Table_Diagram

Thanks. I love this. Could you also put the original file that is editable for future modification by anyone?

 Do you mean the diagram or the inventory? The diagrams are online as attachments (small versions on the main "PSL Table Diagram" page and large versions on the linked pages). The inventory is easily editable on the wiki itself. It's just rendered in table form using the CSV parse utility for "comma-separeted values" (though you actually need to use semicolons, for reasons unknown).

 

 

Good news and bad news. For the MOPA diagram, which I did recently, I have GIMP file with separate layers for the background image, ray traces, and labels. Unfortunately, I didn't realize that this was the best way to do it until I had done most of the ray tracing for the main diagram, so, although I have that file in GIMP as well, only the labels are on a separate layer. If this is a major issue I can do the tracing again. The other thing is that the original files are quite large: 17.3 MB for the MOPA, and 64.1(!) MB for the main diagram. Let me know what you think.

Entry  Sat Jun 12 19:43:19 2010, Alberto, Update, WIKI-40M Update, IFO modeling Wiki Page updated 

Today I started writing the IFO modeling wiki page.

The idea is to make it a reference place where to share our modeling tools for the 40m.

Entry  Wed Jun 23 11:25:14 2010, Katharine and Sharmila, Update, WIKI-40M Update, Maglev 

Weekly update


Lab work

We compared the magnetic field strength for 4 magnets in the original setup. The standard deviation was 3.15 G which corresponds to a variation of 2.4%. We had encountered difficulties with the stability of the Gaussmeter. The tip of the Gaussmeter was unsteady and wobbling which led to huge variations for a small change in distance. We stabilized the meter by taping it to a pencil and securing it with wire ties to an aluminum block. We then used translation stages to find the point of maximum field strength for each magnet, which allowed us much more stable readings.

Readings

We are reading and learning about feedback control systems. 

Modelling

Learning to model in Comsol. Our goals for the 1X1 model include incorporating the gravitational force in the measurements and find the distance for which attraction is the strongest, and experimenting with the mesh density and boundary conditions of the domain.

Meetings/seminars

Attended many meetings, including:
Laser safety training
SURF safety training
LIGO seminars
Journal club
LIGO experimental group meeting

Entry  Wed Jun 23 11:31:12 2010, nancy, Update, WIKI-40M Update, Weekly Update 

This week I attended a whole lot of orientations, lectures, and meetings related to SURF. Done with general and laser safety training.

read Nergis' thesis for, and other material on WFS.

got confused with how the sidebands and shifted carrier frequencies are chosen for the Interferometer, read initial chapters of Regehr's thesis for teh same.

Made a plan for proceeding with the WFS work through discussions with Koji.

Understood the MC cavity and drew a diagram for it and the sensors.

Did Calculations for Electric field amplitudes inside and outside the MC cavity.

Saw the hardware of the WFS and QPD inside, and their routes to computers. Figured out which computer shows up the conditioned data from teh sensors.

Tried calculating the cavity axis for MC using geometry and ray tracing. Too complicated to be done manually.

Read some material (mainly Seigman) for physics of calculating the eigen-axis of the MC cavity with mirrors mis-aligned. Will calculate that using simulations, using the ABCD matrices approach.

Made a simple feedback simulink model yesterday to learn simulink. Made it run/compile. Saw the behaviour thru time signals at different points.

in the night, Made a simulink model of the sensor-mirror thing, with transfer functions for everything as dummy TFs. Compiles, shows signals in time. Remaining part is to put in real/near-real TFs in the model.

Entry  Wed Jun 30 11:39:20 2010, nancy, Update, WIKI-40M Update, Weekly Update 

Wednesday Morning E-log :

 

Most of the time through this week, i was working towards making the simulink model work.

It involved learning simulink functions better, and also improving on the knowledge of control theory in general, and control theory of our system.

1. Thusrday : found tfs for the feedback loop. and tried many different filters and gains to stabilize the system (using the transient response of the system). - not through

2. Friday : decided to use error response and nullify the steady state error instead of looking at convergence of output. tried many other filter functions for that.

Rana then showed me his files for WFS.

