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ID Date Author Type Categoryup Subject
  4596   Mon May 2 13:30:13 2011 kiwamuUpdateSUSPRMI locking prep: PRM oplev

I had a quick look at PRM optical lever.

The He-Ne beam is still successfully coming out from the chamber and I could guide it to the QPD by using steering mirrors.

But the beam size looks too big for the QPD. We should slide the lens which is standing before the injection to get a moderately smaller beam size at the QPD.

Quote from #4595

 - activation of PRM oplev

  4599   Mon May 2 17:10:55 2011 steveUpdateSUSPRM oplev

The returning spot diameter on the qpd ~10 mm. In order to reduce the spot size I moved the f 1145 mm lens toward the PRM ~ 25 cm. The spot size was reduced to ~8 mm, 3200 counts.

I'll try to find an other lens tomorrow.

  4611   Tue May 3 13:22:13 2011 LeoUpdateSUSRe: DRMI prep : suspension diagnostic

Here are the free-swinging spectra for the BS, ETMX, ETMY, ITMX, ITMY, MC1, MC2, MC3, and PRM chambers.  Kiwamu left the suspensions free for 5 hours this weekend, starting at Sat Apr 30 00:15:26 2011.

This is GPS time 988 182 941.  Quick tip: you can do local to GPS time conversions using lalapps_tconvert, which is a lot like tconvert but with special powers.  It is installed on pianosa.

$ lalapps_tconvert Sat Apr 30 00:15:26 2011

988182941

I generated these figures with the attached Python script, measure.py.

Notice that the C1:SUS-ITMX_SENSOR_UL and C1:SUS-MC3_SENSOR_UL spectra fall as 1/f.  Jenne suggested that this might indicate that there is a loose electrical connection.

Also, notice that C1:SUS-ETMY_SENSOR_LR, C1:SUS-ITMY_SENSOR_LL, and C1:SUS-PRM_SENSOR_SIDE are a lot noisier above 10 Hz.

  4613   Tue May 3 15:04:20 2011 kiwamuUpdateSUSRe: DRMI prep : suspension diagnostic

Jenne went through all the suspension racks and pushed all the connectors.

After pushing them, we had a quick look at those spectra and found no funny noise spectrum except for C1:PRM-SENSOR_UL.

We then checked connection around the SCSI cables and eventually found the connection between ADC_card_0 and a SCSI was loose.

We put short standoffs on the ADC card so that the screws from the SCSI can nicely reach to the ADC card. Now everything looks fine.

SUS diagnostic is quite useful !

Quote from #4611

Notice that the C1:SUS-ITMX_SENSOR_UL and C1:SUS-MC3_SENSOR_UL spectra fall as 1/f.  Jenne suggested that this might indicate that there is a loose electrical connection.

  4616   Tue May 3 16:20:13 2011 steveUpdateSUSPRM & BS oplevs are ready

Quote:

The returning spot diameter on the qpd ~10 mm. In order to reduce the spot size I moved the f 1145 mm lens toward the PRM ~ 25 cm. The spot size was reduced to ~8 mm, 3200 counts.

I'll try to find an other lens tomorrow.

 Atm 1,  PRM oplev inward path with 2 lens solution: 14 cm gap between F 1145 and F 1545 mm lenses. 

Atm 2,   The PRM beam size 3 mm and the beam  quality is still bad. The BS path only needed alignment.

  4626   Wed May 4 13:57:04 2011 kiwamuUpdateSUSmechanical resonances updated

[Leo  w/ a little help from Kiwamu]

Leo summarized the mechanical resonances of all the suspensions, based on the free-swinging spectra taken on Sat Apr 30.

Since Leo doesn't have the wiki account I helped him putting the information on the wiki.

Good work, Leo !

http://blue.ligo-wa.caltech.edu:8000/40m/Mechanical_Resonances

Quote from

Here are the free-swinging spectra for the BS, ETMX, ETMY, ITMX, ITMY, MC1, MC2, MC3, and PRM chambers.  Kiwamu left the suspensions free for 5 hours this weekend, starting at Sat Apr 30 00:15:26 2011.

 

  4646   Thu May 5 17:19:21 2011 Leo SingerConfigurationSUSTuning notch filters for bounce mode suspensions

I am tuning the notch filters for the bounce modes in the suspensions, starting with the ITMs and ETMs.  I'll do the MCs, the PRMs, and the SRMs next.

 

I noticed that the filter for ITMX (in the file C1SUS.txt, the module ITMX_SUSPOS, the selection BounceRoll) that the filter was composed of two bandstops (and a constant gain).  It looked like this:

 

ellip("BandStop",4,1,40,11.4,12.2)ellip("BandStop",4,1,40,16.7,17.5)gain(1.25872)

 

Valera said that one of these was for the roll mode and the other for the bounce mode.  However, looking at the spectra that Kiwamu and I made this week, I don't perceive a resonance between 11.4 and 12.2 Hz.  So, we're taking a guess that this was for a mode that has moved due to new pendulum designs.  For many of the suspensions, in the free swinging test we noticed a line around 23 Hz; we thought we might as well re-use one of these elliptical filters to avoid exciting this line.  Of course, if this line does *not* result from excitation of an uncontrolled degree of freedom, this will not help and could be detrimental.  When we talk to Valera again, we can review this decision and at that point we might decide just to take out that bandstop.

