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  13858   Thu May 17 13:51:35 2018 Jon RichardsonConfigurationElectronicsDocumentation & Schematics for AUX-PSL PLL

[Jon, Gautam]

Attached is supporting documentation for the AUX-PSL PLL electronics installed in the lower PSL shelf, as referenced in #13845.

Some initial loop measurements by Gautam and Koji (#13848) compare the performance of the LB1005 vs. an SR560 as the controller, and find the LB1005 to be advantageous (a higher UGF and phase margin). I have some additional measurements which I'll post separately.

Loop Design

Pickoffs of the AUX and PSL beams are routed onto a broadband-sensitive New Focus 1811 PD. The AUX laser temperature is tuned to place the optical beat note of the two fields near 50 MHz. The RF beat note is sensed by the AC-coupled PD channel, amplified, and mixed-down with a 50 MHz RF source to obtain a DC error signal. The down-converted term is isolated via a 1.9-MHz low-pass filter in parallel with a 50 Ohm resistor and fed into a Newport LB1005 proportional-integral (PI) servo controller. Controller settings are documented in the below schematic. The resulting control signal is fed back into the fast PZT actuator input of the AUX laser.

Schematic diagram of the PLL.

 

 

 

 

 

 

 

 

 

 

Hardware Photos

Optical layout on the PSL table.

 

PLL electronics installed in the lower PSL shelf.

 

Close-up view of the phase detector electronics.

 

Slow temp. (left) and fast PZT signals into the AUX controller.

 

AUX-PSL beat note locked at 50 MHz offset, from the control room.

 

  13867   Fri May 18 19:59:55 2018 Jon RichardsonConfigurationElectronicsAUX-PSL PLL Characterization Measurements

Below is analysis of measurements I had taken of the AUX-PSL PLL using an SR560 as the servo controller (1 Hz single-pole low-pass, gain varied 100-500). The resulting transfer function is in good agreement with that found by Gautam and Koji (#13848). The optimal gain is found to be 200, which places the UGF at 15 kHz with a 45 deg phase margin.

For now I have reverted the PLL to use the SR560 instead of the LB1005. The issue with the LB1005 is that the TTL input for remote control only "freezes" the integrator, but does not actually reset it. This is fine if the lock is disabled in a controlled way (i.e., via the medm interface). However, if the lock is lost uncontrollably, the integrator is stuck in a garbage state that prevents re-locking. The only way to reset this integrator is to manually flip a switch on the controller box (no remote reset). Rana suggests we might be able to find a workaround using a remote-controlled relay before the controller.

  13876   Tue May 22 10:14:39 2018 Jon RichardsonConfigurationElectronicsDocumentation & Schematics for AUX-PSL PLL

 

Quote:

[Jon, Gautam]

Attached is supporting documentation for the AUX-PSL PLL electronics installed in the lower PSL shelf, as referenced in #13845.

Some initial loop measurements by Gautam and Koji (#13848) compare the performance of the LB1005 vs. an SR560 as the controller, and find the LB1005 to be advantageous (a higher UGF and phase margin). I have some additional measurements which I'll post separately.

Loop Design

Pickoffs of the AUX and PSL beams are routed onto a broadband-sensitive New Focus 1811 PD. The AUX laser temperature is tuned to place the optical beat note of the two fields near 50 MHz. The RF beat note is sensed by the AC-coupled PD channel, amplified, and mixed-down with a 50 MHz RF source to obtain a DC error signal. The down-converted term is isolated via a 1.9-MHz low-pass filter in parallel with a 50 Ohm resistor and fed into a Newport LB1005 proportional-integral (PI) servo controller. Controller settings are documented in the below schematic. The resulting control signal is fed back into the fast PZT actuator input of the AUX laser.

Schematic diagram of the PLL.

 

 

 

 

 

 

 

 

 

 

Hardware Photos

Optical layout on the PSL table.

 

PLL electronics installed in the lower PSL shelf.

 

Close-up view of the phase detector electronics.

 

Slow temp. (left) and fast PZT signals into the AUX controller.

