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ID Date Author Type Category Subjectup
  8836   Fri Jul 12 12:51:13 2013 CharlesUpdateISSRMS Noise from PMC Transmission

I went out on the floor to look at the transmitted signal from the PMC to get a rough idea of the noise of the unstabilized laser. There was already a scope hooked up so I just used the measurement features to find the following:

Signal average = 875 mV.  Peak-to-Peak noise = 45 mV

Assuming the noise can be approximated as Gaussian noise, the heuristic for converting to RMS noise of the signal is RMS = Peak-to-Peak / 8 (or Peak-to-Peak / 6, I've used both...)

-> RMS Noise ~ 6.5 mV

When designing my filtering stages and RMS detection/triggering, I'll use relative RMS, i.e. 6 mV / 875 mV = 0.007, as a measure of unstabilized laser noise.

  8838   Fri Jul 12 13:15:43 2013 KojiUpdateISSRMS Noise from PMC Transmission

It would be better to measure the power spectrum density of the fluctuation.
The RMS does not tell enough information how the servo should be.
In deed, the power spctrum density gives you how much the RMS is in the entire or a specific frequency range.

  8839   Fri Jul 12 18:30:20 2013 CharlesUpdateISSRMS Noise from PMC Transmission

Quote:

It would be better to measure the power spectrum density of the fluctuation.
The RMS does not tell enough information how the servo should be.
In deed, the power spctrum density gives you how much the RMS is in the entire or a specific frequency range.

I wanted the RMS noise simply to establish a very rough estimate of thresholds on RMS detectors that will be part of my device. If you refer to elog 8830, I explain it there. Essentially, when the ISS is first engaged, only one of the 2 or 3 filter stages will be active. Internal RMS threshold detection serves to create a logic input to switch subsequent filters to their 'on' stage.

  8830   Thu Jul 11 13:52:51 2013 CharlesUpdateISSRMS threshold detection and triggering

There are essentially two major portions of the ISS I am designing. One system has the voltage reference, differential amplifier and filtering servo (schematic attached) while the other has a comparator circuit and a triggering mechanism. The first system amplifies an error signal obtained from the PD output and the voltage reference, which is then fed back through the AOM. I've done a lot of work designing/prototyping this first half and now I'm starting to design the second half.

The second system's main purpose is to maintain loop stability as the ISS is engaged. Let's assume a user has decided they want noise suppression. They would first close the ISS feedback loop and an error signal would pass through three unity-gain buffers, providing minimal noise reduction. The user can then send a signal to theTRIGGER 1 port to switch the first stage from its unity-gain position to its filtering position and reduce the intensity noise further. This signal will most likely be digital in origin. Alternatively, when the user first closes the ISS loop, the first stage can already be in its filtering position rather than necessitating two commands.

A test channel (not drawn in the included schematic) will monitor the RMS level of the incoming signal from the PD. This noisy AC signal will first be amplified and then passed through an RMS-to-DC converter. The resulting DC signal is used as a part of the triggering mechanism for later stages. Once the first stage has been switched manually, and the DC signal corresponding to RMS noise of the PD output drops below a certain threshold, stages 2 and 3 will be internally triggered with a short delay between them. Toward being able to detect this threshold, I have designed a simple comparator circuit with an LT1016. The circuit has a fairly low-level output when the input voltage is larger than the threshold (about 1.6 V for my simple prototype), but when the input passes below the threshold, the comparator puts out almost 4 V, a number limited by the supply voltage. The schematic is shown below.

Simple_Comparator_Circuit.png

The component V2 and the various voltage dividers serve to establish the reference/threshold voltage. Note that although the LT1016 is not powered in the schematic, it requires ±5 V (a max of 7 V). The above circuit was also prototyped on a breadboard and I characterized it with an oscilloscope. Using a CFG253, I made a low frequency (~0.3 Hz) triangle wave with an amplitude and DC offset such that it oscillates between 0 and 5 V. This was applied to the IN node in the above schematic. The input waveform and the circuit's response (voltage at the OUT node) are shown below. As expected, R2 serves to establish hysteresis. The comparator switches to 'high' output until the input drops below 1.6 V, and then it doesn't switch back to the 'low' output until the input goes up to ~3.4 V.

F0001TEK.JPG

This behavior is ideal for our application as we can detect when the DC signal from the RMS-to-DC converter drops below a certain level (i.e. the first stage that has been activated does some amount of filtering to lower RMS noise), and then we can trigger subsequent filter stages off of the comparators high-level output. 

This circuit could easily be used to drive the MAX333a switches shown in the first schematic attached. I believe the low-level output is not sufficient to switch the MAX333a although the ~4 V high-level output is quite sufficient. Regardless, these exact values (thresholds, outputs etc) will be determined after I have a better idea of the RMS noise of the laser without any intensity stabilization as well as a solid understanding of how the AD8436 RMS-to-DC converter works. This was simply a proof of concept for lower threshold detection using basic Schmitt trigger topology.

