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Reports until 15:46, Tuesday 06 December 2011
H2 DAQ
david.barker@LIGO.ORG - posted 15:46, Tuesday 06 December 2011 (1843)
EY front ends rebooted, h2sustmsy model has guardian part added

A glitch in the EY timing chain in the computer users room caused all EY frontends to glitch. I remotely power cycled the EY front ends, but managed to glitch the entire DAQ when rebooting h2seib6 (that is the only one which caused the glitch). Matt then made a change to the TMSY MASTER model to add the guardian part and we rebuilt and restarted h2sustmsy with the new model. The ini file was changed today, so we reverted back to the previous one sans the all-channels-as-comment-lines.

H2 SUS
jeffrey.kissel@LIGO.ORG - posted 15:23, Tuesday 06 December 2011 (1842)
BSC8 SUS Watchdog Levels
J. Garcia, J. Kissel

Now that we finally have a functional system with centered OSEMs at all stages for the H2 SUS ITMY and H2 SUS FMY, we've changed the watchdog values to be more stringent (as in actually protecting the system). See aLOG 1264 for details on the three types of watchdogs.
 
For all OSEM stages on both suspensions, we've set the limits as

OSEM DC LO: 100
OSEM DC HI: 30000

Justification: The DC watchdog watches the raw ADC inputs of the OSEMs. The possible range should be between 0 cts (when the flag is completely blocking the LED) and the open light current, close to the ADC limit of 32768. During normal operation, the OSEMs should be centered to around 15000 counts, and typically do not move +/- ~5000 from the centered position. However, at some point, adding a DC offset, or losing the bouyancy of the SUS in vacuum, (for example) may cause this center position to change. So, we pad the extremes a little bit, and go with the above values.


OSEM AC: 20000

Here, there's not too much experience with this value, but typical undamped RMS velocities are something around 1000 cts, and during drives something like 10000 cts. So, we'll continue to think about what a good value for this is.


ACTUATOR: 80000

Here the OSEMs don't have the drive strength to really do any damage, and we have a 18 bit DAC, so 120000 cts to play with. Typical levels for damped system are ~2000 cts, and for drive during transfer functions, around ~10000 cts.

Finally -- remember that the safest state for the suspension is to have damping loops ON. So we want the watchdog to trip only on super extreme cases. This is why it may seem we're being gracious with our thresholds.
H2 SUS
jeffrey.garcia@LIGO.ORG - posted 10:53, Tuesday 06 December 2011 - last comment - 19:13, Tuesday 06 December 2011(1840)
BSC8 FMy Troubleshooting
B. Bland
Reports from Garcia and Vincent from last night are that the FMy BOSEMs look unhealthy.  In fact, one of the satellite boxes is without power.  So, Richard is looking into why this is "broken". 
Comments related to this report
jeffrey.garcia@LIGO.ORG - 11:03, Tuesday 06 December 2011 (1841)
So, Richard restored power and we confirmed that the BOSEMs/cabling/power are healthy via the ADC Monitor channels.  However, the Speed dials are pretty messed up.  Not sure what mis-diagnosis took place last night, but I'm hoping someone played with the filters or model or something which now needs to be undone...?
jeffrey.garcia@LIGO.ORG - 19:13, Tuesday 06 December 2011 (1846)
The issue with the dial indicators was the input filtering that was enabled added an offset and has now been disabled.  Dial indicators are now roughly centered for the FMY M1 and M2 OSEMs. 
H2 SUS
jeffrey.kissel@LIGO.ORG - posted 08:34, Tuesday 06 December 2011 (1839)
H2 SUS ITMY (Mono) -- M0 (Main chain)
J. Garcia, J. Kissel

Jeff G.'s took a round a M0 transfer functions last Friday night, after the same changes:

- The BSC-ISI is floating!
- After all (er most?) of IAS adjustments have been made
- Stiffening elements have been put on
- Vibration absorbers have been put on
- L1 (UIM) and L2 (PUM) OSEMs have been aligned, and masses have been re-balanced accordingingly