 

AUX-PSL beat note locked at 50 MHz offset, from the control room.

 

 

  13891   Fri May 25 13:06:33 2018 Jon RichardsonConfigurationElectronicsImproved Measurements of AUX-PSL PLL

Attached are gain-variation measurements of the final, in situ AUX-to-PSL phase-locked loop (PLL).

Attachment 1: Figure of open-loop transfer function

Attachment 2: Raw network analyzer data

The figure shows the open-loop transfer function measured at several gain settings of the LB1005 PI servo controller. The shaded regions denote the 1-sigma sample variance inferred from 10 sweeps per gain setting. This analysis supercedes previous posts as it reflects the final loop architecture, which was slightly modified (now has a 90 dB low-frequency gain limit) as a workaround to make the LB1005 remotely operable. The measurements are also extended from 100 kHz to 1 MHz to resolve the PZT resonances of the AUX laser.

Conclusions:

  • Gain variation confirms response linearity.
  • At least two PZT resonances above the UGF are not far below unity (150 kHz and 500 kHz).
  • Recommend to lower the proportional gain by 3 dB. This will place the UGF at 30 kHz with 55 degrees of phase.
  13893   Fri May 25 14:55:33 2018 Jon RichardsonUpdateCamerasStatus of GigE Camera Software Fixes

There is an effort to switch to an all-digital system for the GigE camera feeds similar to the one running at LLO, which uses Joe Betzwieser's custom SnapPy package to interface with the cameras in Python and aggregate their feeds into a fancy GUI. Joe's code is a SWIG-wrapping of the commercial camera-driver API, Pylon, from Basler. The wrapping allows the low-level camera driver methods to be called from within Python, and their feeds are forwarded to a gstreamer stream also initiated from within Python. The problem is that his wrapping (and the underlying Pylon software itself) is only runnable on an older version of Ubuntu. Efforts to run his software on newer distributions at the 40m have failed.

I'm working on a fix to essentially rewrite his high-level SnapPy code (generators of GUIs, etc.) to use the newest version of Pylon (pylon5) to interface at a low level with the cameras. I discovered that since the last attempt to digitize the camera system, Basler has released their own official version of a Python wrapping for Pylon on github (PyPylon).

Progress so far:

  • I've installed from source the newest version of Pylon, pylon5.0.12 on the SL7 machine (rossa). I chose that machine because LIGO is migrating to Scientific Linux, but I think this will also work for any distribution.
  • I've installed from source the the newest, official Python wrapping of the Basler Pylon software, pypylon.
  • I've tested the pypylon package and confirmed it can run our cameras.

The next and final step is to modify Joe's SnapPy package to import pypylon instead of his custom wrapping of an older version of the camera software, and update all of the Pylon calls to use the new methods. I'll hopefully get back to this early next week.

  13914   Mon Jun 4 11:34:05 2018 Jon RichardsonUpdateCamerasUpdate on GigE Cameras

I spent a day trying to modify Joe B.'s LLO camera client-server code without ultimate success. His codes now runs without throwing any errors, but something inside the black-box handoff of his camera source code to gstreamer appears to be SILENTLY FAILING. Gautam suggested a call with Joe B., which I think is worth a try.

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).

It uses the same PyPylon API to interface with the GigE cameras as does Joe's code. However, it uses matplotlib instead of gstreamer to render the imaging. The matplotlib code is optimized for maximum refresh rate and I observed it to achieve ~5 Hz for a single video feed. However, this demo code does not set any custom cameras settings (it just initializes a camera with its defaults), so it's quite possible that the refresh rate is actually limited by, e.g., the camera exposure time.

Location of the code (on the shared network drive):

/opt/rtcds/caltech/c1/scripts/GigE/demo_with_mpl/stream_camera_to_mpl.py

This demo initializes a single GigE camera with its default settings and continuously streams its video feed in a pop-up window. It runs continuously until the window is closed. I installed PyPylon from source on the SL7 machine (rossa) and have only tested it on that machine. I believe it should work on all our versions of Linux, but if not, run the camera software on rossa for now.