  11134   Wed Mar 11 19:15:03 2015 KojiSummaryLSCROUGH calibration of the darm spectrum during the full PRFPMI lock

I made very rough calibration of the DARM spectra before and after the transition for the second lock on Mar 8.

The cavity pole (expected to be 4.3kHz) was not compensated. Also the servo bump was not compensated.

[Error calibration]

While the DARM/CARM were controlled with ALS, the calibration of them are provided by the ALS phase tracker calibration.
i.e 1 degree = 19.23kHz

This means that the calibration factor is

DARM [deg] * 19.23e3 [Hz/deg] / c [m Hz] * lambda [m] * L_arm [m]
= DARM* 19.23e3/299792458*1064e-9*38.5 = 2.6e-9 *DARM [m]

[Feedback calibration]

Then, the feedback signal was calibrated by the suspension response (f=1Hz, Q=5)
so that the error and feedback signals can match at 100Hz.

This gave me the DC factor of 5e-8.


The spectra at 1109832200 (ALS only, even not on the resonance) and 1109832500 (after DARM/CARM transitions) were taken.
Jenne said that the whitening filters for AS55Q was not on.

  17051   Mon Aug 1 17:19:39 2022 CiciSummaryGeneralRPitaya Data on Jupyter Notebook

Have successfully plotted data from the Red Pitaya on Jupyter Notebook! Have lost years of my life fighting with PyQt. Thanks to Deeksha for heavy contribution. Next task is to get actually good data (seeing mostly noise right now and haven't figured out how to change my input settings) and then to go to set up the RPi in the lab.

  13365   Fri Oct 6 12:56:40 2017 gautamSummaryLSCRTCDS NN

[gabriele, gautam]

Gabriele had prepared a C code implementation of his NN for MICH/PRCL state estimation. He had been trying to get it going on some of the machines in WB, but was unsuccessful. The version of RCG he was trying to compile and run the code on was rather dated so we decided to give it a whirl on our new RCG3.4 here at the 40m. Just noting down stuff we tried here:

  • Code has been installed at /opt/rtcds/userapps/release/cds/c1/src/nn.This is to facilitate compilation by the RCG.
  • There is also a simulink block diagram (x3tst.mdl) in there which we copied and pasted into c1pem. Changed the appropriate paths in the C-Code block to point to the location in the previous bullet point.
  • c1pem was chosen for this test as it runs at 2k which is what the network is designed for.
  • Since we were running the test on c1sus and expected the machine to crash, I shutdown all the watchdogs for the test.
  • Code compiled without any problems (i.e. rtcds make c1pem and rtcds install c1pem executed successfully). There were some warning messages related to C-Code blocks but these are not new, they show up in all models in which we have custom C-code blocks. 
  • Unfortunately, the whole c1sus FE crashed when we tried rtcds restart c1pem.
  • We tried a couple of more iterations, and attempted to monitor dmesg during the restart process to see if there were any clues as to why this wasn't working, but got nothing useful.

All models have been reverted to their state prior to this test, and everything on the CDS_OVERVIEW MEDM screen is green now.

  14122   Wed Aug 1 19:41:15 2018 gautamSummaryComputersRTCDS recovery, c1ioo changes

[Gautam Koji]

After this work, we recovered the nominal RTCDS state. The main points were:

  1. We needed to restart the bind9 service on chiara such that the FEs knew their IP addresses upon reboot and hence, could get their root filesystems over NFS.
  2. We recovered suspension local damping, IMC locking and POX/POY locking with nominal arm transmission.

Some stuff that is not working as usual:

  1. The EX QPD is reporting strange transmission values - even with the PRM completely misaligned, it reports transmission of ~30. But we were able to lock the Xarm with the Thorlabs PD and revover transmission of ~1.15.
  2. 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.

I made a model change in c1x03 (the IOP model on c1ioo) to add a DAC part. The model compiled, installed and started correctly, and looking at dmesg on c1ioo, it recognises the DAC card as what it is. Next step is to use a core on c1ioo for a c1omc model, and actually try driving some signals.

Note that the only change made to the c1ioo expansion chassis was that a DAC card was installed into the PCIe bus. The adaptor card which allows interfacing the DAC card to an AI board was already in the expansion chassis, presumably from whenever the DAC was removed from this machine.

*I think I forgot to restart optimus after this work...

  15950   Sun Mar 21 19:31:29 2021 ranaSummaryElectronicsRTL-SDR for monitoring RF noise / interference

When we're debugging our RF system, either due to weird demod phases, or low SNR, or non-stationary noise in the PDH signals, its good to have some baseline measurements of the RF levels in the lab.

