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Reports until 14:48, Tuesday 27 November 2012
H1 CDS
david.barker@LIGO.ORG - posted 14:48, Tuesday 27 November 2012 (4773)
CDS Maintenance

WP# 3576,3577,3578,3581

busy maintance day today, four separate work permits!

WP3576 IOP SUS Watchdog bypass time extension. Following extending MC2's bypass time on h1iopsush34, today we did the same for h1sush2a (MC1 and MC2). This is an extension of the original WP. I burt restored MC1,3 to the hourly autoburt at 6am. Bypass times are now 21,600 (6 hours).

WP3577 DAQ Memory expansion. In h1dc0, h1nds0 and h1nds1 we replaced 6x2GB (12GB) DIMMS with 3x8GB(24GB). Went very smoothly.

WP3578 found that re-arranging the full height PCIE cards did indeed fix the problem of OAF,LSC,ASC causing dolphin crashes.

old new
Dolphin RFMX
RFMY RFMY
RFMX Dolphin
OneStop OneStop

Basically Dolphin and RFMX cards were swapped. This new PCIE arrangement means that power up of the computer does not crash all Dolphin'ed front ends, and RFM Card0=XArm Card1=YArm. h1lsc0's spectracom half height PCIE card was replaced, which fixed its timing problem. Second bad IRIG-B card so far.

WP3581, following the dismantling of the Newtonian Noise array at EY, we powered down h1pemauxey and h1tcsey and removed their channels from the CDS/DAQ systems. These were H2OAT systems and will not be ran for aLIGO.

h1susauxh34. We did a bit more investigation with this system. Its IOChassis was power-less, but DC power cord and front switch were GOOD and ON. Power cycle of front rocker switch powered the IOChassis back, but reboot of h1susauxh34 caused the IOChassis to de-power again. Interestingly the time from CPU restart to IOChassis power loss varied, and seems to be related to the cool down time of the IOChassis. We will investigate further.

h1isiitmy was now added to the DAQ following the mem upgrade, no problems.

h1susitmy was attempted to be added to the DAQ, but we exceeded a 120,000 channel limit (num fast chans + num slow chans + num testpoints). For now we are only storing the fast sus itmy channels and none of the slow sus itmy channels to keep below the limit (currently running with 117,137). LLO has increased this limit to 250,000 we are working on doing the same.

Jeff Kissel is building the burt safe.snap and filter files for SUS ITMY, based on ETMY.

H1 CDS
james.batch@LIGO.ORG - posted 13:48, Tuesday 27 November 2012 (4772)
Replace IRIG-B card in h1lsc0, shuffle RFM and Dolphin cards in h1lsc0, h1oaf0, and h1asc0
The IRIG-B card in the h1lsc0 computer has been bad since it was first powered up.  This has been replaced with a new card, timing is now correct.  

We previously discovered that powering up the h1lsc0, h1oaf0, or h1asc0 computers glitched the Dolphin network resulting in the need to restart all models on each computer connected to the Dolphin network.  To correct this, we took the opportunity to re-order the two RFM cards and Dolphin card on the PCIe riser to match the configuration of LLO computers.  Testing identified that the topmost RFM card shows up as RFM card 0 to an IOP model on the computer.  The card order for the full-height PCIe cards, top to bottom, is:

RFM-X (Card 0)
RFM-Y (Card 1)
Dolphin
One-Stop

Further testing shows that powering up the computer with the cards in this order does not glitch the Dolphin network.  This result was true for both h1lsc0 and h1oaf0.  The h1asc0 computer does not have an I/O chassis connected to it at this time, so power-up testing will take place later.  
H1 SUS
betsy.weaver@LIGO.ORG - posted 13:41, Tuesday 27 November 2012 - last comment - 07:11, Wednesday 28 November 2012(4771)
H1 ITMy is plugged into BSC1 and hangin'

I plugged in all 6 ITMy 25-pin connectors to the F3 feedthru flange on the BSC1 chamber.  Richard has been checking out the in-air connections/electronics.  Currently the PUM stage signals do not look healthy - he is chasing.  As well, Dave is making a burt restore file for this guy since he was blank - a copy/paste from the ETM.  Kissel is going to check it/tweek it later.

I've released the suspension so the speed dials should show normal swing and we can attempt damping as soon as everyone else is finished.  That said, SEI is heading back out to do trim masses upstairs this afternoon.