Usage:

From within the above directory, the code is executed as 

$python stream_camera_to_mpl.py [Camera IP address]

with a single argument specifying the IP address of the desired camera. At the time I tested, there was only one GigE camera on our network, at 192.168.113.152.

  13898   Wed May 30 16:12:30 2018 Jonathan HanksSummaryCDSLooking at c1oaf issues

When c1oaf starts up there are 446 gain channels that should be set to 0.0 but which end up at 1.0.  An example channel is C1:OAF-ADAPT_CARM_ADPT_ACC1_GAIN.  The safe.snap file states that it should be set to 0.  After model start up it is at 1.0.

We ran some tests, including modifying the safe.snap to make sure it was reading the snap file we were expecting.  For this I set the setpoint to 0.5.  After restart of the model we saw that the setpoint went to 0.5 but the epics value remained at 1.0.  I then set the snap file back to its original setting.  I ran the epics sequencer by hand in a gdb session and verified that the sequencer was setting the field to 0.  I also built a custom sequencer that would catch writes by the sdf system to the channel.  I only saw one write, the initial write that pushed a 0.  I have reverted my changes to the sequencer.

The gain channel can be caput to the correct value and it is not pushed back to 1.0.  So there does not appear to be a process actively pushing the value to 1.0.  On Rolfs sugestion we ran the sequencer w/o the kernel object loaded, and saw the same behavior.

This will take some thought.

  629   Thu Jul 3 12:36:05 2008 JonhSummarySUSETMY watchdog
ETMY watchdog was tripped. I turned it off and re-enabled the outputs.
  3976   Tue Nov 23 11:32:03 2010 JoonhoSummaryElectronicsRF distribution unit.

The last time(Friday) I made an arrangement for RF distribution unit.

I am making RF distribution unit for RF upgrade which is designed by Alberto.

 

To reduce a noise from loose connection,

I tried to make the number of hard connect as much as possible while reducing the number of connection via wire.

This is why I put splitters right next to the front pannel so that the connection between pannel plugs and splitters could be made of hard joints.

I attached the arrangement that I made on the last Friday.

 

Next time, I will drill the teflon(the supporting plate) for assembly.

Any suggestion would be really appreciated.

  4139   Tue Jan 11 21:08:19 2011 JoonhoSummaryCamerasCCD cables upgrade plan.

Today I have made the CCD Cable Upgrade Plan for improvement of sysmtem.

I have ~60 VIDEO cables to be worked for upgrades so I would like to ask all of your favor in helping me of replacing cables.

 

1. Background

Currently, VIDEO system is not working as we desire.

About 20 cables are of impedance of 50 or 52 ohm which is not matched with the whole VIDEO system.

Moreover, some cameras and monitors are out of connection.

 

2. What I have worked so far.

I have checked impedance of all cables so I figured out which cables can be used or should be replaced.

I measured cables' pathes along the side tray so that we can share which cable is installed along which path.

I have made almost of cables necessary for VIDEO system upgrades but no label is attached so far.

 

3. Upgrade plan (More details are shown in attached file)

 

0 : Cable for output ch#2 and input ch#16 is not available for now
1 : First, we need to work on the existing cables. 
1A : Check the label on the both ends and replace to the new label if necessary
1B : We need to move the existing cable's channel only for those currently connected to In #26 (from #26 to #25)
2 : Second, we need to implement new cables into the system
2A : Make two cable's label and attach those on the both ends
2B : Disconnect existing cables at the channel assigned for new cables and remove the cables from the tray also
2C : Move 4 quads into the cabinet containing VIDEO MUX
2D : Implement the new cable into the system along the path described and connect the cables to the assgined channel and camera or monitor

 

 

4. This is a kind of  a first draft of the plan.

Any comment for the better plan is always welcome.

Moreover, replacing all the cables indicated in the files is of great amount of work.

I would like to ask all of your favors in helping me to replace the cables (from 1. to 2D. steps above).

 

  4328   Fri Feb 18 20:17:07 2011 JoonhoSummaryElectronicsIsolation of Voltage regulator

Today I was working on RF distribution box.

