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ID Date Author Type Categoryup Subject Text Attachments
  15365   Wed Jun 3 01:40:13 2020 gautamUpdateElectronicsMore electronics woesThere were many locklosses from the point
where the arm powers were somewhat stabilized.
 glitchySeis2.pngglitchySeis3.png 
  15433   Fri Jun 26 16:53:38 2020 gautamUpdateElectronicsRFPD characterizationSummary:

While the vacuum system was knocked
out, I measured the RF transimpedance (using
 WFS1.pdfWFS2.pdfbuildupMons.pdf 
  15439   Mon Jun 29 15:56:02 2020 gautamUpdateElectronicsRFPD characterizationA more comprehensive report has been uploaded
here.
I'll zip the data files and add them
  
  15443   Tue Jun 30 22:00:04 2020 gautamUpdateElectronicsGlitchy POX resurfacesThis
problem reared its ugly head again. I
am inclined to believe the problem is electronic
 glitchyPOX.jpg 
  15450   Sun Jul 5 18:25:42 2020 ranaUpdateElectronicsWFS characterizationin the lab, checkin on the WFS

Sun Jul 5 18:25:50 2020

I redid Gautam's measurements
 WFS_attenOff.pdf 
  15472   Sun Jul 12 22:40:35 2020 gautamUpdateElectronicsWFS characterization - old SURF reportAfter some hunting, I found this
old SURF report with the WFS head measurements.
The y-axes don't make much sense to me,
  
  15480   Tue Jul 14 16:52:47 2020 gautamUpdateElectronicsCoil drivers for the test massesSummary:

Koji and I had a discussion last
Friday about the suspension electronics.
 coilDriverSchem.pdf 
  15488   Wed Jul 15 21:08:43 2020 gautamUpdateElectronicsETM coil outputs DQedTo facilitate this investigation, I've
DQed the 4 face coil outputs for the two
ETMs. EX is currently running with 5 times
 CDS.pngcoilOutDQed.png 
  15494   Mon Jul 20 17:23:46 2020 gautamUpdateElectronicsCoil drivers for the test massesSummary:

Looking at the signals to the test
mass coils, it seems borderline
 ALSlock_timeDomain.pdfALSlock.pdfRFlock.pdf 
  15516   Wed Aug 12 17:42:58 2020 gautamUpdateElectronicsPhotodiode inventorySee Attachments
#1 and #2.
 IMG_8709.JPGIMG_8708.JPG 
  15517   Wed Aug 12 18:08:54 2020 gautamUpdateElectronicsNumber of the beastThe "source"
output of the SR785 has a DC offset of -6.66
 IMG_8710.JPG 
  15519   Wed Aug 12 20:15:42 2020 KojiUpdateElectronicsNumber of the beastGrrr. Let's repair the unit. Let's
get a help from Chub & Jordan.

Do you have a second unit in the
  
  15520   Wed Aug 12 20:16:52 2020 KojiUpdateElectronicsPhotodiode inventoryWhen I tested Q3000 for aLIGO, the failure
rate was pretty high. Let's get 10pcs.
  
  15534   Thu Aug 20 00:21:51 2020 gautamUpdateElectronicsFirst look at HV coil driverSummary:

A single channel of this
board was stuffed (and other channels
 IMG_8724.JPGtimeDomain.pdfHVampNoise.pdf 
  15536   Sun Aug 23 23:36:58 2020 gautamUpdateElectronicsFirst look at HV coil driverSummary:

A more careful analysis has revealed
some stability problems. 
 IMG_5379.JPGstabilityCriterion.pdf 
  15542   Wed Aug 26 16:12:25 2020 gautamUpdateElectronicsTest mass coil current requirementsAttachment
#1 is a summary of
 coilCurrents.png 
  15543   Wed Aug 26 22:49:47 2020 gautamUpdateElectronicsCheckout of Trek Model 603I unboxed
the Trek amplifier today, and performed some
basic tests of the functionality. It seems
 IMG_8951.JPG 
  15547   Sat Aug 29 20:07:48 2020 ranaUpdateElectronicsWFS characterizationI set up to do the WFS head modifications
today, but I was shot down in flames due
to a missing AC/DC adapter.
  