Comments related to this report
richard.mccarthy@LIGO.ORG - 07:11, Wednesday 28 November 2012 (4782)
The PUM stage was railing at -32000 counts so investigated the installation.  It appears that there is a subtle problem with the Satellite box for the PEM that is causing this.  I have swapped it out and the signals appear believable now.  The problem must be related to the -10 volt bias as the unit functions in photovoltaic mode but not in the A OSEM set up.
H1 PSL
michael.rodruck@LIGO.ORG - posted 11:44, Tuesday 27 November 2012 (4770)
PSL plots

For the 35W beam. There is a peak at 500Hz in the frequency spectrum that hasn't been there before and appears to have visible resonances.

Images attached to this report
Non-image files attached to this report
H1 SUS
jeffrey.kissel@LIGO.ORG - posted 07:42, Tuesday 27 November 2012 (4769)
Damped QUAD Model Finally Predicts Closed Loop TFs
A. Effler, J. Kissel, B. Shapiro

I've reconstructed the filters and gains that have been used to damp the H2/H1SUSETMY for the H2OAT, calibrating them with the appropriate signal chain gains in an attempt to finally merge models with measured reality. 

I attach two sets of plots.
(1) dampingfilters_H1SUSETMY_20121121.pdf: shows the filters, both in their raw uncalibrated (normalized) form (pg 1), as well as in their calibrated form (pg 2) using the EPICs gains that are currently in place.
(2) 2012-11-21_QUADDampedModel_Top2Top_TFs.pdf: shows a comparison between undamped and damped, model and measurement. The measurements used were taken from H1 SUS ETMY's Phase 3b results.

There is now excellent agreement with model and measurement for all degrees of freedom, most importantly with entirely understood frequency responses and gains. The remaining discrepancies arise from the differences in the undamped modeled plant and measured plant, namely the high frequency zero we believe to arise from drive and sensing chain cross coupling.

Now that model and measurement agree to such precision, we can now
- Explore compensation for the high-frequency zero
- See that this current set of filters and gains over damps most degrees of freedom, most likely reinjecting too much sensor noise into the system for a fully operational aLIGO IFO
- Accurately predict sensor and actuator noise at the test mass and design filters that will meet aLIGO requirements accordingly 
- Comfortably design hierarchical control filters which take into account realistic damping loops.

--------------------------------
Details:

Why we hadn't gotten here before today:
There were three pieces missing from the puzzle that had previously resulted in inaccurate models. 
(1) Prior to this update, the model had still been using legacy filters (in frequency response alone), and was using gains fudged by hand to get roughly the desired damping. This was "good enough" for the purposes needed to date, so we hadn't put much brain power into it. Perhaps more accurately I'd been previously stumped by the bug in the connection matrix described here, which is now fixed.
(2) The filter frequency response, along with using the actually-installed-EPICs gains, were were designed in foton "by hand." I've now exported and reproduced them in Matlab. The filters are calibrated into [N/m] or [N.m/rad] using the signal chain described briefly below (and in detail in LHO aLOG 4756 and LHO aLOG 4563). This calibration is needed because the model is (and has always been) calibrated in physical, SI units. The model of the closed loop is therefore

                                                             +--[m/N]--+
Ext. Forces -[N]-->(+)---------------[N]---------------------|  Plant  | ----------------[m]---------------------+-----> 
                    |                                        +[rad/N.m]+                                         |
                   [N]                                                                                          [m]
                    |   +-------------+              +----------+  +---------+                 +-------------+   |
                    +---|    Drive    |<--[drv. ct]--|EPICS GAIN|--|  DAMP   |<-(+)-[sns. ct]--|    Sense    |<--+
                        +-[N/drv. ct]-+              +-[ct/ct]--+  +-[ct/ct]-+   ^             +-[sns. ct/m]-+
                                                                                 |
                                                                                 +-- EXC

where the DAMP filter units, [ct/ct], are the designed, normalized frequency response. Note, 
- This reconstruction was done using the function
${SusSVN}/sus/trunk/QUAD/Common/FilterDesign/reconstructquadfotonfilters_20121121.m, where you can see the details of each filter design. I've saved the filters in the file
${SusSVN}/sus/trunk/QUAD/Common/FilterDesign/dampingfilters_QUAD_20121121.mat