So far I almost finished to electronically isolate voltage regulators from the box wall by inserting mica sheet, sleeve, and washers.

 

The problem I found is the resistance between wall and the voltage regulator is order of M ohms

I checked my isolation (mica sheet and sleeve and washer) but there is no problem there.

But I found that the power switch is not completely isolated from the wall.( around 800 kohm)

and that the resistance between the regulator and the wall is smaller for the regulator closer to the power switch

and greater for the regulator less closer to it.

So I think we need to put washer or sleeve to isolate the powersitch electronically from the box wall.

Suresh or I will fix this problem

[ To Suresh, I can finish the isolation when I come tomorrow. Or you can proceed to finish isolation.]

  3655   Tue Oct 5 18:27:18 2010 Joonho LeeSummaryElectronicsCCD cable's impedence

Today I checked the CCD cables which is connected to the VIDEOMUX.

17 cables are type of RG59, 8 cables are type of RG58. I have not figured out the type of other cables(23 cables) yet.

The reason I am checking the cables is for replacing the cables with impedance of 50 or 52 ohm by those with impedance of 75 ohm.

After I figures out which cable has not proper impedance, I will make new cables and substitute them in order to match the impedance, which would lead to better VIDEO signal.

To check the impedance of each CCD cable, I went to the VIDEOMUX and looked for the label on the cable's surface.

Type of RG59 is designated to the cable of impedance 75ohm. I wrote down each cable's input or output channel number with observation(whether it is of type RG59 or not).

The result of observation is as follows.

Type channel number where it is connected to
Type 59 in#2, in#11, in#12, in#15, in#18, in#19, in#22, in#26, out#3, out#4, out#11, out#12, out#14, out#17, out#18, out#20, out#21
Type 58 in#17, in#23, in#24, in#25, out#2, out#5, out#7, out#19
unknown type others

 

For 23 cables that I have not figured out their type, cables are too entangled so it is limited to look for the label along each cable.

I will try to figure out more tomorrow. Any suggestion would be really appreciated.

  3694   Mon Oct 11 23:55:25 2010 Joonho LeeSummaryElectronicsCCD cables for output signal

Today I checked all the CCD cables which is connected output channels of the VIDEOMUX.

Among total 22 cables for output, 18 cables are type of RG59, 4 cables are type of RG58.

The reason I am checking the cables is for replacing the cables with impedance of 50 or 52 ohm by those with impedance of 75 ohm.

After I figures out which cable has not proper impedance, I will make new cables and substitute them in order to match the impedance, which would lead to better VIDEO signal.

 

Today, I labeled all cables connected to output channels of VIDEO MUX and disconnect all of them since last time it was hard to check every cable because of cables too entangled.

With thankful help by Yuta, I also checked which output channel is sending signal to which monitor while I was disconnecting cables.

Then I checked the types of all cables and existing label which might designate where each cable is connected to.

After I finished the check, I reconnected all cables into the output channel which each of cable was connected to before I disconnected.

 

4 cables out of 22 are type of RG58 so expected to be replace with cable of type RG59.

The result of observation is as follows. 

Ch#
where its signal is sent type
1 unknown 59
2 Monitor#2  58
3 Monitor#3 59
4 Monitor#4 59
5 Monitor#5 58
6 Monitor#6 59
7 Monitor#7 58
8 unknown / labeled as "PSL output monitor" 59
9 Monitor#9 59
10 Monitor#10 59
11 Monitor#11 59
12 Monitor#12 59
13 Unknown 59
14 Monitor#14 59
15 Monitor#15 59
16 unknown / labeled as "10" 59
17 unknown 59
18 unknown / labeled as "3B" 59
19 unknown / labeled as "MON6 IR19" 58
20 unknown 59
21 unknown 59
22 unknown 59

I could not figure out where 10 cables are sending their signals to. They are not connected to monitor turned on in control room

so I guess they are connected to monitors located inside the lab. I will check these unknown cables when I check the unknown input cables.