It appears as though the F1 problems we were having, which raised all sorts of flags during the last set of measurments (2011-11-29), have continued to be less of a problem. To recap, the list was:
- The dynamics are different from the model, because the d's between the top stage and the UIM stage (parameters dn and d1) are not dead on. (yellow flag)
     Still true, but still only a yellow flag. It could (and most likely) just be that the model is incorrect d values from the "as built" suspension.
- The large offset in the UIM ballast mass (i.e. having it fully forward (HR side)), is causing that stage's horizontal center of mass to be offset from the center line of the suspension (represented by h1). (yellow flag)
     This cross coupling reduced from 2011-11-19 to 2011-11-29, and now is further reduced in the 2011-12-02 measurements. My guess is that whatever IAS work was done to get th test mass aligned in pitch, as well as what re-balancing had to be done after the L1 and L2 flags were installed helped move the center of mass back (or at least more) in-line with the center line of the suspension.
- The overall magnitude of the Pitch transfer functions are a ~50% lower than the model. (yellow flag) This may just be the accuracy of the measurement calibration factor.
       This also appears to be restored. Perhaps for the same alignment reasons as above
- There is an excessive amount of Longitudinal coupling into Pitch. This has been reduced with Travis flag dis- and re- assembly, but some cross coupling still remains. (red flag)
       Related to the second point, and again has reduced what may be negligible coupling.

HOWEVER, what *has* that has been steadily increasing is the cross-coupling of Longitudinal (the lowest modes) into Yaw. I will elevate this only to a yellow flag, because at that frequency, we only are taking data at a 0.01 Hz resolution, so there's a single data point. The data quality around these points is not awesome, so it could just be measurement noise on this data point. However, after looking at the phase comparison between F2 and F3 for these measurements (Yaw to Yaw drive), the two sensors for the past three measurements are in phase at that frequency, implying common mode motion between the two sensors -- i.e. longitudinal motion.
Non-image files attached to this report
LHO General
patrick.thomas@LIGO.ORG - posted 17:32, Monday 05 December 2011 (1837)
plots of dust counts
Attached are plots of dust counts > .5 microns.
Non-image files attached to this report
LHO VE
kyle.ryan@LIGO.ORG - posted 17:04, Monday 05 December 2011 (1836)
Vented Vertex and YBM
GV1 made uncharacteristic "clunk" at cam-over 

Purge air left isolated from vented volumes overnight
H2 SUS
jason.oberling@LIGO.ORG - posted 16:27, Monday 05 December 2011 (1835)
ITM Initial Alignment Progress
IAS: D. Cook, J. Oberling
SUS: B. Bland
 

We performed the final test stand alignments for the BSC08 Quad today.  Pitch was adjusted on the ITM and the ITM/CP gap was measured and the parallelism set.

This was the last of the test stand alignments.  The cartridge has now been handed off to the testers to complete required tests before the cartridge install.

H2 SEI
hugh.radkins@LIGO.ORG - posted 14:15, Monday 05 December 2011 (1834)
BSC8 ISI Refloating and balanced
After the primary Initial Alignment calcs, moves, adjustments had been made, Betsy removed many SUS or IAS things from the Optical Table this morning and handed it back to SEI.  We ended up adding 7-1/4kg (~16lbs) to Stage2 to re-balance.
Our lock/unlock motion is within specification so we hand the Cartridge Assembly back to SUS/IAS for final tweaking before testing.

Jim/Hugh
H2 SUS
jeffrey.kissel@LIGO.ORG - posted 12:02, Monday 05 December 2011 (1831)
H2 SUS ITMY (Mono) -- 2011-12-02 Results for R0 (reaction chain)
J. Garcia, J. Kissel

Jeff G.'s taken another round of measurements after the following:
- The BSC-ISI is floating!
- After all (er most?) of IAS adjustments have been made
- Stiffening elements have been put on
- Vibration absorbers have been put on
- L1 (UIM) and L2 (PUM) OSEMs have been aligned, and masses have been re-balanced accordingingly
Results look really good! More analysis to come, but I attached the results. This chain has had no where near as much trouble as the main chain; any problems that we did have were focused on the stiffness of the reaction cabling. It looks like what we have in place now has been consistent and like the model for the past two measurements. As long as nothing changes (other than locking and unlocking before and after the cartridge install) I approve this chain!@
Non-image files attached to this report
H1 PEM
patrick.thomas@LIGO.ORG - posted 10:17, Monday 05 December 2011 (1833)
H1 PSL dust monitor
I have removed the H1 PSL dust monitor and unplugged the external vacuum pump for it in the mechanical room.
H1 SEI
greg.grabeel@LIGO.ORG - posted 10:01, Monday 05 December 2011 (1832)
Fixing a horizontal GS-13
Non-final podded seismometers were being used for testing on our completed HAM assembly. Last week a horizontal unit wasn't functioning correctly, it would respond to large inputs but damp very quickly. I thought this would most likely be caused by a mass that was uncentered. Luckily for us this particular seismometer was going back to Livingston anyway, so Vincent and I popped the vacuum pod and removed the GS-13. While doing this I noticed the crossbar on one edge was noticeably looser than the others and was most likely due to a kinematic foot backing up the threaded rod. This tilt would be enough to rail the seismometer's mass.