 

ITMX is done.  I'll continue tomorrow.  I've attached closed-loop spectra for before the tuning (itmx-before.pdf) and after (itmx-after.pdf).

 

(Update: the following day, I took closed loop spectra with (itmx-withbounceroll.pdf) and without (itmx-nobounceroll.pdf) the bandstops.  It looks like the bandstops made the bounce mode slightly worse, but the roll mode slightly better.)

 

 

  4652   Fri May 6 14:59:36 2011 Leo SingerConfigurationSUSTuning ITMY bandstop

I tuned the ITMY bandstops -- 'before' and 'after' spectra attached.  Note that the after the tuning, the bounce mode at ~16 Hz is about twice as quiet!

 

However, notice that in the 'before' plot the roll mode at about 23.5 Hz did not show up at all, whereas it is quite prominent in the 'after' plot.  I was concerned that this line could have been a result of placing the bandstop there, so I made another plot with the BounceRoll filter turned off.  Sure enough, the 23.5 Hz line is still there.  So I'm not crazy: the roll mode did start acting up at some time between my 'before' and 'after' plot, but not as a result of the tuning.

  4655   Fri May 6 17:11:55 2011 steveUpdateSUSSRM-oplev cable

The SRM qpd cable was removed from the BS-table. It's path was changed from 1x4 to ITMY-table following the inner cable tray.

  4682   Tue May 10 22:56:17 2011 kiwamuUpdateSUSf2p filters installed on ETMY

New f2p filters were installed on ETMY. 

The statistical error of the coil gain settings are now about 0.8% at high frequency (i.e. above the resonant freq of the pendulum mode)

 What I did :

 -   measured and corrected the coil imbalances on ETMY using a script called F2P_LOCKIN.py

 -   made the new f2p filters based on the measurements and installed them.

  Next step :

 -  do the same adjustment for all the suspensions including PRM, SRM, BS, ITMs and ETMs

 


(Notes on F2P_LOCKIN.py)

 F2P_LOCKIN.py is a script that I've made in python. This is basically the same as the old script, f2pratio, but uses the realtime LOCKINs instead of ezcademods.

The script automatically measures the coil imbalances on an optics of interest by driving the local LOCKIN oscillators.

In the first step the script automatically balances the coil gains at high frequency (8.5Hz).

In the next step it gives some coefficients, which basically represent the coil imbalances at low frequency (0.01Hz)

Then with those coefficients one will be able to design the f2p filters.

It is not well polished yet, so I will spend some more times to make it user-friendly and readable.

Example usage : F2P_LCKIN.py -o ETMX

It currently resides in /cvs/cds/rtcds/caltech/c1/scriptss/SUS/

 

(new f2p filters)

The plot below shows the new f2p filters. Note that they are already installed.

f2p_etmy.png

Pendulum mode = 0.982 Hz (according to the wiki)
Q of the pendulum mode = 1 (to avoid ringing of IIR filters)
C1:SUS-ETMY_ULCOIL_GAIN = -0.793435
C1:SUS-ETMY_URCOIL_GAIN = 1.16877
C1:SUS-ETMY_LLCOIL_GAIN = 1.25028
C1:SUS-ETMY_LRCOIL_GAIN = -0.730704
UL_fz = 0.965125
UR_fz = 1.029517
LL_fz = 0.934231
LR_fz = 0.996562
UL_Qz = 0.982816
UR_Qz = 1.048388
LL_Qz = 0.951356
LR_Qz = 1.014829
  4683   Tue May 10 23:14:01 2011 kiwamuUpdateSUSETMX_OPLEV : He-Ne laser dead ?

I found that a He-Ne laser which has been used for ETMX_OPLEV was NOT giving the light.

Since I didn't find the switch key for it I have no idea if the laser is simply off or dead.

  4686   Wed May 11 11:05:45 2011 steveUpdateSUSETMX_OPLEV : He-Ne replaced

Quote:

I found that a He-Ne laser which has been used for ETMX_OPLEV was NOT giving the light.

Since I didn't find the switch key for it I have no idea if the laser is simply off or dead.

 The dead laser was replaced by new JDSU 1103P of  2.6mW. The return beam is big ~5 mm diameter of 0.3 mW,  1400 counts

  4687   Wed May 11 11:24:59 2011 steveUpdateSUSSRM-oplev qpd is back

Quote:

The SRM qpd cable was removed from the BS-table. It's path was changed from 1x4 to ITMY-table following the inner cable tray.

 Laser diode oplev SRM is working. Qpd matrix values were reset like others.

In 0.44mW, returning 0.1mW,  -500 counts.