I got this cheap USB dongle (RTL-SDR.COM) that seems to be capable of this and also has a bunch of open source code on GitHub to support it. It also comes mith an SMA coax and rabbit ear antenna with a flexi-tripod.

I used CubicSDR, which has free .dmg downloads for MacOS.It would be cool to have a student write some python code (perhaps starting with RTL_Power) for this to let us hop between the diffierent RF frequencies we care about and monitor the power in a small band around them.

  6124   Thu Dec 15 11:47:43 2011 jamieUpdateCDSRTS UPGRADE IN PROGRESS

I'm now in the middle of upgrading the RTS to version 2.4.

All RTS systems will be down until futher notice...

  16935   Tue Jun 21 21:17:16 2022 yutaUpdateBHDRTS models for BHD added but PCIE error remaining

[Anchal, Yuta]

RTS models for BHD homodyne phase control (c1hpc) and angular control (c1bac) are created and added to c1sus2.
c1su2 and c1lsc models were modified accordingly.
We still have issues with IPC PCIE connection sending DCPD A and B signals to c1lsc and DC error 0x2000 in c1su2 model.

c1hpc (host: c1sus2) Attachment #1
 This model is for homodyne phase control.
 It can dither LO1, LO2, AS1, AS4 in POS and demodulate mixture of DCPD A/B signals for the phase control to feedback to those optics.
 It also sends DCPD A/B signals to c1lsc via cdsIPCx_PCIE.
 Dither and controls signals are sent to the optics via cdsIPCx_SHMEM.

c1bac (host: c1sus2)
 This model is for BHD angular control.
 It is basically the same as c1hpc, but it is for PIT and YAW dithering of LO1, LO2, AS1, AS4.

c1su2 (host: c1su2) Attachment #2
 LSC and ASCPIT/YAW feedback signals from c1hpc and c1bac via shared memory were added to send them to corresponding optics.
 Somehow Mux/Demux didn't work to send SHMEM signals inside the subsystem in the Simulink model (this works for ADC, but probably not for IPC stuff?), and we had hard time make-install-ing this model.

c1lsc (host: c1lsc) Attachment #3
 DCPD A/B signals from c1hpc via PCIE were added for our new error signals for LSC.

Starting and restarting the models
 After having some troubles make-install-ing modified models (be careful of goto and from tags!), we stopped all the models in c1sus, c1ioo, c1lsc, c1sus2 and started all of them, including new c1hpc and c1bac models.
 This somehow created RFM errors in c1scx and c1scy.
 So, we proceeded to do the same step we did in 40m/16887 and 40m/15646, now including c1sus2 for the restart.
 Initial attempt made c1lsc, c1sus, c1ioo mostly red, so scripts/cds/rebootC1LSC.sh was run again on pianosa.
 RFM issues for c1scx and c1scy were solved.
 Shared memory within c1sus2 seems to be working, but sending DCPD A/B signals from c1hpc to c1lsc is not working (see Attachement #4).

Next:
 - Fix C1:HPC-LSC_DCPC_A/B issue
 - Make/modify MEDM screens

  6125   Thu Dec 15 22:22:18 2011 jamieUpdateCDSRTS upgrade aborted; restored to previous settings

Unfortunately, after working on it all day, I had to abort the upgrade and revert the system back to yesterday's state.

I think I got most of the upgrade working, but for some reason I could never get the new models to talk to the framebuilder.  Unfortunately, since the upgrade procedure isn't document anywhere, it was really a fly by the seat of my pants thing.  I got some help from Joe, which got me through one road block, but I ultimately got stumped.

I'll try to post a longer log later about what exactly I went through.

In any event, the system is back to the state is was in yesterday, and everything seems to be working.

  6174   Thu Jan 5 20:40:21 2012 JamieUpdateCDSRTS upgrade aborted; restored to previous settings; fb symmetricom card failing?

After running into more problems with the upgrade, I eventually decided to abort todays upgrade attempt, and revert back to where we were this morning (RTS 2.1).  I'll try to follow this with a fuller report explaining what problems I encountered when attempting the upgrade.

However, when Alex and I were trying to figure out what was going wrong in the upgrade, it appears that the fb symmetricom card lost the ability to sync with the GPS receiver.  When the symmeticom module is loaded, dmesg shows the following:

[  285.591880] Symmetricom GPS card on bus 6; device 0
[  285.591887] PIC BASE 2 address = fc1ff800
[  285.591924] Remapped 0x17e2800
[  285.591932] Current time 947125171s 94264us 800ns 
[  285.591940] Current time 947125171s 94272us 600ns 
[  285.591947] Current time 947125171s 94280us 200ns 
[  285.591955] Current time 947125171s 94287us 700ns 
[  285.591963] Current time 947125171s 94295us 800ns 
[  285.591970] Current time 947125171s 94303us 300ns 
[  285.591978] Current time 947125171s 94310us 800ns 
[  285.591985] Current time 947125171s 94318us 300ns 
[  285.591993] Current time 947125171s 94325us 800ns 
[  285.592001] Current time 947125171s 94333us 900ns 
[  285.592005] Flywheeling, unlocked...