While the can was off the base plate Vincent and I double checked the flexures to see if any of them had loosened or broken, but they were all in good shape. Since we don't have an angle bracket to re-level the horizontal GS-13s to the base plate I hoped that the top of the seismometer was perpendicular enough to the mass to level from that. With the GS-13 back on the base plate and a precision level on top of the GS-13 I adjusted the kinematic feet to obtain a level (again hopefully perpendicular) within 80-90 seconds. Then I locked down the jam nuts and hand tightened the crossbars. After sealing the top hat back onto the base plate I realized I probably should have taken pictures, then I freaked out and wondered if I unlocked the mass. After reinstalling the pod onto HAM 1 Vincent checked the refurbished GS-13's frequency response to the others and everything looked good.

This definitely seemed to be an issue with either a loose jam nut or an insufficiently tightened crossbar. These testing seismometers saw quite a bit of abuse with how much they had been removed and reinstalled but extra care should be paid attention to these feet as having to deal with a bad GS-13 in vacuum will be a significantly larger headache.
Images attached to this report
H2 SUS
jeffrey.kissel@LIGO.ORG - posted 09:33, Monday 05 December 2011 (1809)
H2 SUS ITMY (Mono) -- M0 Cross Coupling Reduced, still not awesome
J. Kissel, B. Shapiro, J. Garcia

After some mechanical adjustments on H2 SUS ITMY M0 made by the assembly team, 

- F1 flag dis- and re- assembly at TOP stage
- Moving mass forward on UIM
- Recovering UIM and PUM signals, aligning flags,

Jeff G. has taken another set of transfer functions to asses how we did (Last Tuesday, 2011-11-29). In summary, the main chain looks better (but still not great -- Pitch as usual) but not as good as we'd like. We believe there are several issues going on:
- The dynamics are different from the model, because the d's between the top stage and the UIM stage (parameters dn and d1) are not dead on. (yellow flag)
- The large offset in the UIM ballast mass (i.e. having it fully forward (HR side)), is causing that stage's horizontal center of mass to be offset from the center line of the suspension (represented by h1). (yellow flag)
- The overall magnitude of the Pitch transfer functions are a ~50% lower than the model. (yellow flag) This may just be the accuracy of the measurement calibration factor.
- There is an excessive amount of Longitudinal coupling into Pitch. This has been reduced with Travis flag dis- and re- assembly, but some cross coupling still remains. (red flag)

I attached four plots for your perusal. All are M0 TOP to TOP transfer functions.
(1)allquads_111130_H2SUSITMY_ALLM0_TFs.pdf 
Comparison between nominal model (BLUE) previous main chain measurements (ORANGE), and current main chain measurements (BLACK). Note that 2011-11-19 measurements of V and R are missing, because the M0RT OSEM had failed. We see hear, as before, that the degrees of freedom (besides Pitch) all line up quite well with the model, implying that the majority of the dynamics in the suspension are free and well. 
(2)2011-11-29v2011-11-19_H2SUSITMY_M0_P-P_TF.pdf 
Zoom Comparison between nominal Fiber model, the first 2011-11-19 measurement, and the current 2011-11-29 measurement. Here, we see the good news that the severe cross-coupling between L and P has been reduced, but not to what we expect from the model (and from what we've seen on metal builds).
(3)2011-11-29v2011-11-19_H2SUSITMY_M0_P-L_TF.pdf 
Model, 2011-11-29, and 2011-11-19 Pitch to Longitudinal cross coupling (compared against 2011-11-29 and 2011-11-19 Pitch to Pitch), quantifying the reduction.
(4)2011-11-29v2011-11-19_H2SUSITMY_M0_P-P_TF_modelcomp.pdf 
Comparison between models with parameters varied, in order to try to explain what might be happening with the dynamics and the yellow flags mentioned above. I've tried moving around two parameters that we believe might effect the dynamics as we've seen (motivated by physical differences). 