  15548   Sat Aug 29 22:10:09 2020 gautamUpdateElectronicsWFS characterizationClearly this "riff raff" is referring
to me. It won't help today I guess but
there is one each on the carts holding the
  
  15551   Tue Sep 1 01:49:49 2020 KojiUpdateElectronicsTeledyne AP1053 etc were transportedTeledyne AP1053 etc were transported from
Rich's office to the 40m. The box is
placed on the shelf at the entrance.
 20200831203756_IMG_9931.jpg20200831203826_IMG_9932.jpg20200831205126_IMG_9934.jpg 
  15552   Tue Sep 1 15:39:04 2020 gautamUpdateElectronicsHV coil driver oscillations fixedSummary:

Increasing the compensation capacitance
(470 pF now instead of 33 pF) seems to have
 testSetup.pdfHVampNoise_driven.pdf 
  15571   Tue Sep 15 12:20:36 2020 gautamUpdateElectronicsSR785 repairedThe unit was repaired and returned to the
40m. Now, with a DMM, I measure a DC offset
value that is ~1% of the AC signal amplitude.
 dividerTF.pdf 
  15572   Tue Sep 15 17:04:43 2020 gautamUpdateElectronicsDC adaptors deliveredThese were delivered to the 40m today and
are on Rana's desk

  
  15613   Mon Oct 5 14:01:41 2020 gautamUpdateElectronicsaLIGO demod boards stuffed and deliveredWe received 20pcs of stuffed
demodulator
boards from Screaming Circuits today.
 IMG_8888.JPG 
  15633   Mon Oct 19 15:38:42 2020 KojiUpdateElectronicsLoan: A file binder "40m wiring diagram" I'll bring a file binder "40m
wiring diagram" to home at the next
chance.
  
  15636   Thu Oct 22 11:14:47 2020 gautamUpdateElectronicsHV coil driver packaged into 2U chassisI packaged the HV coil driver into a 2U
chassis, hoping for better shielding from
pickup. There
 HVampNoise_driven_chassis.pdfHVampNoise_dispUnits.pdfD1900163_measurementSetup.zip 
  15638   Thu Oct 22 13:04:42 2020 ranaUpdateElectronicsHV coil driver packaged into 2U chassiswhat is the noise level before the HV stage?
i.e. how well is the acromag noise being
filtered?
  
  15639   Thu Oct 22 22:01:53 2020 gautamUpdateElectronicsHV coil driver packaged into 2U chassisIt's not so easy to directly measure
this I think, because the filtering is rather
aggressive. 
 DACnoiseFilterGain.pdfDACnoiseFilterNoises.pdf 
  15640   Fri Oct 23 09:03:43 2020 anchalUpdateElectronicsHV coil driver packaged into 2U chassisAndrew made a battery-powered 0.7 nVrtHz
input-referred noise pre-amplifier for gain
of 200. That might help you.
  
  15674   Thu Nov 12 14:31:27 2020 gautamUpdateElectronicsSR560s in need of repair/battery replacementI had to go through five SR560s
in the lab yesterday evening to find one
that had the expected 4 nV/rtHz input noise
 IMG_8947.jpg 
  15675   Thu Nov 12 14:55:35 2020 gautamUpdateElectronicsMore systematic noise characterizationSummary:

I now think the excess noise in
this circuit could be coming from the KEPCO
 powerSupplyNoise.pdfcoherence.pdf 
  15676   Thu Nov 12 15:40:42 2020 KojiUpdateElectronicsMore systematic noise characterizationYes. The datasheet has a recommendation
circuit with 10uF caps. Companies are careful
to show reproducible, reliably functional
  
  15677   Mon Nov 16 00:02:34 2020 ranaUpdateElectronicsMore systematic noise characterizationtrue. also try to choose a cap with a goow
high frequency response. In the Electronics
Noise book by Ott there's some graph
  