Because of this, the daqd doesn't get the proper timing signal, and consequently is out of sync with the timing from the models.

It's completely unclear what caused this to happen.  The card seemed to be working all day today, then Alex and I were trying to debug some other(maybe?) timing issues and the symmetricom card all of a sudden stopped syncing to the GPS.  We tried rebooting the frame builder and even tried pulling all the power to the machine, but it never came back up.  We checked the GPS signal itself and to the extend that we know what that signal is supposed to look like it looked ok.

I speculate that this is also the cause of the problems were were seeing earlier in the week.  Maybe the symmetricom card has just been acting flaky, and something we did pushed it over the edge.

Anyway, we will try to replace it tomorrow, but Alex is skeptical that we have a replacement of this same card.  There may be a newer Spectracom card we can use, but there may be problems using it on the old sun hardware that the fb is currently running on.  We'll see.

In the mean time, the daqd is running rogue, off of it's own timing.  Surprisingly all of the models are currently showing 0x0 status, which means no problems.  It doesn't seem to be recording any data, though.  Hopefully we'll get it all sorted out tomorrow.

  6173   Thu Jan 5 09:59:27 2012 JamieUpdateCDSRTS/RCG/DAQ UPGRADE TO COMMENCE

RTS/RCG/DAQ UPGRADE TO COMMENCE

I will be attempting (again) to upgrade the RTS, including the RCG and the daqd, to version 2.4 today.  The RTS will be offline until further notice.

  16428   Tue Oct 26 14:53:24 2021 KojiUpdateElectronicsRack

1. We have a rack at the 40m storage. We are free to take it to the lab. If there is a tag, tell the info to Liz. Let's move it to the lab tomorrow right after the meeting.

2. We have a few racks in WB B1 (Attachment 1). Liz and I checked a rack which looks suitable for us. 46U height. Caltech transport will move it to the lab.

  17197   Tue Oct 18 15:24:48 2022 TegaUpdateCDSRack 1X7 work proposal

We have decided to split the remaining CDS work on rack 1x7 into two phases, both of which end with us bringing the 40m systems back up.

 

Phase 1 (Clear rack 1X7 of all mounted pieces of equipment)

  • Move nodus to 1X6 bottom slot
  • Move optimus to 1X6 (replaces old fat FB which can be moved to storage)
  • Move DAQ and network switches to the top of 1X7 rack
  • Move the UPS to under 1X6
  • Clear 1X7 power rail of any connections

 

Phase 2 (Replace the mounting rails and mount all pieces of equipment)

  • Mount DAQ, network and Dolphin switches at the top rear of 1x7 rack
  • Mount 6 new front-ends
  • Mount KVM switch
  • Move nodus back to 1X7
  • Move optimus back to 1X7

 

  16458   Mon Nov 8 18:42:38 2021 KojiSummaryBHDRack Layout / Power Strips
Rack # of units that
requires +18V
Power Source
1X3 (new rack) 15 1X3 U1/2
1X4 13 1X3 U1/2
1X5 8 or 9 (OL AA) 1X5 U40/41
1Y0 17 1Y0 U1/2
1Y1 15 1Y0 U1/2
1Y3 12 1Y3 U39/40
1X9 9 1X9 U38/39
1Y4 9

1Y4 U39/40

Notes:

  • There are 8 racks and there is only 7x 18V power strips. 1X5 could be the one without the power strip and to parasite with 1X3/4. Otherwise we need to modify some of the 24V power strips (no plan to use) into 18V by replacing the connectors.
  • We need total ~100 18V cables / We ordered 60x 3ft / 60x 3ft / 30x 10ft. Hopefully these are enough for our depand... I haven't checked the delivered number.
  • All the acromags are supposed to be powered with one voltage. I think they are supposed to run with +18V.
  • I didn't check the distribution of Sorensens through the lab. (i.e. how many we have / how many we need / ...)
  14869   Tue Sep 10 16:10:40 2019 ChubUpdate Rack Update

Still removing old cable, terminal blocks and hardware.  Once new strain reliefs and cable guides are in place, I will need to disconnect cables and reroute them.  Please let me know dates and times when that is not going to interrupt your work! 

  2953   Wed May 19 16:09:11 2010 josephbUpdateCDSRacks to small for IO Chassis rails

So I discovered the hard way that the racks are not standard width, when I was unable to place a new IO chassis into the racks with rails attached.  The IO chassis is narrow enough to fit through without the rails however. 

I've talked to Steve and we decided on having some shelves made.  I've asked Steve to get us 6.  1 for each end (2), 1 for SUS, 1 for LSC, 1 for IO, and 1 extra.