- In practice, thanks to the powers of linear algebra, instead of treating the sensor chain (Sense) and actuator chain (Drive) independently, I merely multiply the normalized filters by the total DC gain of the signal chain,
 
              % <----------- Sensor Chain [sns. ct/m]------------>   <--- Actuator Chain [N/drv. ct] --->;
              %     OSEM                     SatAmp                              Coil Driver Coil/Magnet ;
              %  Sensitivity                TransImp.    ADC            DAC       TransCond. Force Coeff.;
              %(   [mm/uA]    [m/mm]  [uA/A]   [A/V]   [V/sens ct]   [drive ct/V]    [V/A]      [A/N]     )^-1= [(sns. ct/m) . (N/drv. ct)];
calibration = (( (0.7/76.29)*(1/1e3)*(1e6/1)*(1/240e3)*(40/2^16) ) * ( (2^18/20)*(1/0.009943)*(1/1.694) ))^-1;
            = 55.071 % [(sens ct/m) . (N/drive ct)] or [(sens ct/rad) . (N.m/drive ct)] 


(3) Previously, the damping filter's overall gain had been positive, and the feedback negative sign had been taken care of in the connection matrix, where the filters were hooked into the undamped state space model, in
${SusSVN}/sus/trunk/QUAD/Common/MatlabTools/QuadModel_Production/generate_QUAD_Model_Production.m.
Now that I'm using the actual EPICs gains, where the negative sign is explicitly called out, the sign in the connection matrix has been removed. I mention this only because it had stumped my for a day (let it be a less kids: always pay attention to the phase of your transfer functions!). Note this means all future filters input to generate_QUAD_Model_Production.m must have the overall sign be negative (regardless of whether it's included in the filter itself or explicitly in the EPICs gain).

These changes have been committed to the repository, with these 20121121 filters currently set as default; please svn up!
Non-image files attached to this report
LHO General
patrick.thomas@LIGO.ORG - posted 19:01, Monday 26 November 2012 (4768)
plots of dust counts
Attached are plots of dust counts > .3 microns and > .5 microns in particles per cubic foot from approximately 6 PM Nov. 25 to 6 PM Nov. 26. Also attached are plots of the modes to show when they were running/acquiring data.

The sensor may be failing on the dust monitor at location 2 in end Y. The local status was recorded in alarm a number of times today. It is not currently alarmed.
Non-image files attached to this report
LHO VE
kyle.ryan@LIGO.ORG - posted 17:04, Monday 26 November 2012 (4767)
Replaced CP7 dewar exhaust pressure regulator
CP7 dewar's vapor pressure value not responding to regulator adjustments -> fully closing (CW) adjustment screw has no effect -> fully opening (CCW) adjustment screw has no effect -> exhaust flow is continuous and not adjustable -> Closed manual valve which is in series with regulator to stop exhaust flow -> used heat gun to thaw exterior of regulator -> opened manual valve and fully closed and fully opened adjustment screw -> no change -> replaced regulator and left adjustment at 0 psi < factory setting < 30 psi -> manually filled CP7 to ~100% using LLCV bypass valve (resulted in CP7 alarm) 

Conclusion: Discovered upon disassembly of removed regulator that it was full of water.  This would have been ice with GN2 flow and explains why the adjustment was prevented as my thawing of the exterior wasn't enough to thaw the regulator's interior.  Otherwise the regulator was normal-no broken or worn-out parts.  The two threaded halves of the regulator assembly don't have and effective water seal between them.  When installed with the adjustment screw pointing up, as this one was, liquid water which condenses on the surface of the regulator during the summer months can enter the interior of the regulator and collect.  I will re-orient any regulators found to have their adjustment screws pointing up such that they point down.  

Expect CP7 alarms over the next day or two as the system comes into a new equilibrium and minor tweaks are made.
H1 SEI
eric.allwine@LIGO.ORG - posted 16:09, Monday 26 November 2012 (4766)
Four HEPI pump stations running
HEPI pump stations #5 and #6 have gone through the initial start up phase this afternoon and are now pumping 419-TY.  The pump servo set point is at 30psi to recirculate locally on the mezzanine driving pump stations #5, #6, #7, #8 at 20.5 HZ=615 rpm.  Pump stations #7 and #8 were started 1yr 3mo to 1yr 4mo ago.  
H1 AOS
david.barker@LIGO.ORG - posted 11:49, Monday 26 November 2012 (4765)
Extended IOP Watchdog bypass time for MC2 work

WP#3576

The IOP WD bypass time was extended from 10 mins to 6 hours for h1sush34 (MC2, PR2, SR2). This will permit mode cleaner commissioning which requires large DC offsets to be applied to MC2. This WP will remain open until the bypass time is restored to 10 mins.