  15679   Tue Nov 17 00:26:32 2020 ranaUpdateElectronicsSR560s in need of repair/battery replacementyes, both problems can be fixed. Usually
we just order some spare lead-acid batteries
from SRS (Steve may have some spare ones
  
  15699   Thu Dec 3 10:46:39 2020 gautamUpdateElectronicsDC power strip requirementsSince we will have several new 1U / 2U
aLIGO style electronics chassis installed
in the racks, it is desirable to have a more
  
  15700   Thu Dec 3 11:02:35 2020 ranaUpdateElectronicsElectrical LO signal for AS WFSlooks good to me.

The thing I usually look for is
how much the downstream system (mixers, etc)
  
  15709   Fri Dec 4 19:23:40 2020 KojiUpdateElectronicsAA/AI board testing ongoingI have the setup built for the AA/AI board
testing around the PD testing area. Please
let me leave it like that for a week or so.
  
  15735   Tue Dec 15 12:38:41 2020 gautamUpdateElectronicsDC power stripI installed a DC power strip (24 V
variant, 12 outlets available) on the NW
upright of the 1X1 rack. This is for the
  
  15741   Sat Dec 19 20:24:25 2020 gautamUpdateElectronicsWFS hardware installI installed 4 chassis in the rack 1X2 (characterization
on the E-bench was deemed satisfactory, I
will upload the analysis later). I ran out
  
  15773   Wed Jan 20 10:13:06 2021 gautamUpdateElectronicsHV Power supply bypassingSummary:

Installing 10uF bypass capacitors
on the High
 bypassCaps.pdfIMG_9079.jpgIMG_9078.jpgHVampNoise_driven_chassis.pdfprintCoilCurrents.pdf 
  15786   Mon Feb 1 12:30:21 2021 gautamUpdateElectronicsMore careful characterizationSummary:


Swapping out the KEPCO
HV supplies (linear) I was using for a pair
 HVPS.pdfHV_testckt.pdftotalNoise.pdf 
  15798   Wed Feb 10 14:14:58 2021 gautamUpdateElectronicsCustom cables receivedWe received the custom cables to test the
new suspension electronics. They are under
my desk. So we are ready.
 satWiring.pdf 
  15802   Wed Feb 10 21:14:03 2021 gautamUpdateElectronicsProduction version of the HV coil driver testedSummary:

I did what I consider to be a comprehensive
set of tests on the production version of
 inputDiffRecTF.pdfLVnoises.pdftotalNoise.pdftimeDomainTests.pdf 
  15815   Thu Feb 18 03:20:09 2021 KojiSummaryElectronicsCurrent Rack MapFor your planning:  rack_plan.pdf 
  15820   Thu Feb 18 20:24:48 2021 KojiSummaryElectronicsA bunch of electronics receivedTodd provided us a bunch of electronics.
I went to Downs to pick them up this afternoon
and checked the contents in the box. Basically,
 IMG_0416.jpeg 
  15828   Sat Feb 20 10:01:48 2021 gautamSummaryElectronicsA bunch of electronics receivedWill we also be receiving the additional
34 Satellite Amplifier PCBs?
  
  15830   Sat Feb 20 16:46:17 2021 KojiSummaryElectronicsA bunch of electronics receivedWe received currently available sets. We
are supposed to receive more coil drivers
and sat amps, etc. But they are not ready
  
  15846   Fri Feb 26 16:31:02 2021 gautamUpdateElectronicsProduction version of the HV coil driver tested with KEPCO HV suppliesKoji asked me to test the production version
of the coil driver with the KEPCO HV supplies.
See 
 totalNoise_KEPCO.pdf 
  15847   Fri Feb 26 20:20:43 2021 KojiUpdateElectronicsProduction version of the HV coil driver tested with KEPCO HV suppliesThis is very disappointing. Even with KEPCO
linear supply with the improved HV driver
circuit, the noise level is significantly
  
  15848   Sat Feb 27 17:25:42 2021 gautamUpdateElectronicsProduction version of the HV coil driver tested with KEPCO HV suppliesI will try the test of switching out KEPCOs
one at a time for the HP. Given that the
passive RC filter doesn't filter
  
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