  2809   Mon Apr 19 16:27:13 2010 AidanUpdateGreen LockingRaicol crystals arrived and we investigated them

Jenne, Koji and I opened up the package from Raicol and examined the crystals under the microscope. The results were mixed and are summarized below. There are quite a few scratches and there is residue on some of the polished sides. There is a large chip in one and there appear to be gaps or bands in the AR coatings on the sides.

There are two albums on Picassa

1. The package is opened ...

2. The crystals under the microscope.

 

Crystal Summary
724 Chip in the corner of one end face, Otherwise end faces look clean. Large scratch on one polished side.
725 End faces look good. Moderate scratch on one polished face. Residue on one polished face.
726 Tiny dot on one end face, otherwise look okay. Large bands in one polished face. Moderate scratch on polished face
727 Large, but shallow chip on one polished face. End faces look clean. Bands in one of the polished faces.

 

  2816   Tue Apr 20 11:14:31 2010 AidanUpdateGreen LockingRaicol crystals arrived and we investigated them

 

 Here is Crystal 724 polished side 2 with all photos along the length stitched together

  1939   Tue Aug 25 01:27:09 2009 ranaConfigurationComputersRaid update to Framebuilder (not quite)

Quote:

The RAID array servicing the Frame builder was finally switched over to JetStor Sata 16 Bay raid array. Each bay contains a 1 TB drive.  The raid is configured such that 13 TB is available, and the rest is used for fault protection.

The old Fibrenetix FX-606-U4, a 5 bay raid array which only had 1.5 TB space, has been moved over to linux1 and will be used to store /cvs/cds/.

This upgrade provides an increase in look up times from 3-4 days for all channels out to about 30 days.  Final copying of old data occured on August 5th, 2009, and was switched over on that date.

 Sadly, this was only true in theory and we didn't actually check to make sure anything happened.

We are not able to get lookback of more than ~3 days using our new huge disk. Doing a 'du -h' it seems that this is because we have not yet set the framebuilder to keep more than its old amount of frames. Whoever sees Joe or Alex next should ask them to fix us up.

  1901   Fri Aug 14 10:39:50 2009 josephbConfigurationComputersRaid update to Framebuilder (specs)

The RAID array servicing the Frame builder was finally switched over to JetStor Sata 16 Bay raid array. Each bay contains a 1 TB drive.  The raid is configured such that 13 TB is available, and the rest is used for fault protection.

The old Fibrenetix FX-606-U4, a 5 bay raid array which only had 1.5 TB space, has been moved over to linux1 and will be used to store /cvs/cds/.

This upgrade provides an increase in look up times from 3-4 days for all channels out to about 30 days.  Final copying of old data occured on August 5th, 2009, and was switched over on that date.

  427   Fri Apr 18 16:48:13 2008 AndreyUpdatePEMRain collector of weather station

Today the rain collector of our weather station was cleaned. As a result, we checked that the rain indication on the weather monitor and on the MEDM screens is alive and working properly. I am adding some details about the roof sensors to the wiki-40 page about the weather station. See especially the link "More description of the roof sensors and their interaction with UNIX computers" from the main Weather Station page in wiki-40.

Pictures of the rain collector before (dirty, the opening is fully clogged with dust and dirt) and after (clean opening in the bottom of the bowl) the cleaning are attached.
  11283   Mon May 11 15:15:12 2015 manasaUpdateGeneralRan ASS for arms

Arm powers had drifted to ~ 0.5 in transmission.

X and Y arms were locked and ASS'd to bring the arm transmission powers to ~1.

  16398   Wed Oct 13 11:25:14 2021 AnchalSummaryCDSRan c1sus2 models in martian CDS. All good!

Three extra steps (when adding new models, new FE):

  • Chris pointed out that the sudo command in c1sus2 is giving error
    sudo: unable to resolve host c1sus2
    
    This error comes in when the computer could not figure out it's own hostname. Since FEs are network booted off the fb1, we need to update the /etc/hosts in /diskless/root everytime we add a new FE.
    controls@fb1:~ 0$ sudo chroot /diskless/root
    fb1:/ 0# sudo nano /etc/hosts
    fb1:/ 0# exit
    
    I added the following line in /etc/hosts file above:
    192.168.113.92  c1sus2 c1sus2.martian
    
    This resolved the issue of sudo giving error. Now, the rtcds make and install steps had no errors mentioned in their outputs.
  • Another thing that needs to be done, as Koji pointed out, is to add the host and models in /etc/rtsystab in /diskless/root of fb:
    controls@fb1:~ 0$ sudo chroot /diskless/root
    fb1:/ 0# sudo nano /etc/rtsystab
    fb1:/ 0# exit
    
    I added the following lines in /etc/rtsystab file above:
    c1sus2   c1x07  c1su2
    