3. Sunday - played with rana's files, learnt how to club simluink with matlab, and also about how to plot tfs using bode plots in matlab.

4. Monday : Read about state-space models, and also how to linearize in matlab. done with the latter, but the former still needs deeper understanding.

read ray-optics theory to calculate the geometric sensing matrix.

It first requires to calculate the eigen mode of the cavity with tilted mirrors. this eigen mode is needed to be found out using ray-optics transfer matrices for the optics involved  . figured out  matrices for the tilted plane mirrors, and am working on computing the same for MC2.

5. Tuesday : went to Universal Studios , Hollywood :P

6. Wednesday (today) : Writing the report to be submitted to SFP.

Entry  Wed Jun 30 12:13:39 2010, Sharmila, Katharine, Update, WIKI-40M Update, weekly update 

Weekly Project Update:

We are studying Haixing's circuit diagram for the quadrant maglev control circuit.  We have analyzed several of the sub-circuits and plotted transfer functions for these in MatLab.  To check the circuit, we will compare the calculated transfer functions with those obtained from the HP control systems analyzer.

To learn how to use the control systems analyzer, we are reading App Note 243 as well as an online manual (477 pages in the first volume).  We are beginning with a simple test circuit, and are comparing its measured frequencyresponse with calculated transfer functions.  We currently have obtained a response graph beginning at 100 Hz (which we have not yet figured out how to print), and we are planning to investigate behavior at lower frequencies.

We also have been continuing our reading on control systems after a failed attempt at magnetic levitation. 

Entry  Wed Jul 7 11:23:08 2010, Sharmila, Katharine, Update, WIKI-40M Update,  

Weekly Update:

Last Weds-Thurs, we wrote and edited our progress reports.

Tuesday (and Weds morning):  Continued circuit analysis of Haixing's circuit and plotting transfer functions (almost have one for entire circuit).  Hooked up OSEM and circuit to power supply, but the LED didn't appear to light up in IR.  Now we are going to hook the OSEM directly to the power supply, sans circuit, to see if the problem is with the circuit or OSEM.

Entry  Wed Jul 7 11:35:59 2010, Gopal, Update, WIKI-40M Update, 6.30.10 - 7.7.10 Weekly Update  

Summary of this Week's Activities:

6/30: 2nd and 3rd drafts of Progress Report

7/1: 4th draft and final drafts of Progress Report; submitted to SFP

7/5: Began working through busbar COMSOL example

7/6: LIGO meeting and lecture; meeting with Koji and Steve to find drawing of stacks; read through Giaime's thesis, Chapter 2 as well as two other relevant papers.

7/7: Continued working on busbar in COMSOL; should finish this as well as get good headway on stack design by the end of the day.

Entry  Wed Jul 14 11:32:36 2010, Sharmila, Katharine, Update, WIKI-40M Update,  

Weekly update:

We correctly connected our circuit to power source to verify that it was functional and that our LED in the shadow sensor turned on.  It did, but we also noticed a funky signal from the LED driver.  We continued to attempt 1x1 levitation, but determined that the temporary flag we were using out of convenience (a long, thin cylindrical magnet) was weakly attracted to residually magnetized OSEM components.  We then switched to an aluminum screw as our flag.

We resoldered and applied heat shrink to the wires connecting our coil to the BNC terminal, since they were falling apart.

We sat down with Rana and removed circuit components in the LED drive part by part to determine what was tripping up the circuit.  We determined a rogue capacitor to be at fault and removed it from the circuit.

We used a spectrum analyzer to measure the frequency response of our circuit (see details in last elog).  We are currently making a Simulink block diagram so we can check the stability of our setup, but are temporarily set back because our plotted calculation of the transfer function clearly doesn't match the measured one.