  4688   Wed May 11 11:44:52 2011 kiwamuUpdateSUSf2p filters installed on ITMY

New f2p filters were installed on ITMY this morning. The statistical error of the coil gain setttigs are about 0.6 % at high frequency.

NEXT : PRM, SRM, BS, ITMX and ETMX.

 

f2p_itmy.png

 Pendulum mode = 0.988 Hz, Q = 1

C1:SUS-ITMY_ULCOIL_GAIN = 1.02482

C1:SUS-ITMY_URCOIL_GAIN = -1.06831

C1:SUS-ITMY_LLCOIL_GAIN = -0.996671

C1:SUS-ITMY_LRCOIL_GAIN = 0.91079

UL: fz = 1.014824 Hz, Q = 1.027150

UR: fz = 0.975038 Hz, Q = 0.98688

LL: fz = 1.000229 Hz, Q = 1.012378

LR: fz = 0.972688 Hz, Q = 0.946116

Quote from #4682

New f2p filters were installed on ETMY. 

The coil imbalances are now about 0.8% at high frequency (i.e. above the resonant freq of the pendulum mode)

  4693   Wed May 11 21:58:30 2011 ranaUpdateSUSETMX_OPLEV : He-Ne replaced

Quote:

Quote:

I found that a He-Ne laser which has been used for ETMX_OPLEV was NOT giving the light.

Since I didn't find the switch key for it I have no idea if the laser is simply off or dead.

 The dead laser was replaced by new JDSU 1104P of  2.6mW. The return beam is big ~5 mm diameter of 0.3 mW,  1400 counts

 Whenever replacing any Oplev laser, please also put into the ELOG when it was installed so that we have an electronic record of the laser lifetime.

  4713   Fri May 13 17:20:48 2011 Leo SingerConfigurationSUSTuned bounce and roll mode of ETMY suspension

I tuned the bounce and roll mode bandstops for ETMY, although it was difficult for me to tell if there was improvement with the bandstops on relative to the bandstops off because it seemed like the bounce and roll modes were being excited intermittently.  I'll take spectra with the filters both on and off during an evening next week.

  4719   Sun May 15 12:42:29 2011 kiwamuUpdateSUSf2p ratio adjutment done for all the suspensions

The f2p adjustment for all the suspensions are done (except for MC1,2,3)

  4731   Tue May 17 16:53:22 2011 kiwamuUpdateSUSoplev sign was wrong on ETMY

Last night I found that the sign of the oplev control of PITCH on ETMY was wrong. I flipped it to the correct sign.

We've been locking the Y arm by feeding a signal back to ITMY  because pushing ETMY somehow made the lock unstable in the angular motion.

After the correction of the oplev contol sign, I was able to keep the lock robustly by pushing ETMY.

  4734   Tue May 17 19:38:32 2011 kiwamuUpdateSUSwrong connection on 1X5

Today Steve was working around the 1X5 rack to strain relief the cable jungles and the jungle is now getting less jungle.

During the work he disconnected and reconnected some cables.

So for a doublecheck I checked all the suspensions to see if the suspensions are still healthy or not.

Aha, then I found a mistake.

 

See the pictures below. It's a very subtle difference. This wrong connection prevented MC1 and MC3 from damping.

wrong.png correct.png

  4752   Fri May 20 01:02:50 2011 loose connection hunterUpdateSUSloose connection on ETMY rack

The UL signal of the shadow sensor on ETMY went to zero this evening.

This was due to a loose connection on the cross connection board on the 1Y4 rack.

In order to make them tighten, a combination of stand-offs and screws were installed on the connectors. They won't be loose any more.

ETMY_loose.png

  4775   Tue May 31 17:30:42 2011 steveUpdateSUSETMY damping restored

ETMY's watch dogs were found tripped. They were restored.

  4780   Thu Jun 2 16:23:42 2011 JamieUpdateSUSSUS control models updated to use new sus_single_control library part

A new library part was made for the single suspension controller (it was originally made from the c1scx controller), using the following procedure:

  1. Opened c1scx model (userapps/trunk/sus/c1/models/c1scx)
  2. Cut ETMX subsystem block out of SUS subsystem
  3. Pasted ETMX block into new empty library, and renamed it C1_SUS_SINGLE_CONTROL
  4. Tweaked names of inputs, and generally cleaned up internals (cosmetically)
  5. Saved library to: userapps/trunk/sus/c1/models/lib/sus_single_control.mdl

Once the new sus_single_control library part was made and the library was committed to the cds_user_apps repo, I replaced all sus controller subsystems with this new part, in:

  • c1scx
  • c1scy
  • c1sus (x5 for each vertex mass)

All models were rebuild, installed, and tested, and everything seems to be working fine.

  4791   Mon Jun 6 22:41:22 2011 ranaUpdateSUSSwitching problem in SUS models

Some weeks ago, Joe, Jamie, and I reworked the ETMY controls.