    This told rtcds what models would be available on c1sus2. Now rtcds list is displaying the right models:
    controls@c1sus2:~ 0$ rtcds list
    c1x07
    c1su2
  • The above steps are still not sufficient for the daqd_ processes to know about the new models. This part is supossed to happen automatically, but does not happen in our CDS apparently. So everytime there is a new model, we need to edit the file /opt/rtcds/caltech/c1/target/daqd/master and add following lines to it:
    # Fast Data Channel lists
    # c1sus2
    /opt/rtcds/caltech/c1/chans/daq/C1X07.ini
    /opt/rtcds/caltech/c1/chans/daq/C1SU2.ini
    
    # test point lists
    # c1sus2
    /opt/rtcds/caltech/c1/target/gds/param/tpchn_c1x07.par
    /opt/rtcds/caltech/c1/target/gds/param/tpchn_c1su2.par
    
    I needed to restart the daqd_ processes in  fb1 for them to notice these changes:
    controls@fb1:~ 0$ sudo systemctl restart daqd_*
    
    This finally lit up the status channels of DC in C1X07_GDS_TP.adl and C1SU2_GDS_TP.adl . However the channels C1:DAQ-DC0_C1X07_STATUS and C1:DAQ-DC0_C1SU2_STATUS both have values 0x2bad. This persists on restarting the models. I then just simply restarted teh mx_stream on c1sus2 and boom, it worked! (see attached all green screen, never seen before!)

So now Ian can work on testing the I/O chassis and we would be good to move c1sus2 FE and I/O chassis to 1Y3 after that. I've also done following extra changes:

  • Updated CDS_FE_STATUS medm screen to show the new c1sus2 host.
  • Updated global diag rest script to act on c1xo7 and c1su2 as well.
  • Updated mxstream restart script to act on c1sus2 as well.
  52   Thu Nov 1 19:54:22 2007 Andrey RodionovBureaucracyPhotosRana's photo
  11635   Tue Sep 22 16:52:36 2015 ericqSummaryGeneralRandom Notes

Some things bouncing around my head that haven't made it to ELOG yet:

  • Last week, Rana and I were investigating excess power line noise coming from the DFD demodulation. We put transformers on the green beat signals where they arrive at the LSC rack, to avoid connecting their signal ground from the PSL table to the LSC rack ground. This didn't help; it's unclear what the culprit is; maybe the demod board power board?
  • Lately, when the interferometer loses lock, the Y arm will not lock on POY, or even flash its IR resonance. for a little while. The green beam can be locked, the X arm can be locked, and no excess angular noise is evident from glancing at the oplev XY plots. Mysterious.  
  • Sometimes, when writing new values to the C1LSC SDF table, the c1lscepics process dies (though the write is successful). This is highly annoying. This may have been adressed in some slightly newer RCG code. 
  • C1OAF is running with a big red NO SYNC message on its GDS screen. C1LSC has shown this too, but I think only when the SDF/epics crash happens. 
  • C1OAF also doesn't seem to properly load the "safe" SDF table when starting up, and errantly puts ones in every element in the static FF matrix. Be careful when restarting OAF!
  2430   Thu Dec 17 23:27:23 2009 ranaUpdatePEMRanger Noise: sim w. Rai FET box as readout

I have started measuring the low frequency noise of the FET front end + LT1128 low noise preamp from Rai Weiss. It has a very low input current noise because its FET based, which is not surprising. It is also a fairly low voltage noise box - the best measured ones have an input referred noise of ~0.35 nV/rHz.

Today I measured the noise of the one we have down to 0.1 Hz. It looks like a good candidate for a Geophone readout (e.g. Ranger or GS-13 or perhaps the L-4C). Because I didn't thermally shield any of this stuff, the broadband noise is ~0.8 nV/rHz. The low frequency corner is ~15 Hz.

I attach the LISO simulation of the voltage noise referred to the input. The circuit is described in this entry.

We can probably do better than this if we package it a little better or give it time to warm up or use metal film resistors inside. Even as it is, however, it would allow us to reach the thermal noise of the Ranger (or GS-13) down to 0.1 Hz.

This should be ~1.5 or 2x better than the LT1012 based readout at 1 Hz and 10x better down at 0.1 Hz (c.f. T0900457).

  363   Fri Mar 7 00:47:54 2008 ranaConfigurationPEMRanger SS-1
Yesterday evening around 7:30 PM, I changed the Ranger seismometer from a
vertical to a horizontal seismometer. To do this I followed the instructions
in the manual.
1) Lock it down.
2) Turn it sideways. Use the leveling screws to center the bubble level.
3) Carefully loosen the hanger rod and release slowly the tension to allow
   the mass to recenter.
4) Look through the little viewhole next to the rod to make the white lines
   line up. This means the mass is centered.
5) Look at the output on a scope. It should be freely moving with a ~1 sec.
   period.