     fiber = Nominal Model, with h1 = 0 mm, and both dn and d1 = 1 mm
     fiber_h1plus5mm = Modified model, with h1 = +5 mm
     fiber_dnd1plus1mm = Modified model, with dn and d1 = 2 mm (break off points are further away from the vertical center of mass, dn increased in +Z, d1 is increased in -Z)
     fiber_fiber_h15mm_dnd11mm = Modified model, with both h1 = +5mm, and dn=d1=2mm

Again, we suspect that h1 is offset because there's a good fraction of the ballast mass on the HR side of the UIM, and we suspect the d's concerning the UIM might be off, because they (a) affect the two modes that are the most different in the model, and (b) these d's are adjustable, and are defined by blade tip heights a physical parameter difficult to mail down. One can see that, though both parameters effect the dynamics differently, the combination of the two explain the measurement quite well, specifically offsetting the horizontal center of mass at the UIM explains some of the high-frequency cross-coupled length resonances.

-----------------------

Our best guess up to this point as to where the remaining cross-coupling is originating from is that F1 is not driving as much as we think. The idea being that we intend drive equally in (F2+F3) and F1, and because either the F1 (a) electronics, or (b) the OSEM coil-magnet pair results in less drive in F1, there is an imbalance in the drive, and (F2+F3) ends up driving more, which means that Length is excited more than expected.

Things I'm looking into in order investigate this claim:
- Looking at F1 response in a Length drive, compared against models. The thought is perhaps the monolithic is more susceptible to this particular flaw, so comparisons against metal builds may not be as enlightening, but we can check anyways. If there's a large discrepancy, this would indicate that the sensing part of the OSEM is at fault.
- Comparing Pitch / F1 response to reaction chains. The TOP and UIM masses are identical between the two chains, and should therefore have the same mass. Further, the total mass of the two chains is identical. This means at high frequency, above the resonances, where the transfer function should be just as a free mass (F = m a, or T = I a), the chains should be the same.

Measurements we can do in order to better identify the problem
- Measure the OSEM basis (F1 to F1, F2 to F2, etc) transfer functions, and compare against the model (~2 hours of measurement, 1 days worth of analysis). If the F1 to L check doesn't turn up anything, then if this comparison with model shows something strange, then we know it's the actuator side of the OSEM that's failing.
- Measure the F1 response at DC (at a few different drive levels, using offsets in the COILOUTF banks), then replace the OSEM with a new OSEM from "off the shelf," and perform the same measurement. (1/2-a-day of measurement, 1/2-a-day of analysis) If there's any change, you know it was the bad OSEM. If there's no change, then we know the OSEM coil-magnet pair is OK, and it's some further flaw upstream in the electronics. 
- If the OSEM turns out not to the be the problem, we can drive equal amounts of digital signal from the DAC, and measure the response at the mock in-vacuum feedthrough. (1/2-a-day of measurement, 1/2-a-day of analysis).
Non-image files attached to this report
H2 SEI
hugh.radkins@LIGO.ORG - posted 09:20, Monday 05 December 2011 (1830)
HAM ISI rebuilding On-Going in Staging Building
Couple Photos and brief report here.

First, the ISI is carefully placed back on the Test Stand.  The second photo shows the rebuilt Stage1 back on the Stage0.

The HAM 9 unit is currently undergoing testing.  The HAM8 unit (shown in these photos) will have its Springs pulled down today quickly followed by the installation of the Optical Table.

Jim, Corey, Mitchell, Greg, Eric, & Hugh
Images attached to this report
H2 SUS
jeffrey.garcia@LIGO.ORG - posted 17:40, Sunday 04 December 2011 (1829)
M0 and R0 OSEM Coil Output Filter gains
The H2:SUS-ITMY_*_COILOUTF_*_GAIN channels were modified on the R0 chain such that a positive drive from the Euler-basis coil outputs induced a positive response in the Euler-basis H2:SUS-ITMY_*_DAMP_*_IN1_DQ OSEM readback channels.