Today we found that the model rebuilds and BURT restores have conspired to put the SUS damping into a bad state.

1) The FM1 files in the XXSEN modules should switch the analog shadow sensor whitening. I found today that, at least on ETMY and ETMX, they do nothing. This needs to be fixed before we can use the suspensions.

2) I found all of the 3:30 and cts2um buttons OFF AGAIN. There's something certainly wrong with the way the models are being built or BURTed. All of our suspension tuning work is being lost as a consequence. We (Joe and Jamie) need to learn to use CONLOG and check that the system is not in a nonsense state after rebuilds. Just because the monitors have lights and the MEDM values are fluctuating doesn't mean that "ITS WORKING". As a rule, when someone says "it seems to work", that basically means that they have no idea if anything is working.

3) We need a way to test that the CDS system is working...

  4792   Mon Jun 6 23:56:16 2011 rana, valeraConfigurationSUSETMX/ETMY OSEM whitening

 We measured the OSEM PD whitening transfer function of the ETMX OSEM UL whitening stage (D000210) by comparing the input signal to the whitening amplifier (single pin LEMO monitor) to the output signal - both were piped into the DAQ. The transfer function was close to constant 0 dB/180 deg independent of the whitening switch selection (FM1 filter engaged/disengaged)  up to ~20 Hz where we run out of coherence. All other ETMX and ETMY spectra at the input of the digital whitening compensation don't change when the whitening is switched on/off so by induction we conclude that all the ETMX/ETMY OSEM PD hardware whitening filters are not on.

  4793   Tue Jun 7 11:39:27 2011 JamieUpdateSUSNo binary output module in ETMY
Quote:

1) The FM1 files in the XXSEN modules should switch the analog shadow sensor whitening. I found today that, at least on ETMY and ETMX, they do nothing. This needs to be fixed before we can use the suspensions.

Joe discovered today that ETMY in fact has no binary output module at all, so there is actually no digital control of the whitening filters at ETMY.

We suspect that the ETMY binary output module was maybe harvested to put in the LSC rack, but we're not sure.

We found a spare binary output adapter pcb, which I will try to assemble into a module to install in ETMY.

This does not explain what's going on with ETMX, though.  ETMX has a binary output module, that appears to be properly hooked up.  I'll try to debug what's going on there as well.

In the mean time, I've removed the ETMX binary output module to use as a reference for putting together another identical module for ETMY.

  4802   Thu Jun 9 20:10:38 2011 kiwamuUpdateSUSETMY whitening filter : all off

I checked the state of the whitening filters for the ETMY shadow sensors.

Result : They've been OFF  (i.e. flat response).

 

(measurement and setup)

 I measured the transfer functions of the whitening board (D000210) by looking at the signal before and after the whitening stage.

 The whitening board handles five signals; UL, UR, LR, LL and SD, and there are five single-pin lemo outputs for each signal on the front panel.

A good thing on those lemo monitors is that their signals are monitored before the whitening stages.

Rana suggested me to use these signals for the denominator of the transfer functions and consider the sensor signals as excitation signals.

So I plugged those signals into extra ADC channels via an AA-board and measured the transfer functions.

In the measurement the coherence above 4 Hz was quite small while the suspension was freely swinging.

Therefore I had to excite the ETMY suspension by putting random noise in a frequency band from 5 Hz to 35 Hz to obtain better coherence.

 

(results)

 The response is flat over frequency range from ~ 0.2 Hz to ~40 Hz, see the plot below. 

According to the spectrum of each signal the measurements above 10 Hz are just disturbed by the ADC noise.

If the whitening filters are ON, a pole and zero are expected to appear at 30 Hz and 3 Hz respectively according to the schematic, but no such features.

ETMY_WF2.png

 

  4827   Thu Jun 16 00:43:36 2011 KojiUpdateSUSVertex SUS Binary Output Boxes were turned off / need investigation

- I was investigating the SUS whitening issue.

- I could not find any suspension which can handle the input whitening switch correctly.

- I went to 1X5 rack and found that both of the two binary output boxes were turned off.
As far as I know they are pulling up the lines which are switched by the open collector outputs.

- I tried to turn on the switch. Immediately I noticed the power lamps did not work. So I need an isolated setup to investigate the situation.

- The cables are labelled. I will ask steve to remove the boxes from the rack.

  4828   Thu Jun 16 08:45:14 2011 steveUpdateSUSVertex SUS Binary Output Boxes removed

Quote:

- I was investigating the SUS whitening issue.

- I could not find any suspension which can handle the input whitening switch correctly.

- I went to 1X5 rack and found that both of the two binary output boxes were turned off.
As far as I know they are pulling up the lines which are switched by the open collector outputs.

- I tried to turn on the switch. Immediately I noticed the power lamps did not work. So I need an isolated setup to investigate the situation.

- The cables are labelled. I will ask steve to remove the boxes from the rack.