H1 SEI
jim.warner@LIGO.ORG - posted 11:17, Monday 26 November 2012 (4764)
BSC1 ready for SUS work
GregG, JimW

After software issues were sorted last week, we were able to finish roughly balancing the ISI this morning. CPSes still need to be re-gapped and the balancing should be fine-tuned, but as of now the locked position is where it needs to be, after HEPI adjustments from last week, and the unlocked position is only a couple milli-inches off from that. The ISI was left locked, so SUS is clear to start their work.
LHO VE
kyle.ryan@LIGO.ORG - posted 18:34, Sunday 25 November 2012 (4762)
Adjusted CP7's dewar head pressure
Cycled instrument air to LLCV and verified that needle was 100% open as indicated by CDS -> Temporarily valved-in magnahelic differential gauge and confirmed CP7's level, 38" = 92% full -> Noted indicated vapor "head" pressure for LN2 dewar was low, ~5 psi -> No indication of parallel paths for vapor exhaust -> Adjusted exhaust pressure regulator 1/2 turn CW.
LHO VE
kyle.ryan@LIGO.ORG - posted 16:03, Sunday 25 November 2012 (4761)
Something amis with CP7
LLCV nominally 75% open to maintian CP7 level at setpoint -> Presently maxed-out at 100% -> Am monitoring indicate pump level -> may or may not investigate tonight 
LHO General
patrick.thomas@LIGO.ORG - posted 20:47, Wednesday 21 November 2012 (4760)
plots of dust counts
Attached are plots of dust counts > .3 microns and > .5 microns in particles per cubic foot from approximately 6 PM Nov. 20 to 6 PM Nov. 21. Also attached are plots of the modes to show when they were running/acquiring data.
Non-image files attached to this report
LHO VE
kyle.ryan@LIGO.ORG - posted 16:15, Wednesday 21 November 2012 (4759)
Isolated BSC6' annulus ion pump from rest of annulus plumbing @ ~1100? hrs local
Pump controller should have come on-scale by now if gas load was due to O-ring flanges (now isolated from pump) -> Swapped controller -> leaving pump valved-out -> leaving aux. cart pumping annulus (1.3 x 10-6 torr)
H1 SUS
jeffrey.kissel@LIGO.ORG - posted 12:10, Wednesday 21 November 2012 (4756)
H1 SUS ETMY M0 Phase 3b Transfer Functions
I've taken long-overdue damped and undamped, Phase 3b (with BSC6 at vacuum), transfer functions H1 SUS ITMY's main (M0) chain (formerly H2 SUS ETMY). Attached are the results: 2012-11-19 data is damped, and 2012-11-20 undamped. No surprises -- all mechanics look great / as expected. In processing these measurements, I've made improvements to the QUAD analysis scripts (see details below), so please svn up the QUAD corner of your local copies of the SusSVN. These were taken in-between Vincent's commissioning of BSC6-ISI, so I didn't press my luck to try and get reaction R0 chain measurements. We'll get 'em eventually.


Notes: 
- The damped transfer functions use the "final" set of filters and gains that were tuned / used during the H2 OAT, which look to be a little bit too aggressive, but it's a totally "by feel," qualitative assessment. With the newly fixed damped QUAD model, I intend to slap these filters and gains in (instead of the old "legacy" filters and arbitrary from LASTI which are in there now), and predict the test mass displacement -- specifically how much arises from sensor noise re-injected into the SUS vs. residual seismic noise. Stay tuned!

- The data was taken with freshly minted H1 SUS ETMY DTT templates, which can be found here:

/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMY/SAGM0/Data/
2012-11-19_1840_H1SUSETMY_M0_Mono_L_WhiteNoise.xml
2012-11-19_1840_H1SUSETMY_M0_Mono_P_WhiteNoise.xml
2012-11-19_1840_H1SUSETMY_M0_Mono_R_WhiteNoise.xml
2012-11-19_1840_H1SUSETMY_M0_Mono_T_WhiteNoise.xml
2012-11-19_1840_H1SUSETMY_M0_Mono_V_WhiteNoise.xml
2012-11-19_1840_H1SUSETMY_M0_Mono_Y_WhiteNoise.xml

(The same template is used for both damped and undamped transfer functions, so the date is the only thing one should need to change.)