For the H2:SUS-ITMY_M0_COILOUTF_*_GAIN channels:
F1 = 1.0
F2 = 1.0
F3 = -1.0
LF = -1.0
RT = 1.0
SD = -1.0

For the H2:SUS-ITMY_R0_COILOUTF_*_GAIN channels:
F1 = 1.0
F2 = 1.0
F3 = -1.0
LF = 1.0
RT = -1.0
SD = -1.0
H2 SUS
jason.oberling@LIGO.ORG - posted 15:52, Sunday 04 December 2011 (1828)
ITM Test Stand Alignment Progress

Found the 6.7mm error this morning.  The error was not in the EDM measurement, but in the design of the corner cube mount.  As the mount is currently designed, we touch off of a metal plate that is sandwiched between the corner cube and the XY translation stage of the mount with a CMM to accurately measure the distance between this metal plate and the ITM; this gives us the distance we need to add to the EDM measurement to get the total distance from the total station to the ITM (the EDM from the total station only measures to the corner cube).  This plate was thought to be at the back plane of the corner cube (most corner cubes have a constant that is the offset distance from the virtual focus of the coner cube to its back plane and this distance must be compensated for when using a corner cube for EDM; our corner cube has a 30mm constant) but in actuality the back plane of the corner cube is 10mm inside the metal plate.  This subtracted 10mm from the measured distance, indicating that the structure had to be moved in the -y direction.  We will start considering a redesign of the corner cube mount, but in the short term we were able to compensate for this using the total station.  The total station has the ability to automatically compensate for a corner cube constant, therefore we simply changed the constant from the 30mm we were using (since it was a 30mm prism constant) to 20mm, which represents the distance from the coner cube virtual focus to the front surface of the metal plate.  This also means that the FM, which was thought to have been 12.7mm too far forward, is only 2.7mm off of its ideal longitudinal position, which is within the ±3mm of error set out in E1100690.

Since the quad had been clamped to the table, we decided to take all the ITM pointing measurements again:

As a result of today's work, we determined that no more structure moves are necessary and we can continue with the fine pitch and yaw alignments.

LHO General
kyle.ryan@LIGO.ORG - posted 13:01, Sunday 04 December 2011 (1827)
Drove to Y-end, past West Bay of Corner Station @ 1234 and 1251 hrs. local (logged for Doug and crew)
Signage at LVEA card reader requested noise source logging 
H2 SUS
betsy.weaver@LIGO.ORG - posted 22:39, Saturday 03 December 2011 (1826)
BSC8 SUS Work
Because I don't see a current a log, I'm posting what I know for today. On Friday afternoon we completed adding the balance of the SUS payload to the ISI table.  The SEI crew then balanced the table but left it locked so we could make a round of Romer arm measurements on the ITMy.  Still hunting for the ~6mm y-axis error, we made some measurements of the upper structure structure relative to the ITMy HR surface.  We have had some manufacture errors with these upper structures, so we wondered if there were more that we had not found.  At first glance, based on these measurements, the suspension position within the structure does not seem to be the source of our error.  The ISI was unlocked and the suspensions unclamped for the night.  I believe Garcia and Vincent were going to start testing the systems but I'm not sure their status.  
Today, Dennis continued the 6mm hunt by looking at our alignment templates which were used when fixing the ITMy to the table.  These do not appear to be the source either. As of discussions this afternoon Dennis, Doug, and Jason anticipate working tomorrow morning to redo the EDM measurements.
H2 AOS
matthew.evans@LIGO.ORG - posted 20:11, Saturday 03 December 2011 (1825)
TMSY suspension damping and plant measurements

Bram, Valera, Matt

We made a few measurements of TMSY and got some damping loops running.  The attached plots show:

  1.  damping performance (REF plots are damping on)
  2. screen shot showing filters and gains
  3. plot of the damping filter used for all DOFs
  4. damping open-loop TF and plant TF for each DOF

We've left the damping loops on for a few days and they appear to be working well.

Images attached to this report
H2 SUS
jeffrey.garcia@LIGO.ORG - posted 15:49, Friday 02 December 2011 (1824)
H2 ITMY now with full payload onto BSC-ISI
This morning, the SUS crew added the remaining mass to the H2 ITMY QUAD structure by adding the stiffening sleeve with vibration absorbers.  The seismic crew has now balanced the ISI with the full ITMY and FMY structures.  The BSC-ISI is now locked so that Romer arm measurements can begin on the ITMY QUAD and Test Mass. The afternoon's goal is to have the BSC-ISI floating with the H2 ITMY fully suspended and OSEM flags to center-range.
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