Entry  Wed Jul 14 13:03:04 2010, Gopal , Update, WIKI-40M Update, 7.8.10 - 7.14.10 Weekly Update 

Summary of this Week's Activities:

Wed. 7/7: COMSOL Busbar tutorials; began stack design; began base; Viton rubber research

Thurs. 7/8: Completed Viton rubber research; updated materials; finished designing the base layer

Fri. 7/9: Research model coupling papers; extensive eLog entry about base design and troubleshooting

Sun. 7/11: Played around with Busbar to find first eigenfrequency; continued crashing COMSOL

Mon. 7/12: Intrusions in COMSOL eLog tutorial entry; research eigenfrequency analysis; successfully got first eigenmode of rectangular bar

Tues. 7/13: Updated Poisson ratio of Viton and subsequently succeeded in running eigenfrequency tests on base stack layer. Systematic Perturbation Tests were documented in the most recent elog entry. Discussed results with Rana and decided this didn't make sense. Analytical study required.

Wed. 7/14: Went over to machine shop to experimentally extrapolate spring constant of Viton. Calculations to be done in the afternoon.

Entry  Wed Jul 21 11:57:59 2010, Gopal, Update, WIKI-40M Update, 7.14.10-7.21.10 Weekly Update 

Summary of this week's activities:

7/14: Analytical calculation of Viton spring constant; updated Viton values in models; experimental confirmation of COMSOL eigenfrequencies (single stack layer)

7/15: Extensions to 2-, 3-, and 4-layer stack legs. Eigenfrequency characterizations performed for each level. Meshing issues with 4-layer stack prevented completion.

7/19: Debugged the 4-layer stack. Turned out to be a boundary condition issue because of non-sequential work-plane definitions. Successful characterization of single-leg eigenfrequencies.

7/20: Prototype three-legged stack completed, but dimensions are incorrect. Read Sievers paper for details of triple-legged stack. Sorted through many stack design binders in efforts to distinguish IOC/OOC, BSC/ITMX/ITMY, MC1/MC3, and MC2 dimensions.

7/21: Researched frequency domain analysis testing in COMSOL. Attempting to first find transfer function of a single-layer stack --> currently running into some run-time errors that will need some more debugging in the afternoon.

Entry  Wed Jul 21 12:03:14 2010, Katharine, Sharmila, Update, WIKI-40M Update, weekly update 

This past week, we levitated our small cylindrical magnet (with the flag made from heat shrink).  Though the levitated magnet didn't appear very jittery to the eye, we looked at the PD current on the scope and could see oscillations that corresponded to the flag hitting the sides of the OSEM.  The oscillations were more pronounced as we gently hit/vibrated the lab bench, and by pounding on the bench Rana knocked the levitated magnet completely out of the setup.  So, we're currently working on building a new, stabler mount.  The biggest challenge here is fixing the OSEM in place, but we're experimenting with different optics pieces to see which is the most stable for our purposes.   Jenne taught us how to make through holes using the drill press so we can add slats of aluminum to adjust the height of the OSEM mount.  We also plan to fix some heavy plates to the bottom of our system to decrease its vibration frequency.

We also calculated the transfer function of our circuit, which seems to match the measured frequency response to within a small factor.  We're playing with Rana's Simulink models and are currently modeling our own system to determine what gains we would expect to use and get a better understanding of our circuit.


Once our system is successfully mounted stably, we plan to experimentally observe the effects of changing the gain and integrator by looking at time series measurements of the PD current, as well as using the spectrum analyzer to compare the frequency response of our system at different gain settings.

Entry  Wed Jul 28 12:09:06 2010, Sharmila,Katharine, Update, WIKI-40M Update, Maglev Picture_1.png

We have modeled our maglev setup in simulink but we have a few corrections to make since the system goes into undamped oscillations for an impulse in the input.

We have made a stable mount for the system and started to work on the 2X2 system using this mount. We have to figure out a way to match the magnets with the gain. We have attached the simulink block.

Picture_1.png

Entry  Wed Jul 28 12:31:00 2010, Gopal, Update, WIKI-40M Update, 7.21.10-7.28.10 Weekly Update 

Summary of this week's activities:

7/21: Frequency Domain Analysis of rectangular bar; discussed with Koji how to convert complex eigenfrequencies into phase factors.