- I've made several improvements to 

${SusSVN}/sus/trunk/QUAD/Common/MatlabTools/
plotquad_dtttfs.m
plotquad_matlabtfs.m
plotallquad_dtttfs.m
 
(1) I've added a few lines at the end of all three scripts which removes the individual plot .pdfs after they've been merged into the ALL.pdfs. They're just clogging up the svn, and were never use them anyways. 
For the "raw measurement" processing scripts, I've
(2) In the interest of getting all the gains right for predicting the damping loop performance, and because we now know the calibrations of the sensor and actuator chains well from independent measurements, I've changed the way the scripts calibrate the data. Namely, I explicitly calculate the [(sensor ct/drive ct) / (m/N)] (or [(sensor ct/drive ct) / (m/N.m)], [(sensor ct/drive ct) / (rad/N)], [(sensor ct/drive ct) / (rad/N.m)] as need be), instead of using the empirically measured value of 60. The number turns out to be 55.0708 [(sensor ct/drive ct) / (rad/N.m)], only an 8% difference, but it also aids in the understanding of improvement (3).
(3) I've added a switch inside the calibration step which -- based on a new, user-input, boolean, variable meas.sensCalib -- determines whether the OSEMINF "to_um" filter has been left ON during the measurement or not. Here's the new lines:

        if meas.sensCalib
                          % <-Sensor->   <---------- Actuator Chain ---------->;
                          %    OSEM                    Coil Driver Coil/Magnet ;
                          % Sensitivity       DAC       TransCond. Force Coeff.; 
                          %   [m/um]      [drive ct/V]    [V/A]      [A/N]   = [(m/um) . (drive ct/N)];
            calibration = (( (1/1e6) ) * ( (2^18/20)*(1/0.009943)*(1/1.694) ))^-1;
        else
                          % <----------------- Sensor Chain ---------------->    <--------- Actuator Chain --------->; 
                          %     OSEM                     SatAmp                              Coil Driver Coil/Magnet ;
                          %  Sensitivity                TransImp.    ADC            DAC       TransCond. Force Coeff.; 
                          %   [mm/uA]    [m/mm]  [uA/A]   [A/V]   [V/sens ct]   [drive ct/V]    [V/A]      [A/N]   = [(m/sens ct) . (drive ct/N)];
            calibration = (( (0.7/76.29)*(1/1e3)*(1e6/1)*(1/240e3)*(40/2^16) ) * ( (2^18/20)*(1/0.009943)*(1/1.694) ))^-1;
        end

Where, for the sensor chain, I've used the calibration as (best) described in LLO aLOG 4291, and for the drive chain, I've used the calibration as (best) described in LHO aLOG 4563 (though the force coefficient is different because HSTSs use 10Dx5T [mm] magnets, and QUADs, BSFMs, and HLTSs use 10Dx10T [mm] magnets on their top stage; the coil driver trans conductance is different because QUADs use QUAD TOP drivers, where HSTSs use Triple TOP drivers). Or, if you like pictures / diagrams, see T1100378. 

In case you're worried, we don't have to go back and re-run all of the old data. It's only an 8% change in the calibration, which we know can be less than the mechanical/electronics gain variation between suspensions. I will say though, I re-ran a few older measurements just to test it out, and it does put the measurements right smack on the model now for some of them (nice!).
Non-image files attached to this report
H1 SEI
jim.warner@LIGO.ORG - posted 11:55, Wednesday 21 November 2012 (4757)
BSC1 HEPI and ISI install progress
GregG, MitchR, JimW

Following the initial float of HEPI and Doug's follow up optical survey yesterday, HEPI was adjusted to fix the level of the the optical table this morning. The adjustment was relatively problem free, and the ISI is now level to within .1mm and is within .1 mm of the required elevation, at 244.1mm on Doug's ruler (see post 4752). After HEPI was adjusted, I locked the feet down while Greg and Mitch dropped cables down and plugged CPSes in. Unfortunately, a cable on a vertical sensor broke during install, so we will have to replace it, before proceeding with floating the ISI. We should be able to finish up by COB today, allowing SUSsers to resume work on Monday.
LHO General
patrick.thomas@LIGO.ORG - posted 09:26, Wednesday 21 November 2012 (4755)
plots of dust counts
Attached are plots of dust counts > .3 microns and > .5 microns in particles per cubic foot from approximately 6 PM Nov. 19 to 6 PM Nov. 20. Also attached are plots of the modes to show when they were running/acquiring data.