 I shut down damping to the Vertex optics and removed Binary IO  Adapter chassy BO0 and BO1

About a week ago I discussed the BO0's power indicator lights with Kiwamu. They were  not on or they were blinking on-off.

I put screws into ps connectors in the back, but it did not helped.

  4829   Thu Jun 16 23:19:09 2011 KojiUpdateSUSVertex SUS Binary Output Boxes removed

[Jamie, Koji]

- We found the reason why some of the LEDs had no light. It was because the LEDs were blown as they were directly connected to the power supply.
The LEDs are presumably designed to be connected to a 5V supply (with internal current-limiting resistor of ~500Ohm). The too much current
with the 15V (~30mA) made the LED blown, or the life-time of them shorter.

- Jamie removed all of the BO modules and I put 800Ohm additional resister such that the resultant current is to be 12mA.
The LEDs were tested and are fine now.

- The four BO boxes for C1SUS were restored on the rack. I personally got confused what should be connected where
even though I had labeled for BO0 and BO1. I just have connected CH1-16 for BO0. The power supplies have been connected only to BO0 and BO1.

- I tested the whitening of PRM UL sensor by exciting PRM UL sensor. The transfer function told us that the pendulum response can be seen
up to 10-15Hz. When the whitening is on, I could see the change of the transfer function in that freq band. This is good.
So the main reason why I could not see theis was that the power supply for the BOs were not turned on.

- I suppose Jamie/Joe will restore all of the BO boxes on the racks tomorrow. I am going to make a test script for checking the PD whitenings.

  4831   Fri Jun 17 08:03:48 2011 steveUpdateSUSITMY sus damping restored

ITMY sus damping restored.

 

  4833   Fri Jun 17 17:02:15 2011 JamieUpdateSUSETMX/ETMY binary output modules (re)installed, not yet tested

I have installed a new binary output module in ETMY, where there was none previously.  It is installed, powered (with working LEDs), hooked up (to the binary output card and the cross connect), but it hasn't been fully tested yet.

I also re-installed the binary output module in ETMX, with newly modified power-indicator LEDs.

Both modules are fully installed, but they have not yet been fully tested to confirm that they are indeed switching the whitening and de-whitening filters.

  4836   Mon Jun 20 09:04:13 2011 steveUpdateSUSETMX damping restored

ETMX sus damping restored

  4839   Mon Jun 20 11:04:03 2011 NicoleUpdateSUSWork Plan for Week 2

Here is my work plan for this week:

Current Week Plan (Week 2) (As of 6/17/11)

 

Setting Up for Horizontal Displacement Measurements

1) Help Steve clean small table for experiment

2) Remove aluminum base from TT suspension

3) Mount shaker onto table base

4) Mount horizontal slider onto table base

5) Connect TT suspension, shaker, and horizontal slider

Begin Assembly of Sensors

1) Begin building circuit for displacement photosensors

2) Calibrate photosensor using linear regions of power versus distance curves

3) Circuit box for photosensors?

  4844   Mon Jun 20 18:12:20 2011 NicoleUpdateSUSSmall Table Cleaned and Levelled

P6220198.JPG

The small optical bench (next to the MC-2 Chamber and the tool box tower) has been cleared of the misc. object previously on it, cleaned, and leveled (after much calibration X___X).

PLEASE, PLEASE, PLEASE do NOT MOVE OR HIT THE TABLE! It was incredibly painful to level.

This is how leveling the table made me feel...

P6220199.JPG

VERY SAD...so do not move please!

The shaker has already been moved to the table and the amplifier for my shaking experiment is located behind the table (not on the table, as to prevent scratching).

 

 

  4853   Wed Jun 22 12:24:44 2011 NicoleSummarySUSMidweek 2 Work Summary

I have made my transfer function model and posted it to the suspension wiki. Here is the link to my model!

Bode Plot Model

Please let me know if there need to be any adjustments, but I have posted the bode plots, a model image, and an explanation of why I think it's right! ^ ___^ V

I am currently working on the photo sensor circuit for the displacement detector. So far, I have gotten the infared LED to light up! ^ ___^ V

I am now trying to get a plot of forward voltage versus current for the LED. HOPEFULLY it will match the curve provided in the LED datasheet.

I'm using the bread board circuit box and when I'm not working at the bench, I have signs posted. PLEASE DO NOT REMOVE THE CONNECTIONS! It is

fine to move the bread board circuit box, but please do not disturb the connections > ____<

Here is a photo of the workspace

P6220200.JPG

  4858   Wed Jun 22 18:41:23 2011 NicoleSummarySUSBROKEN bread board circuit box and L9337 LED Current Versus Voltage Curve

NOTE: The potentiometers on the bread board circuit box (the one I have been using with the signal generator, DC power, LED displays, and pulse switches) is BROKEN!

The potential across terminals 1 and 2 (also 2&3) fluctuates wildly and there dial does not affect the potential for the second potentiometer (the one with terminals 4, 5, and 6).

