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ID Dateup Author Type Category Subject Text Attachments
  2215   Tue Jul 24 13:47:48 2018 anchalDailyProgressISSIntroduced zero to cancel cavity pole. Mostly final circuit.Here is LISO analysis on the version 2
of this circuit. I'll take Johannes'
advice and remove the active filter on stage
  2216   Tue Jul 24 14:28:08 2018 johannesDailyProgressISSIntroduced zero to cancel cavity pole. Mostly final circuit.Modified the design to make stage three
passive again and moved stage 5 (addition
of offset) to stage 4. PFA the circuit schematic.
  2217   Thu Jul 26 18:30:51 2018 anchalDailyProgressISSNoise analysis of soldered circuitI soldered the servo circuit on a prototype
board. The transfer function of the soldered
board is matching very well with the analytical
  2218   Fri Jul 27 12:29:43 2018 ranaDailyProgressISSNoise analysis of soldered circuitfor any circuit where power noise is measured,
the units should be input referred current
noise, not voltage noise. So you have to
  2219   Mon Jul 30 13:28:37 2018 anchalDailyProgressISSNoise analysis of soldered circuitJust replotting the measured noise with
LISO prediction for comparison.
  2220   Mon Jul 30 16:54:50 2018 anchalDailyProgressISSUnderstanding the ISS box we foundI was given an ISS box which was made in
2013. It is numbered D1300694-v1 and the
schematics are present in DCC. I tried to
  2221   Mon Jul 30 18:58:27 2018 anchalDailyProgressISSMinor version improvement in design.It seems difficult to implement our AC
coupled circuit in D1300694_v1 board which
is DC coupled.
  2222   Wed Aug 1 11:16:22 2018 anchalDailyProgressISSFinal Design for ISS Servo v3.2I checked with some replacements of opamp
at stage 1 to reduce the noise due to current
noise. It seems AD743 is the best balanced
  2223   Wed Aug 1 17:31:19 2018 awadeDailyProgressISSFinal Design for ISS Servo v3.2AD743 is discontinued.  We have
a few in stock, and there are still a few
SOIC-16 version that you can buy. 
  2224   Sat Aug 4 21:37:55 2018 johannesDailyProgressISSFinal Design for ISS Servo v3.2These are some "low-noise" FET
input OpAmps which are all still alive:


  2225   Mon Aug 6 15:02:57 2018 anchalDailyProgressISSFinal Design for ISS Servo v3.2Yes I realized this later. AD743, unfortunately,
was the best choice for us. Its replacement
ADA4627 from Analog Devices is worse than
  2226   Mon Aug 13 17:36:39 2018 anchalSummaryPDPhotodiode Transimpedance Amplification CircuitRedesigned D1400384-v2 is ready and uploaded
on dcc. PCB
Layout, circuit schematic, Gerber files,
  2227   Mon Aug 13 17:41:39 2018 anchalSummaryISSDCC link of finished designThe board design is finished and all the
files have been uploaded on dcc (LIGO-D1800214-v1). PCB
  2228   Wed Aug 29 12:01:54 2018 anchalSummaryPMCSummarization of efforts to fix PMC Servo problemsI and Andrew measured transfer functions
of each stage of PMC Servo box using Agilent
4395A and HP 41800A probe. Attached are the
  2229   Thu Aug 30 12:01:37 2018 ranaSummaryPMCSummarization of efforts to fix PMC Servo problemspost up-to-date schematic

Update Thu Aug 30 15:13:48 2018:
now added to elog 2228
  2230   Fri Sep 7 23:23:00 2018 awade, anchalDailyProgressBEATBack to beat[awade, anchal​]

Today we go the beat to converge
on the 26 MHz resonance of the resonant transmission
  2231   Sat Sep 8 17:34:54 2018 awadeMiscComputersWS1 CPU fan deadWS1, the main computer in the PSL lab died
last night.  On reboot bios screen says
that CPU fan died.  
  2232   Wed Sep 12 16:27:19 2018 anchalDailyProgressBEATBack to beatAttached are transfer function measurements
of the North and South Cavity Reflection
RFPD (14.75MHz resonant RFPD) along with
  2233   Fri Sep 14 00:57:14 2018 ranaDailyProgressBEATBack to beatplease replace TF and noise plots
with ones that have physical
units on the y-axis: V/A
  2234   Mon Sep 17 14:08:56 2018 awadeMiscComputersWS1 CPU fan replacedFound that WS1 had died again.  CPU
fan seized up again.

Replaced and computer restarted
  2235   Wed Sep 19 20:11:24 2018 awade, anchalDailyProgressFSSInstalling OCXO preamp 36 MHz + 37 MHz[awade, anchal]

TL:DR The OCXO preamp seemed
to have a very high current draw, looking
  2236   Fri Sep 21 11:24:42 2018 anchal and awadeDailyProgressFSSEOM Drivers TFWe have replaced the resonant 14.75MHz
EOM from south path with a broadband EOM
(Newport 4004). We soldered two
  2237   Fri Sep 21 18:10:53 2018 ranaDailyProgressBEATBack to beatI don't understand what that means.
Please provide 10x more details on how the
measurement was made.
  2238   Mon Sep 24 12:49:20 2018 awadeDailyProgressFSSModifying TTFSS box LP elliptical filtersAfter we improved the performance of the
PMC locking -- that was degraded because
of excessive RF getting past the demodulation
  2239   Mon Sep 24 12:53:26 2018 awade and anchalSummaryPMCSummarization of efforts to fix PMC Servo problems: external mixer and LP filter[awade and anchal]