Next time, I will check out cables which is connected to input channels of VIDEIO MUX. Any suggestion would be really appreciated.

  3739   Mon Oct 18 22:11:32 2010 Joonho LeeSummaryElectronicsCCD cables for input signal

Today I checked all the CCD cables which is connected input channels of the VIDEOMUX.

Among total 25 cables for output, 12 cables are type of RG59, 4 cables are type of RG58, and 9 cables are of unknown type.

The reason I am checking the cables is for replacing the cables with impedance of 50 or 52 ohm by those with impedance of 75 ohm.

After I figures out which cable has not proper impedance, I will make new cables and substitute them in order to match the impedance, which would lead to better VIDEO signal.

 

Today, I check the cables in similar way as I did the last time.

I labeled all cables connected to input channels of VIDEO MUX and disconnect all of them since last time it was hard to check every cable because of cables too entangled.

Then I checked the types of all cables and existing label which might designate where each cable is connected to.

After I finished the check, I reconnected all cables into the input channel which each of cable was connected to before I disconnected.

 

4 cables out of 25 are type of RG58 so expected to be replace with cable of type RG59.

9 cables out of 25 are of unknown type. These nine cables are all orange-colored thick cables which do not have any label about the cable characteristic on the surface.

The result of observation is as follows.

Note that type 'TBD-1' is used for the orange colored cables because all of them look like the same type of cable.

 

Channel number where its signal is coming type
1 C1:IO-VIDEO 1 MC2 TBD-1
2 FI CAMERA 59
3 PSL OUTPUT CAMERA 59
4 BS  C:1O-VIDEO 4 TBD-1
5 MC1&3 C:1O-VIDEO 5 59
6 ITMX C:1O-VIDEO 6 TBD-1
7 C1:IO-VIDEO 7 ITMY TBD-1
8 C1:IO-VIDEO 8 ETMX TBD-1
9 C1:IO-VIDEO 9 ETMY TBD-1
10 No cable is connected
(spare channel)
 
11 C1:IO-VIDEO 11 RCR 59
12 C1:IO-VIDEO RCT 59
13 MCR VIDEO 59
14 C1:IO-VIDEO 14 PMCT 59
15 VIDEO 15 PSL IOO(OR IOC) 59
16 C1:IO-VIDEO 16 IMCT TBD-1
17 PSL CAMERA 58
18 C1:IO-VIDEO 18 IMCR 59
19 C1:IO-VIDEO 19 SPS 59
20 C1:IO-VIDEO 20 BSPO TBD-1
21 C1:IO-VIDEO 21 ITMXPO TBD-1
22 C1:IO-VIDEO 22 APS1 59
23 ETMX-T 58
24 ETMY-T 58
25 POY CCD VIDEO CH25 58
26 OMC-V 59

Today I could not figure out what impedance the TBD-1 type(unknown type) has.

Next time, I will check out the orange-colored cables' impedance directly and find where the unknown output signal is sent. Any suggestion would be really appreciated.

  3782   Tue Oct 26 01:53:21 2010 Joonho LeeUpdateElectronicsFuction Generator removed.

Today I worked on how to measure cable impedance directly.

In order to measure the impedance in RF range, I used a function generator which could generate 50MHz signal and was initially connected to the table on the right of the decks.

The reason I am checking the cables is for replacing the cables with impedance of 50 or 52 ohm by those with impedance of 75 ohm.

After I figures out which cable has not proper impedance, I will make new cables and substitute them in order to match the impedance, which would lead to better VIDEO signal.

 

To test the VIDEO cables, I need a function generator generating signal of frequency 50 MHz.

In the deck on the right of PSL table, there was only one such generator which was connected to the table on the right of the deck.

Therefore, I disconnected it from the cable and took it to the control room to use it because Rana said it was not used.

Then, I tired to find on how to measure the impedance of cable directly but I did not finish yet.

When I finished today works, I put the generator back to the deck but I did not connect to the previous cable which was initially connected to the generator.

 

Next time, I will finish the practical method of measuring the cable impedance then I will measure the cables with unknown impedance.