This has been confirmed by Koji and Jaimie.  PS I didn't break it! >____<

 

NEVERTHELESS, using individual resistors and the 500 ohm trim resistor, I have managed to get the current versus forward voltage plot for the Hamamatsu L9337 Infared LED

LED_I_vs_V_exp_plot.png

  4868   Thu Jun 23 21:35:46 2011 Jamie, Rana, KiwamuUpdateSUSFix calibration for sus sensors

We have fixed the counts-to-micron (cts2um) calibration for the suspension sensor filters. Each suspension sensor filter bank (e.g. ULSEN) has a "cts2um" calibration filter. These have now been set with the following flat gains:

   40 V       10^3 um         um
 -------- *  --------  = .36  --
 2^16 cts     1.7 V           ct

The INMTRX was also fixed with proper element values:

UL UR LR LL SIDE  
.25 .25 .25 .25 0 POS
1.666 1.666 -1.666

-1.666

0 PIT
1.666 -1.666 -1.666 1.666 0 YAW
0 0 0 0 1 SIDE

This was done for all core optic suspensions (BS, PRM, SRM, ITMX, ITMY, ETMX, ETMY).

 

  4869   Thu Jun 23 22:00:22 2011 JamieUpdateSUSburt snapshot

I recorded a burt snapshot of these settings: /opt/rtcds/caltech/c1/burt/autoburt/snapshots/2011/Jun/23/21:40

  4875   Fri Jun 24 01:05:32 2011 NicoleSummarySUSTransfer Function Model Analysis Summary and New Posted LED V vs. I Curve

I have updated the TT suspension wiki to include a new page on my transfer function model. In this new page, an introduction and analysis of my transfer function (including a comparison of the transfer functions for a flexibly- and rigidly-supported damper) are included.  This page contains linear and logarithmic bode plots.  Here is a link to the transfer function page.

 

I have also updated my photosensor page on the TT suspension wiki so that the experimental data points in my current versus voltage plot are plotted against the curve provided by the Hamamtsu data sheet. I have also included an introduction and analysis for my mini-experiment with the forward voltage and forward current of the LED. Here is link to the photsosensor page.

  4876   Fri Jun 24 07:40:23 2011 steveUpdateSUSPRM damping restored

The PRM sus damping restored. C1:SUS-PRM_SDPD_VAR is still 20-30mV and going up.  Side gain  turned on. This pulled it down to 5-8 mV

Why is the side osem sensing voltage 4.4V ? It can not be higher than ~2.4V.......something is rotten in the state of Denmark?

Edit by KI:

 It's because Valera increased the transimpedance gain of the PRM SIDE OSEM to match the signal level to the new ADC range (#3913 ).

  4879   Fri Jun 24 17:04:25 2011 NicoleUpdateSUSBasic Laser Safety Training; Moved TT Mirror; Horizontal Displacement Mech Plan

Today Ishwita, Sonali, and I completed basic laser safety training with Peter King. I completed the Laser Safety Quiz and have turned in my certificate sheet.

I just need to turn in a signed copy of the Lab Safety Checklist to SFP (which I can now have signed by Koji after completing the course).

 

Steve and I have removed the TT mirror from the clean box. It is now on the small optical table in the lab that I have been working on.  Thanks to Steve, all of the mechanical components for the horizontal displacement measurement experiment are compiled and on the small optical table. Here is a photo of the small optical table with the gathered components. CompiledParts.JPG

The plan is to attach the slider and the shaker directly to the black mounting plate. On the slider, we we then place the smaller black mounting plate (with the lip). The lip will attach to the shaker. We know exactly where to drill and everything is lined up. The shaker will be placed on the smaller black mounting plate (with the lip).  The assembly will begin on Monday.

 

Here is a photo of the planned set-up for the shaker and the horizontal slider + mounting base.

 HorizontalDispMount.JPG

  4887   Sun Jun 26 18:35:16 2011 ranaHowToSUSfree swing all optics

I used scripts/SUS/freeswing-all.csh to give the optics a kick and then turn off their watchdogs and collect the free swinging data.  Final script end time = 993173551. Start taking data ~ 993173751

I had to fix up the script a little: it had amateur stuff in there, such as undefined variables.

It still doesn't work that well. On the new Ubuntu workstations, pianosa, it fails by just not setting some of the EPICS variables using the EZCA stuff.

On Allegra, it failed on ~1 out of 10 commands by returning "epicsThreadOnce0sd epicsMutexLock failed" ???

On Pianosa, it sometimes says, instead, "epicsThreadOnceOsd: pthread_mutex_lock returned Invalid argument.".   Ah...now I understand?

So finally, I had to run the script on op340m to get it to actually run all of its commands. That's right; I used a 15 year old Solaris 9 Blade 150 because none of our fancy new Linux machines could do the job reliably.

Fixing our EZCA situation is a pretty high priority; if the locking scripts fail to run ~1 command every hour its going to completely derail the lock acquisition attempts.

If you want to use the IFO tonight, just run the script again on op340m again when you're done.