7/23: Created Wiki page about FDA; Journal Club

7/26: Recreated Stack_1234.mph due to boundary value issues; FDA for 1,2,3,4,5 Hz

7/27: Discovered MC2 logbooks for later design; ran the complete x-translational FDA for Stack_1234.mph

7/28: Finished y-translational FDA (posted previously); "Tapered Cantilever" COMSOL tutorial for gravity-load analysis.

Entry  Wed Aug 4 20:58:22 2010, Gopal, Update, WIKI-40M Update, 7.28.10 - 8.4.10 Weekly Update 

Summary of this week's activities:

7/28:    Finished Y-Translational 4-Stack Analysis

"Tapered Cantilever" COMSOL tutorial

Tried (and failed) isolating gravity from oscillation

7/29:    Developed tilt/rotation load combinations for torsional inputs and showed these to work in the model

Tried using Normal Vector mode on top plate to obtain output tilts; worked for the rectangular bar, but not for the full stack

Talked to Jan about a 1st-order alternative to gravity - requires Weak Form (only found in COMSOL 3.5 right now)

Began Z-Translational 4-Stack Analysis -- Ran Overnight

7/30:    Progress Report 1st Draft

Completed Z-Translational 4-Stack Analysis

8/1:      Progress Report 2nd Draft

8/2:      Progress Report 3rd Draft

Submitted Progress Report

8/3:      Finalized Eigenfrequency Analysis for MC1/MC3 Stack

24 Physical Eigenmodes plotted and recorded, as expected

Should be good enough for the final report --> focus on transfer function analysis for the remainder of the SURF

8/4:      Prescribed Displacement Tests on Simple Rectangular Block --> shown to better produce displacement-displacement transfer functions

X-to-X Transfer Function seems much better when plotted

Should now be able to do the Displacement portion of Transfer Function Analysis on MC1/MC3 for Translational Modes

(I apologize that this update is a little late)

Entry  Wed Aug 11 11:51:45 2010, Gopal , Update, WIKI-40M Update, 8.5.10 - 8.11.10 Weekly Update 

Summary of this Week's Activities:

Thursday, August 5:

X-Displacement Transfer Function Measurement

JPL Tour

Friday, August 6:

Y-Displacement Transfer Function Measurement

Z-Displacement Transfer Function Measurement

Monday, August 9:

Worked on COMSOL/MatLab Interface --> problems may be due to older version

Discussed with Koji options for calling our COMSOL sales representative

Jan and I decided that there is in fact something wrong with the installations on both my Mac and Kallo

Reinstalled on both machines, but the problem was not solved

Jan said we'd go see Larry tomorrow

Tuesday, August 10:

Attempted to figure out Time-Dependent Modal Analysis --> don't think it's what we need

Began reading the LiveLink for MatLab documentation --> even the directions in this produced issues

Discovered "Prescribed acceleration" option for gravity:

A test with it on the simplest stack eliminated the unwanted oscillation, which I guess is a partial success...

Trying the same thing with Koji on a simple pendulum, however, didn't produce the expected increase in resonant frequency

(Jan was unable to see Larry today, but we're meeting on Wednesday instead).

Wednesday, August 11 (morning):

Some background research on multiple-layer stack theory

Began working on presentations

 

 

 

Entry  Thu Jan 12 21:22:16 2012, Leo Singer, Configuration, WIKI-40M Update, Unable to create Wiki page 

 I can't create a new page on the 40m wiki.  The page that I was trying to create is

http://blue.ligo-wa.caltech.edu:8000/40m/Stewart

I get this message when I try to save the new page:

Page could not get locked. Unexpected error (errno=13).

    Reply  Thu Jan 12 23:13:42 2012, Koji, Configuration, WIKI-40M Update, Unable to create Wiki page 

Quote:

 I can't create a new page on the 40m wiki.  The page that I was trying to create is

http://blue.ligo-wa.caltech.edu:8000/40m/Stewart

I get this message when I try to save the new page:

Page could not get locked. Unexpected error (errno=13).

This address for wiki is obsolete. Recently it was switched to https://wiki-40m.ligo.caltech.edu/
Jamie is working on automatic redirection from the old wiki to the new place.

The new one uses albert.einstein authentication.

 

ELOG V3.1.3-