Any suggestion would be appreciated.

  3949   Thu Nov 18 16:42:29 2010 Joonho LeeConfigurationElectronicsQuad Video for PMCT, RCT, RCR fixed.

The far right monitor in the control room is now displaying IMCR, PMCT, RCR, RCT.

Please note that top left quad is displying PMCT even if the screen is labeled with PMCR.

 

Control room monitor #13 - #16 had been out of order since the last week.

(the monitor number is shown at : http://lhocds.ligo-wa.caltech.edu:8000/40m/Electronics/VideoMUX )

I found that the connections between camera and the cable to the VIDEO MUX were missing so I connected them.

Initially, PMCT camera was sending its signal to the small monitor on the PSL table.

I splitted the signal so that one signal is going to the small monitor and another is going to the VIDEO MUX.

The "PMCR" is shown on the screen #13 in the control room but it actually showing PMCT camera's signal.

 

This is a temporary VIDEO configuration. It will be upgraded as well when the whole VIDEO will be upgraded.

  3950   Thu Nov 18 17:42:20 2010 Joonho LeeSummaryElectronicsCCD cables.

I finished the direct measurement of cable impedances.

Moreover, I wrote the cable replacement plan.

The reason I am checking the cables is for replacing the cables with impedance of 50 or 52 ohm by those with impedance of 75 ohm.

After I figures out which cable has not proper impedance, I will make new cables and substitute them in order to match the impedance, which would lead to better VIDEO signal.

Moreover, as Koji suggested, the VIDEO system will be upgraded for better interface.

 

I measured the cable impedance by checking the reflection ratio at the point connected to the terminator with 50 ohm or 75 ohm.

The orange colored cables are measured to be 75ohm so we do not need to replace them.

Combining the list of cable types and the list of desired length,

I need to make total 37 cables and to remove 10 cables from the current connection.

Detailed plan is attached below.

I currently ordered additional cables and BNC plugs.

 

From now on, I will keep making CCD cables for VIDEO upgrade.

Then, with your helps, we will replace the CCD cables.

 

In my opinion, I will finish VIDEO upgrade by this year.

  4010   Fri Dec 3 15:56:50 2010 Joonho, Jenne.SummaryElectronicsRF distribution unit plan

The last time(Moonday) Jenne and I worked on the RF distribution unit's structure.

We are making RF distribution unit for RF upgrade which is designed by Alberto.

 

Rana, Koji, Jenne suggested a better design for RF Distribution unit.

So Jenne and I gathered information of parts and decided what parts will be used with specific numbers.

Specific circuit is shown in the attached picture.

 

Any suggestion would be really appreciated.

  15158   Mon Jan 27 14:01:01 2020 JordanConfigurationGeneralRepurposed Sorenson Power Supply

The 24 V Sorenson (2nd from bottom) in the small rack west of 1x2 was repurposed to 12V 600 mA, and was run to a terminal block on the north side of 1X1. Cables were routed underneath 1X1 and 1X2 to the terminal blocks. 12V was then routed to the PSL table and banana clip terminals were added.

  15203   Mon Feb 10 15:04:42 2020 JordanUpdateGeneralHDMI Routing for new tv

Ran HDMI to the new tv mounted on the north wall of control room.

  15204   Mon Feb 10 15:54:47 2020 JordanUpdatePSLCompleted Acromag Wiring

All spare channels on the PSL acromag chassis are connected with ~12in of spare wiring for future use.

  15205   Mon Feb 10 15:55:46 2020 JordanUpdatePSLPMCTRANSPD

[Gautam, Jordan]

Gautam showed me how the PMCTRANSPD signal was reading zero, and he suspected it might have to do with the acromag wiring. Disconnected the acromag box underneath the PSL table and checked the ADC wiring. Side note: When benchtesting the c1psl acromag chassis there was excess noise in the AI channels, and grounding the minus pin of the ADC channel eliminates the noise.

So I grounded the (-) pins on the ADC1 (192.168.113.122), which PMCTRANSPD is connected to and that seemed to fix the problem. As of right now PMCTRANSPD is reading ~.75 V.