  4892   Tue Jun 28 01:18:53 2011 ranaHowToSUSfree swing all optics

Chris Wipf tells me that the EPICS Mutex Jumbo Mumbo can be overcome by upgrading our EPICS. We should get one of Jamie's assistants to get this going on one of the Ubuntu workstations.

  4902   Tue Jun 28 21:05:05 2011 JamieUpdateSUSSUS control model updated

I have updated the sus_single_control model, adjusting/cleaning up/simplifying the LSC/POS input signals, and routing new signals to the lockins. Notably one of POS inputs to the part ("lockin_in") was eliminated (see below).

The 6 inputs to the TO_COIL output matrix are now:

LSCPOS + OFFSET + ALT_POS_IN
ASCPIT + OFFSET + SUSPIT + OLPIT
ASCYAW +OFFSET + SUSYAW + OLYAW
SIDE
LOCKIN1
LOCKIN2

The ALT_POS input is used only by the ETMs for the green locking. Just outside of the sus_single_control library part in the ETM models are the green locking controls, consisting of the ETM?_ALS filter bank and the ETM?_GLOCKIN lockin, the outputs from which are summed and fed into the aforementioned ALT_POS input.

As for the SUS lockins (LOCKIN1 and LOCKIN2 in the library model), their input matrix now gets the direct inputs from the OSEMS (before filtering) and the outputs to the coils, after all filtering. These will aid in doing binary output switching tests.

All suspension models (c1sus, c1scx, c1scy) have been rebuild and restarted so that they reflect these changes.

  4904   Tue Jun 28 22:36:04 2011 JamieUpdateSUSChecking binary switching of SUS whitening filter

I have been checking the binary output switching for the SUS whitening filters. It appears that the whitening switching is working for (almost) all the vertex suspensions (BS, ITMX, ITMY, PRM, SRM), but not for the ETMs.

The table below lists the output from my switch-checking script (attached). The script uses the SUS digital lockin to drive one coil and measure the same coil's OSEM response, repeating for each coil/OSEM pair. I used a lockin drive frequency of about 10 Hz, at which the whitening filter should have 10 db of gain.

All but one of the vertex OSEMS show the proper response (~10db gain at 10Hz) when the whitening is switched on from the digital controls. ITMY UL appears to not be switching, which I fear is due to my electronics fail noted in my previous log post.  The ETMs are clearly not switching at all.

I will try to get the ETM switching working tomorrow, as well as try to asses what can be done about the ITMY UL switch.  After that I will work on confirming the coil drive dewhite switching.

lockin settings

freq: 10.123 Hz
amp: 10000
I/Q filters: 0.1 Hz LP, 4-pole butterworth

response

BS
ul : 3.31084503062 = 10.3987770676 db
ll : 3.34162124753 = 10.4791444741 db
sd : 3.43226254574 = 10.7116100229 db
lr : 3.28602651913 = 10.3334212798 db
ur : 3.29361593249 = 10.3534590969 db

ITMX
ul : 3.37499773336 = 10.5654697099 db
ll : 3.2760924572  = 10.3071229966 db
sd : 3.13374799272 =  9.9212813757 db
lr : 3.28133776018 = 10.3210187243 db
ur : 3.37250879937 = 10.5590618297 db

ITMY
ul : 0.99486434364 = -0.0447226830807 db
ll : 3.39420873724 = 10.6147709414 db
sd : 3.88698713176 = 11.7922620572 db
lr : 3.357123865   = 10.5193473069 db
ur : 3.37876008179 = 10.5751470918 db

PRM
ul : 3.26758918055 = 10.2845489876 db
ll : 3.32023820566 = 10.4233848529 db
sd : 3.25205538857 = 10.2431586766 db
lr : 3.24610681962 = 10.227256141  db
ur : 3.31311970305 = 10.4047425446 db

SRM
ul : 3.30506423619 = 10.3835980943 db
ll : 3.28152094133 = 10.3215036019 db
sd : 3.08566647696 =  9.7869796462 db
lr : 3.30298270419 = 10.378125991  db
ur : 3.3012249406  = 10.3735023505 db

ETMX
ul : 0.99903400106 = -0.00839461539757 db
ll : 0.99849991349 = -0.0130393683795 db
sd : 1.00314092883 =  0.0272390056874 db
lr : 1.00046493718 =  0.00403745453682 db
ur : 1.00265600785 =  0.0230392084558 db

ETMY
ul : 1.00223179107 =  0.0193634913327 db
ll : 0.96755532811 = -0.286483823189 db
sd : 1.00861855271 =  0.0745390477589 db
lr : 1.05718545676 =  0.483023602007 db
ur : 0.99777406174 = -0.0193558045143 db
  4906   Wed Jun 29 01:23:21 2011 haixingUpdateSUSissues in the current quad maglev system

Here I show several issues that we have encountered in the quad magnetic levitation system. It would be great if you can give
some suggestions and comments (Poor haixing is crying for help)

The current setup is shown by the figure below (I took the photo this morning):

config_2.png

Basically, we have one heavy load which is rigidly connected to a plane that we try to levitate. On corners of the
plane, there are four push-fit permanent magnets. Those magnets are attracted by four other magnets which are
mounted on the four control coils (the DC force is to counteract the DC gravity). By sensing the position of the plane
with four OSEMs (there are four flags attached on the plane), we try to apply feedback control and levitate the plane.
We have made an analog circuit to realize the feedback, but it is not successful. There are the following main issues
that need to be solved:

(1) DC magnetic force is imbalanced, and we found that one pair has a stronger DC force than others. This should
be able to solved simply by replacing them with magnets have comparable strength to others.