  2240   Wed Sep 26 16:59:17 2018 anchalSummaryFSSCharacteristics of new RFPDs in FSSWe installed new RFPDs with components
s.t. they are tuned near 35.5 MHz. We tuned
the inductor L1 and capacitor C40 to bring
  2241   Wed Sep 26 17:17:18 2018 anchalNotesPDCaution about RF Cage in resonant RFPDsThe RF Cage that goes on top of the circuit
in resonant RFPDs is grounded. It helps in
avoiding interferance, however, if some component,
  2242   Thu Sep 27 10:58:58 2018 awade and anchalDailyProgressFSSFirst FSS lock 36 MHz north pathWe hooked up the 36 MHz crystal source
to the TTFSS boxes and EOM driver yesterday
and scanned the north cavity to see the error
  2243   Mon Oct 1 17:38:00 2018 awade and anchalDailyProgressFSSSouth Path misaligned and mismatched; time for PMCAfter putting in the new EOM driver at
37 MHz, we have been unable to mode match
into the south cavity. After beam profiling
  2244   Mon Oct 1 23:44:59 2018 ranaSummaryFSSCharacteristics of new RFPDs in FSSPlease explain in much
more detail how the RF transimpedance calibration
was done.
  2245   Fri Oct 5 12:42:29 2018 awadeDailyProgressPDPMC reflection PD DC path fixThe DC path of the north PMC resonant reflection
photodetector was not showing any signal.

Some work on the North PMC
  2246   Mon Oct 8 10:22:09 2018 awadeSummaryRFSome notes on reflectionless RF filters for demodulation electronicsEdit Thu Oct 25 14:57:57 2018 (awade):
Note that the LISO models here have wrong
units.  They are supposed to be in units
  2247   Mon Oct 8 15:10:17 2018 anchalSummaryPDTransimpedance and Dark Noise measurement of all RFPDs in PSLtl;dr:

  2248   Thu Oct 11 12:02:46 2018 anchalSummaryPMCSouth PMC servo card ready to useI have mounted south PMC servo card on
a 1U chassis with two acromag cards.
The card should be ready to use.
  2249   Fri Oct 12 14:41:17 2018 awadeSummaryEnvironmentTemperature logging PSL lab (Sep-Oct 2018)Temperature data in the ATF (QIL) lab has
been collected for a month now.  Data
is sampled at 0.1 s intervals and saved
  2250   Fri Oct 19 17:05:10 2018 anchalSummaryNoiseBudgetSummary of present noise budgetAttached is the latest full noise budget
we have. I generated it by rerunning current
  2251   Tue Nov 6 13:41:04 2018 anchalSummaryPMCPMC installed on South PathChanges:

PMC on the south path has been installed
with the PMC servo card on the rack.
  2252   Mon Nov 12 11:53:50 2018 anchalNotesopticChanged half waveplate angle after South EAOMFor some reason after the weekend, I found
that the laser power on the south path decreased
by about 300 uW. On checking power with a
  2253   Sun Nov 18 18:50:39 2018 anchalSummarySouth CavitySouth Path up and running againThe South PMC is installed and the South
FSS is running again. Attached is the beam
path profile from ala mode used for the south
  2254   Tue Nov 20 17:31:13 2018 anchalDailyProgressOtherPrecav Beatnote Freq counter and PID optimizationI learned today from Andrew on how to setup
the pre-cavity beat note frequency counter
and use it for cavity heater PID. Now, I
  2255   Wed Nov 21 17:54:00 2018 anchalDailyProgressTempCtrlNotes about Cavity Heater PIDLast night I ran PIDAutoTune.py for Cavity

Breif description
  2256   Wed Nov 21 19:33:23 2018 awadeMiscElectronics EquipmentSR785 (SN46950)The main SR785 (Serial number 46950) has
a dead screen. 

I power cycled the unit and also
  2257   Thu Nov 22 12:49:35 2018 anchalDailyProgressTempCtrl The configuration run:

ran overnight PIDAutoTune with following
  2258   Wed Nov 28 10:42:47 2018 anchalNotesTempCtrlTemperature control efforts in last few daysTying the estimated PID coefficients:

the configuration run (see
PSL:2257), I estimated some new PID coefficients.
  2259   Wed Nov 28 19:50:20 2018 ranaNotesTempCtrlTemperature control efforts in last few daysseems a little too much like hunt and peck.
Don't you have a time domain simulation
of the plant? If not, why not?
  2260   Mon Dec 3 10:44:19 2018 anchalNotesTempCtrlPlan of action for installing new heater shield and temperature sensorsWe have come to the conclusion that to
properly tune PID, we need to accurately model
a physical system that represents the cavity
  2261   Tue Dec 4 15:05:56 2018 anchalDailyProgressTempCtrlOptimal circuit for transimpedance of temperature sensor for Vacuum CanChoosing better TIA opamp (Continued
from ATF:2250):

summarizing the analysis of Awade and Zach
  2262   Fri Dec 7 11:26:30 2018 awadeMiscDAQFrame builder back upFramebuilder has been down for months now. 
It looks like I've been able to get it
up and going again albeit with the same issues
  2263   Mon Dec 10 15:40:51 2018 anchalSummaryTempCtrlPrototype results for transimpedance circuit for Vacuum Can Temperature SensorI soldered a prototype board implementing
the transimpedance circuit I, Andrew and
Rana discussed earlier.
  2264   Thu Dec 13 15:34:33 2018 anchalDailyProgressTempCtrlProposed circuit for cavity temperature sensorI have designed a circuit for using RTDs
for sensing temperature of the cavities.

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