See attached pictures

gautam: While this fix seems to have worked, I wonder why this became necessary only in the last month. Note that the problem was a noisy readback on the PMC transmission PD, which also made the FSS_RMTEMP channel noisy, leading me to suspect some kind of ground loop issue.

  15344   Fri May 22 10:14:47 2020 JordanUpdateGeneralNitrogen Replacement

I was in the lab for Clean and Bake activities and I replaced an empty N2 tank. Left tank is at 2600 psi right tank at ~1300 psi.

  15354   Tue May 26 10:04:54 2020 JordanUpdateGeneralN2 Replacement

Replaced empty N2 tank, left tank at ~2000 psi, right tank ~2600 psi.

  15375   Thu Jun 4 08:45:41 2020 JordanUpdateGeneralPresence at 40m

I will be at the 40m, in the Clean and bake lab today from ~9am to ~3pm.

  15378   Fri Jun 5 08:44:50 2020 JordanUpdateGeneralPresence at 40m

I will be at the 40m, in the Clean and bake lab today from ~9am to ~3pm.

  15385   Tue Jun 9 09:35:02 2020 JordanUpdateGeneralPresence at 40m

I will be in the Clean and Bake lab today from 9:30am to 4pm.

  15388   Wed Jun 10 14:00:33 2020 JordanUpdateGeneralPresence at 40m

I will be in the Clean and Bake lab from 10am to 4pm today. I will also replace an empty N2 cylinder.

  15390   Thu Jun 11 11:14:12 2020 JordanUpdateGeneralPresence at 40m

I will be in the Clean and Bake lab today from 11am to 4pm.

  15395   Fri Jun 12 11:40:14 2020 JordanUpdateGeneralPresence at 40m

I will be in the Clean and Bake lab today from 12pm to 4pm.

  15400   Tue Jun 16 08:58:11 2020 JordanUpdateGeneralPresence at 40m

I will be at the 40m today at 10am to deliver optics to Downs and to replace the TP2 controller.

  15403   Tue Jun 16 16:05:26 2020 JordanUpdateGeneralN2 Replacement

I replaced an empty N2 cylinder, there are now two empty tanks in the outside rack.

  15405   Thu Jun 18 09:46:03 2020 JordanUpdateGeneralPresence at 40m

I will be at the 40m today from 9:30am to 4pm.

  15409   Thu Jun 18 15:25:08 2020 JordanUpdateVACTP2 and TP3 Forepump removal

I removed the backing pumps for TP2 and TP3 today to test ultimate pressure and determine if they need a tip seal replacement. This was done with Jon backing me on Zoom. We closed off TP3 and powered down TP3 and the auxilliary pump, in order to remove the forepumps from the exhaust line.

  1. Close V1
  2. Close V5
  3. Turn off TP3
  4. Turn off aux dry pump (manually)
  5. Once the PTP3 foreline pressure has come up to atmosphere, you can disconnect the TP3 dry pump and cap the exhaust line with a KF blank.
  6. Restore the vac configuration in reverse order: dry pump ON, TP3 ON, open V5, open V1

Once pumps were removed I connected a Pirani gauge to the pump directly and pumped down, results as follows:

TP2 Forepump (Agilent IDP 7):

  • Ultimate Pressure: 123 mtorr
  • Hours: 10903

TP3 Forepump (Varian SH 110):

  • Ultimate pressure: ~70 torr
  • Hours: 60300

TP3 forepump defintely needs a new tip seal, and while the pressure on TP2 Forepump was good there was a significant amount of particulate that came out of the exhaust line, so a new tip seal might not be needed but it is recommeded.

  15411   Thu Jun 18 16:56:34 2020 JordanUpdateVACTP2 and TP3 Forepump removal
Quote:

I removed the backing pumps for TP2 and TP3 today to test ultimate pressure and determine if they need a tip seal replacement. This was done with Jon backing me on Zoom. We closed off TP3 and powered down TP3 and the auxilliary pump, in order to remove the forepumps from the exhaust line.