(2) The OSEM not only senses the vertical motion, but also the translational motion. One possible fast solution is to
cover the photodiode and only leave a very thin vertical slit so that a small translational motion is not sensed.
Maybe this is too crappy. If you have better ideas, please let me know. Koji suggested to use reflective sensing
instead of OSEM, which can also solve the issue that flags sometimes touche the hole edge of the OSEM and
screw up the sensing.

(3) Cross coupling among different degrees of freedom. Basically, even if the OSEM only senses the vertical motion,
the motion of four flags, which are rigidly connected to the plane, are not independent. In the ideal case, we only
need to control pith, yaw and vertical motion, which only has three degrees of freedom, while we have four sensing outputs
from four OSEMs. This means that we need to work out the right control matrix. Right now, we are in some kind of dilemma.
In order to obtain the control matrix, we first have to get the sensing matrix or calibrate the cross coupling; however, this is
impossible if the system is unstable. This is very different from the case of quad suspension control used in LIGO,
in which the test mass is stable suspended and it is relatively easy to measure the cross coupling by driving the test mass
with coils. Rana suggested to include a mechanical spring between the fixed plane and levitated plane, so that
we can have a stable system to start with. I tried this method today, but I did not figure out a nice way to place the spring,
as we got a hole right in the middle of the fixed plane to let the coil connectors go though. As a first trial, I plan to
replace the stop rubber band (to prevent the plane from getting stuck onto the magnets) shown in the figure with mechanical
springs. In this case, the levitated plane is held by four springs instead of one. This is not as good as one, because
of imbalance among the four, but we can use this setup, at least, to calibrate the cross coupling. Let me know if you come
up better solution.

After those issues are solved, we can then implement Jamie's Cymac digital control, which is now under construction,
to achieve levitation.

  4907   Wed Jun 29 11:13:13 2011 JenneUpdateSUSissues in the current quad maglev system

magnetQuote


(1) DC magnetic force is imbalanced, and we found that one pair has a stronger DC force than others. This should
be able to solved simply by replacing them with magnets have comparable strength to others.

 I don't know if this would work, but it might be worth a try:

You've achieved single levitation before, with fairly good stability.  Can you try taking each magnet + coil and finding the DC coil current required to hold a mass at a given position?  If you can hold the same mass at the same place with all the different magnets+coils, then you're exerting the same force against gravity, so your DC forces are balanced. 

  4908   Wed Jun 29 11:25:07 2011 NicoleSummarySUSWeekly Summary of Work

Update of Week 3 Work:

-I've finished reading The Art of Electronics Ch 1, 2, and 4.

-The mechanical stage for the horizontal displacement measurements is set up.

-I've opened up the circuit box for the quad photodiode and am currently working on the circuit diagram for the box and for the quad photodiode sensors.

 

Later this week, I plan to finish the circuit diagrams and figure out how the circuits work with the four inputs. I also plan to start working on my first

progress report.

 

  4913   Wed Jun 29 22:35:06 2011 NicoleSummarySUSCompleted Quad photodiode Box Circuit Diagrams

I have finished drawing the circuit diagrams for the quad photodiode boxes. Here are copies of the circuit diagram.

There are three main operation circuits in the quad photdiode box: a summing circuit (summing the contributions from the four inputs),

a Y output circuit (taking the difference between the input sums 3+2 and 1+4), and an X output circuit (taking the difference between the

input sums 3+4 and 1+2). I will complete an mini report on my examination and conclusions of the QPD circuit for the suspension wiki tomorrow.

summingcircuit.jpgQPDYcircuit.jpgQPDX_2circuit.jpg

 

  4916   Thu Jun 30 01:50:02 2011 JenneUpdateSUSITMX whitening, ETMX left free swinging

While closing up the whitening shop for the night, I noticed that the ITMX whitening state (Whitening "On") is opposite that of all other suspensions (they all have Whitening "Off").  I don't know which way is correct, but I assume they should all be the same.  Once all the whitening and BO testing is done, we should make sure that they're all the way we want them to be.

Also, Koji and I are leaving ETMX free swinging.  That's the way we found it, presumably from Jamie's BO testing at the end station today.  We don't know what the optic's story is, so we're leaving it the way we found it.  Jamie (or whomever left it free swinging), can you please restore it when it is okay to do so?  Thanks!

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