The attached plot shows the before and after spectra.
  881   Mon Aug 25 15:50:18 2008 ranaSummaryPEMRanger SS-1
The manual for the Ranger SS-1 seismometer can be found on line here:
ftp://ftp.kmi.com/pub/software_manuals/300190/300190nc.pdf

and now in our 40m PEM Wiki page:
Ranger_SS-1

To calibrate it, we use the formula from the manual:
                 R_x
G_L = G_0 * ------------   =  149 +/- 3 V/(m/s)
             R_x  +  R_c

where
G_0 = 340 V/(m/s)    (generator constant)
R_x = 4300 Ohms      (external damping resistor in Pomona box)
R_c = 5500 Ohms      (internal coil resistance)

Then we have a gain of 200 in the SR560 so that gets us to ~30000 V/(m/s).

And then there's a DAQ conversion factor of the usual 2^16 cts / 4 V.

so the calibration constant is

G = 488 counts / (micron/sec)

in the ~1-50 Hz band
  1167   Tue Dec 2 19:18:10 2008 ranaSummaryPEMRanger SS-1
In entry http://dziban.ligo.caltech.edu:40/40m/881 and a follow up from Jenne I put in the Ranger calibration.
Since then, we've reduced the SR560 gain from 200 to 100 so the calibration factor is now:

1e-9 (m/s)/count and then 2 poles at 0 Hz, and a Q~1 zero pair at 1 Hz.
in DTT:
G = 1e-9
p = 0, 0
z = 0.7 0.7
  391   Fri Mar 21 23:15:11 2008 ranaConfigurationPEMRanger SS-1: New Setup
The Ranger seismometer has been in a bad state. Its output had been sent into a SR560 without any termination.

The seismometer is, internally, just a mass on a flexure with a magnet and a pickup coil for readout.
The damping of the system depends on the resistor hooked up across the coil. With the SR560 this is
the 1 Meg input impedance of it and so the mass is undamped.

I installed a 4300 Ohm resistor in there which seems to nearly critically damp it. However, this will not
allow us to reach the ultimate quantum noise limited performance. We will have to analyze the thermal, voltage,
and current noise to get that.

I then also increased the gain from 10 to 100 on the SR560. This should now make the front end noise of the
seismometer/SR560 close to equal to the noise of the PEM ADC.
  1171   Wed Dec 3 19:21:09 2008 ranaConfigurationPEMRanger move
I looked at the Ranger signals. Somehow it has a relative transfer function of 'f' between it and the Guralp.
      Ranger
i.e.  ------ ~ f
      Guralp

which is strange since according to their manuals, they should both be giving us a voltage output which is proportional
to velocity. I checked that the Ranger only has a load resistor and then an SR560 low pass at 300 Hz. Jenne assures
me that the Guralp breakout box shouldn't have any poles either (to be double checked). Its a mystery.

We made sure that the SR560 now is DC coupled, G = 100, & 1-pole low pass at 300 Hz. I moved it over next to the Guralp
(went through the mass recentering procedure after forgetting to lock it before moving). It is behaving as it was
before.

Attached is a 2 page PDF of the comparisons. The 'MC1' channels are Guralp and 'MC2' is Ranger.

The second attachment compares our seismometers (in counts) with the LHO Guralp seismometers. There's no high frequency
rolloff there like what we see here so I bet a dollar that there's a pole in the Guralp box somewhere.
  2194   Fri Nov 6 16:27:15 2009 JenneUpdatePEMRanger moved

The Ranger seismometer has been moved to ~the middle of the Mode Cleaner tube, and it's orientation has been changed to horizontal (using all of the locking/mass centering procedures).  This is similar in orientation to the way things were back in the day when Rana and Matt had the OAF running nicely.

  2351   Fri Dec 4 18:54:03 2009 JenneUpdatePEMRanger moved

The Ranger was left in a place where it could be bumped during next week's activities (near the crawl-space to access the inside of the "L" of the IFO on the Yarm).  It has been moved a meter or so to a safer place.

Also, so that Steve can replace the battery in the SR560 that is used for the Ranger, I swapped it out with one of the ones which already has a new, charged battery.  All of the settings are identical.  For posterity, I took a pic of the front panel before unplugging the old SR560.

  1106   Sun Nov 2 21:37:22 2008 ranaUpdatePEMRanger recovery
The ranger signal has been bad since around 11 AM on Oct 25 (last Saturday). There are no elog
entries from that day, but I am quite sure that someone must have been working around the PSL
rack area.

It looks like what happened is that someone moved the chair with the monitor on it and/or the wooden
stool next to it. That put tension on the cable connecting the SR560 and the seismometer. The SR560
connector now seems loose and I think probably the cable ground wasn't connected. I swapped the
cable over to the "B" side of the SR560 and the ranger signal is now reasonable (very small offset
and normal seismic signal).