The plots of counts for the LVEA are missing. There were errors trying to plot them. They were not running for a time yesterday, (the power was unplugged, they probably glitched, and I didn't check for a while to see if they had come back). When they were being rebooted the channels for the calibrated counts were '-nan'. The edcu probably can not record this.
Non-image files attached to this report
LHO General
patrick.thomas@LIGO.ORG - posted 09:08, Wednesday 21 November 2012 (4743)
plots of dust counts
Attached are plots of dust counts > .3 microns and > .5 microns in particles per cubic foot from approximately 6 PM Nov. 18 to 6 PM Nov. 19. Also attached are plots of the modes to show when they were running/acquiring data.
Non-image files attached to this report
H1 IOO
cheryl.vorvick@LIGO.ORG - posted 00:54, Wednesday 21 November 2012 (4754)
Mode Cleaner alignment:
- Keita, Kiwamu, Cheryl


Mode Cleaner:
The beam is centered as it comes through MC1 and centered on MC2.  We were able to center the beam on MC3 using the alignment sliders on MC2.  The beam made it back around to MC1 and is separated from the input beam by about 1cm.  Then it was time to go home.

The alignment was made using irises placed on HAM2 and HAM3 according to the dimensions of alignment tools that Luke made.

One thing we ran into was that one OSEM on MC2 was basically railed, so the watchdog kept tripping.  When MC2 tripped, it moved mostly in yaw which suggests it might be bumping into an EQ stop.


Other work in HAM2:
The beam from the PSL had to be adjusted from inside the PSL, because the centering on the upper periscope mirror was off.  After centering on the upper periscope mirror, the periscope had to be rotated to align the beam to the lower periscope mirror.  The rotation was maybe 1-2 degrees.  The position and angle of AROM RH1 and ROM RH1 were adjusted.  The clamp on ROM RH1 was moved 180 degrees, after seeing that the screw in the clamp was at the far end of the slot, and after finding available space on the top level HAM2 layout drawing.
H1 SUS
jeffrey.kissel@LIGO.ORG - posted 14:55, Wednesday 31 October 2012 - last comment - 09:15, Monday 26 November 2012(4563)
H1 SUS PR2 Alignment Offsets Calibrated into [urads] of Optic Motion
Following a similar prescription as what Keiko's done at LLO (see e.g. LLO aLOG 4030), but now using the new infrastructure, I've installed a few gains,

H1:SUS-PR2_M1_OPTICALIGN_P_GAIN 2.636 [drive cts/urad]
H1:SUS-PR2_M1_OPTICALIGN_Y_GAIN 1.859 [drive cts/urad]

into the new OPTICALIGN bank, which should now be responsible for aligning the optic. With this gain, the offsets

H1:SUS-PR2_M1_OPTICALIGN_P_OFFSET (for Pitch)
H1:SUS-PR2_M1_OPTICALIGN_Y_OFFSET (for Yaw)

are then calibrated into [urad] of optic motion. This gain should be [applicable to / the same for] every HSTS.

I attach some shots of the new screens demonstrating where these gains live (and showing off the new screens).

-----------------------------
How the gain was calculated:
It's along signal chain, but here goes (I use Yaw on an HSTS as an example):
                                            
                                                                 LF  +--------+  +------+  +-----------+  +-----------+  +---------+  
                                                                  +->|COILOUTF|->| DAC  |->|Coil Driver|->|Coil/Magnet|->|Lever Arm|->+
+-----------------+  +---------------+  +----------+  +--------+  |  +[cts/ct]+  +[V/ct]+  +---[A/V]---+  +---[N/A]---+  +---[m]---+  |  +-------------+   +------------------+           
|OPTICALIGN OFFSET|->|OPTICALIGN GAIN|->|DRIVEALIGN|->|EUL2OSEM|->+                                                                   +->|HSTS M1 to M3|-->|Optic Displacement|
+-----[urad]------+  +---[cts/urad]--+  +-[cts/ct]-+  +[cts/ct]+  |  +--------+  +------+  +-----------+  +-----------+  +---------+  |  +--[rad/N.m]--+   +------[urad]------+
                                                                  +->|COILOUTF|->| DAC  |->|Coil Driver|->|Coil/Magnet|->|Lever Arm|->+
                                                                 RT  +[cts/ct]+  +[V/ct]+  +---[A/V]---+  +---[N/A]---+  +---[m]---+