  1. Close V1
  2. Close V5
  3. Turn off TP3
  4. Turn off aux dry pump (manually)
  5. Once the PTP3 foreline pressure has come up to atmosphere, you can disconnect the TP3 dry pump and cap the exhaust line with a KF blank.
  6. Restore the vac configuration in reverse order: dry pump ON, TP3 ON, open V5, open V1

Once pumps were removed I connected a Pirani gauge to the pump directly and pumped down, results as follows:

TP2 Forepump (Agilent IDP 7):

  • Ultimate Pressure: 123 mtorr
  • Hours: 10903

TP3 Forepump (Varian SH 110):

  • Ultimate pressure: ~70 torr
  • Hours: 60300

TP3 forepump defintely needs a new tip seal, and while the pressure on TP2 Forepump was good there was a significant amount of particulate that came out of the exhaust line, so a new tip seal might not be needed but it is recommeded.

I agree with your assessment, Jordan.  If I'm not mistaken the scroll pump for TP2 is new; we had a very early failure with the last new scroll pump (the forepump for TP3) tip seals at just over 5000 hours.  Glad to see my replacement seals held up for over 60K hours. If this is the trend with these pumps, we can simply run them to  around 60000 hours and replace the seals at that time, rather than waiting for failure! - Chub

  15414   Fri Jun 19 08:47:10 2020 JordanUpdateGeneralPresence at 40m

I will be at the 40m today from 9am to 3pm.

  15417   Fri Jun 19 14:03:50 2020 JordanUpdateVACForepump Tip Seal Replacement

Tip Seals were replaced on the forepumps for TP2 and TP3, and both are ready to be installed back onto the forelines.

TP2 Forepump Ultimate Pressure: 180 mtorr

TP3 Forepump Ultimate Pressure: 120 mtorr

  15422   Mon Jun 22 13:16:38 2020 JordanUpdateGeneralPresence at 40m

I will be at the 40m today from 11am to 4pm.

  15426   Wed Jun 24 10:14:56 2020 JordanUpdateGeneralPresence at 40m

I will be in the Clean and Bake lab today from 10am to 4pm.

  15430   Thu Jun 25 11:09:01 2020 JordanUpdateGeneralPresence at 40m

I will be in the Clean and Bake lab from 11pm to 4pm

  15432   Fri Jun 26 11:00:52 2020 JordanUpdateGeneralPresence at 40m

I will be in the Clean and Bake lab today from 11am to 4pm.

  15437   Mon Jun 29 11:41:04 2020 JordanUpdateGeneralPresence at 40m

I will be in the Clean and Bake lab today from 11:30am to 4pm

  15441   Tue Jun 30 08:50:12 2020 JordanUpdateGeneralPresence at 40m

I will be in the clean and bake lab today from 9am to 4pm.

  15444   Wed Jul 1 08:51:52 2020 JordanUpdateGeneralPresence at 40m

I will be in the Clean and Bake lab from 9am to 4pm today.

  15448   Thu Jul 2 16:51:23 2020 JordanUpdateGeneralBathroom Science

As part of an ongoing effort to improve airflow in workspaces/bathrooms on campus, I have installed an air scrubber unit in each of the bathrooms at the 40m lab.

  15453   Mon Jul 6 08:48:15 2020 JordanUpdateGeneralPresence at 40m

I will be in the Clean and Bake lab today from 8:30am to 4pm

  15459   Wed Jul 8 08:51:35 2020 JordanUpdateGeneralPresence at 40m

I will be in the clean and bake lab today from 9am to 3pm.

  15461   Thu Jul 9 09:22:44 2020 JordanUpdateGeneralPresence at 40m

I will be in the Clean and Bake lab today from 9am to 3pm

  15467   Fri Jul 10 10:37:30 2020 JordanUpdateGeneralPresence at 40m

I will be in the Clean and Bake lab today from 9am to 4pm

  15478   Tue Jul 14 09:04:53 2020 JordanUpdateGeneralPresence at 40m

I will be in the Clean and Bake Lab today from 9am to 4pm.

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