Please be careful when working around there. Everyone always says "I didn't do anything" or "it doesn't
effect anything".

We need to clean up the cabling around there in addition to running a new power cable for the RF amplifier
on the POY table.


I have also reduced its sample rate from 2048 to 512 Hz. The data are OK after 909640694.

I also increased the sample rate of AS_MIC from 2048 to 16384 Hz but that one seems to be broken
---->> the microphone seems to be either disconnected or broken.
  10067   Wed Jun 18 22:47:48 2014 ericqUpdateCDSRaspberry pi added to martian network

I set up a raspberry pi on the martian network, to be hooked up to a frequency counter for tracking ALS beatnotes. 

The instructions at https://wiki-40m.ligo.caltech.edu/Martian_Host_Table are outdated, the name server configuration is now at /etc/bind/zones/martian.db, I need to remember to update the wiki soon. 

In any case, the raspberry pi is called "domenica," is found at 192.168.113.107, and has the standard controls user, with /cvs/cds mounted in the same way as the control room machines. 

Once I'm comfortable with the configuration of the pi, I'm going to take an image of the SD card that serves as its hard drive, so that we can just image new cards for future raspberry pis on the martian network if we ever want them. 

  11965   Mon Feb 1 09:16:32 2016 SteveUpdatePEMRat got cut

We got it! Traps are removed.

 

  14186   Tue Aug 28 15:29:19 2018 SteveFrogsPEMRat is cut

The rat is cut by mechanical trap and it was removed from ITMX south west location.

A nagy kover patkanyt a fogo elkapta es megolte.

  11911   Tue Jan 5 15:48:16 2016 SteveUpdatesafetyRat trap locations

Please look around when working close to these five locations. Use flashlights or leave lights on.

These mechanial traps are HAZARDOUS !

No visitors or tours till Monday, Jan 11  2016

  11913   Tue Jan 5 17:19:57 2016 ranaUpdatesafetyRat trap locations

In the modern times, people use glue traps to catch rats instead of springs. They are less hazardous to people and don't spread rat fluid on the floor.

  11909   Tue Jan 5 09:48:52 2016 SteveUpdatePEMRat trap moved

Our janitor confirmed that Q was not hallucinating about this animal. The dropping size indicating a good size one in the IFO room.

One of the mechanical traps moved from the control room to the east arm, close to the " machine shop " door.

I'm going to get more traps.

Quote:

Two mechanical and two sticdky traps were set to catch univited visitor.

Absolutely no food or food remains into inside garbage cans!!!!!!!!!!!!!!!!!!!!!!!!!

Quote:

A small rat / large mouse just ran through the control room. Ugh.

 

 

  11895   Mon Dec 21 14:31:41 2015 SteveUpdatePEMRat traps set

Two mechanical and two sticdky traps were set to catch univited visitor.

Absolutely no food or food remains into inside garbage cans!!!!!!!!!!!!!!!!!!!!!!!!!

Quote:

A small rat / large mouse just ran through the control room. Ugh.

 

  11893   Sun Dec 20 23:23:54 2015 ericqUpdateALARMRats.

A small rat / large mouse just ran through the control room. Ugh.

  10657   Fri Oct 31 11:46:15 2014 manasaUpdate Rattling HEPA : Eventually stops

The PSL HEPA stopped working while it was running at 80%. I have closed the PSL enclosure.

Steve is working to fix this.

  6792   Mon Jun 11 16:08:58 2012 JenneUpdateEnvironmentRattling in the HEPA

There is an intermittent rattling sound coming from the HEPA in the NE corner of the PSL table (right above the PMC, all of our input optics).

Steve says it might be a bad bearing, but he'll check it out in the morning and get it fixed.

  6793   Mon Jun 11 21:35:55 2012 JenneUpdateEnvironmentRattling in the HEPA

Quote:

There is an intermittent rattling sound coming from the HEPA in the NE corner of the PSL table (right above the PMC, all of our input optics).

Steve says it might be a bad bearing, but he'll check it out in the morning and get it fixed.

 MC was having a hard time staying locked, with no discernable reason from the control room (i.e. no big seismic, no PMC PZT railing).    The HEPA was on 100%, so I turned it down to 50% to hopefully reduce the rattling, if that was what was wrong. 

  10103   Wed Jun 25 17:49:36 2014 HarryUpdateGeneralRazorblade Analysis Pt. 2

Reconfigured razorblade analysis setup on the PD table as per instructions. Used it to collect data to calculate beam waist with, analyses to follow.

See attached schematic for optical setup.

  10083   Fri Jun 20 18:33:53 2014 HarryUpdateGeneralRazorblade Beam Analysis Setup

 Eric Q and I set up the optical configuration for razorblade beam analysis on SP table for future use.

It has been aligned, and will be in use on Monday.

The beam will be characterized for future characterization of optical fibers.

ELOG V3.1.3-