(see fullsignalchain.png if you browser sucks at ASCII art)
Thankfully, because 
- we're only looking for the DC gain of this path, 
- the DRIVEALIGN matrix is an identity at this point
- the EUL2OSEM matrix accounts for (divides out) the number of actuators (two in this case) and the lever arm between the OSEM and the center of rotation
- the COILOUTFs are unity at DC
then our calculation only involves this simplified chain:

+-----------------+  +---------------+  +------+  +-----------+  +-----------+  +-------------+   +------------------+
|OPTICALIGN OFFSET|->|OPTICALIGN GAIN|->| DAC  |--|Coil Driver|--|Coil/Magnet|->|HSTS M1 to M3|-->|Optic Displacement|
+-----[urad]------+  +---[cts/urad]--+  +[V/ct]+  +---[A/V]---+  +-["N.m"/A]-+  +--[rad/N.m]--+   +------[urad]------+

(see reducedsignalchain.png if you browser sucks at ASCII art)
which means the OPTICALIGN GAIN is:

OPTICALIGN GAIN [cts/urad] = ( DAC [V/ct] * Coil Driver [A/V] * Coil/Magnet [N/A] * HSTS M1 to M3 [rad/N.m] * 1e6 [urad/rad] )^-1
                           = ( (20/2^18)  * 0.011919          * 0.963             * 0.4332 (for Yaw)        * 1e6            )^-1
                           = 1.850 [cts/urad]

The only difference for pitch is that HSTS M1 to M3 [rad/N.m] = 0.6172 (for Pitch). The electronics gains of the signal chain were taken from T1000061 (the contents of which have been experimentally confirmed elsewhere), and the HSTS M1 to M3 coefficients were taken from the production model (e.g. see T1200404).


                                                                  
                                                                 
Images attached to this report
Comments related to this report
jeffrey.kissel@LIGO.ORG - 09:15, Monday 26 November 2012 (4763)
S. Aston, J. Kissel

As with the QUAD (see LHO aLOG 4746), I have made mistakes in the OPTICALIGN gain calculation (shown above) in that, though the spelled out calculation is correct (with a "DC" compliance of 0.6172 [rad/N.m] (for Pitch), and  0.4332 [rad/N.m] (for Yaw)), the answer I call out has the values for Pitch and Yaw flipped. 

Even further, after double checking the DC compliance numbers using the HSTS model, I discovered that, for "DC," I used the value of the transfer function at 0.1 Hz. However, the transfer functions have not yet truly flattened by that point as the values at 0.01 Hz are:

M1 P to M3 P: 0.609 [rad/N.m]
M1 Y to M3 Y: 0.426 [rad/N.m]


Sheesh. I clearly did these calculations far too quickly, or at least was far too hasty with my copy-and-pasting. Thanks to Stuart for catching them!

So, redoing it slower, with the 0.01 Hz numbers for the "DC" compliance, the calculation should read:

(FOR AN HSTS)
OPTICALIGN GAIN [cts/urad] = ( DAC [V/ct] * Coil Driver [A/V] * Coil/Magnet [N/A] * HSTS M1 to M3 [rad/N.m] * 1e6 [urad/rad] )^-1
                           = ( (20/2^18)  * 0.011919          * 0.963             * 0.609 (for Pitch)       * 1e6            )^-1
                           = 1.8751 [cts/urad] (for Pitch)
OPTICALIGN GAIN [cts/urad] = ( DAC [V/ct] * Coil Driver [A/V] * Coil/Magnet [N/A] * HSTS M1 to M3 [rad/N.m] * 1e6 [urad/rad] )^-1
                           = ( (20/2^18)  * 0.011919          * 0.963             * 0.426 (for Yaw)         * 1e6            )^-1
                           = 2.6806 [cts/urad] (for Yaw)


As of this entry, I have corrected these gain values in H1 SUS PR2, saved a new h1suspr2_safe.snap, and committed it to the userapps repo,
/opt/rtcds/userapps/release/sus/h1/burtfiles/pr2/h1suspr2_safe.snap
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