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ID Date Author Typedown Category Subject
  3596   Thu Sep 23 02:23:04 2010 koji,taraSummaryElectronicsTesting new TTFSS

I tested the new table top frequency stabilization system(TTFSS),
I haven’t finished it yet, and accidentally fried one amplifier in the circuit.

We received three sets of a new TTFSS system which will replace the current FSS.
It needs to be checked that the system works as specified before we can use it.

- Result

I followed the instruction written on E10000405-v1
The first test inspected how much the currents were drawn from the +/- 24 V power supply.
+24 V drew 350 mA and -24 V drew 160 mA as shown on pwr supply’s current monitor.
They exceeded the specified value which was 200 +/- 20 mA, but nothing went wrong during the test.
Nothing got overheated, all voltage outputs were correct so I proceeded.
I have gone down the list to 6, and everything works as specified.

- Correcting the document for the test procedure

I found a few errors on the instruction document. I’ll notify the author tomorrow.

- How GVA-81 amplifier on D0901894 rev A got fried

During the test, I used a mirror on a stick that looked like a dental tool to see under the board.
Unfortunately, the steel edge touched a board and caused a spark. The voltage on -24 dropped to -16.
I think this happened because the pwr supply tried to decrease the current from shorted circuit,
as I shorted it only short time ( a blink of an eye), it could not reduce the voltage to zero.
When I was checking the power supply and about to adjust the voltage back to the right value
(about 4-5 seconds after the spark,) smoke came out of the circuit.

Koji investigated the circuit and found that a GVA 81 amplifier was broken.

This was checked by applying 5V to the amp, and slightly increasing the current.
The voltage dropped to zero as the amp was broken, so its circuit was shorted.

I’ll see if I can replace this at EE lab at Downs.
If I cannot find a spare one, I’ll replace it with a resistor and resume the test procedure.
Because it amplifies LO signal, which won’t be used during the test.

  3597   Thu Sep 23 02:45:30 2010 KojiSummaryComputersnodus gracefully rebooted

Zach> Nodus seemed to be working fine again, and I was browsing the elog with no
Zach> problem. I tried making an entry, but when I started uploading a file it
Zach> became unresponsive. Tried SSHing, but I get no prompt after the welcome
Zach> blurb. ^C gives me some kind of tcsh prompt (">"), which only really
Zach> responds to ^D (logout). Don't know what else to do, but I assume someone
Zach> knows what's going on.

By gracefully rebooting nodus, the problem was solved.


It (">") actually was the tcsh prompt, but any commands with the shared or dynamic link libraries looked unfunctional.

I could use
    cd /.../...
and
    echo *
to browse the directory tree. The main mounted file systems like /, /usr, /var, /cvs/cds/caltech looked fine.
I was afraid that the important library files were damaged.

I tried
    umountall
and
    mountall
in order to flush the file systems.
These should run even without the libraries as mount must properly work even before /usr is mounted.

They indeed did something to the system. Once I re-launch a new login shell, the prompt was still ">"
but now I could use most of the commands.

I have rebooted by usual sudo-ing and now the services on nodus are back to the functional state again.

# nodus was working in the evening at around 9pm. I even made an e-log entry about that.
# So I like to assume this is not directly related to the linux1 incident. Something else could have happened.

  3603   Thu Sep 23 23:24:43 2010 rana, johnny, taraSummaryPSLAM modulate AOM to measure RefCav Thermo-Optic coefficient

Big Johnny and I hacked a function generator output into the cross-connect of the 80 MHz VCO driver so that we could modulate the

amplitude of the light going into the RefCav. The goal of this is to measure the coefficient between cavity power fluctuations and the

apparent length fluctuations. This is to see if the thermo-optic noise in coatings behaves like we expect.

 

To do this we disconnected the wire #2 (white wire) at the cross-connect for the 9-pin D-sub which powers the VCO driver. This is

called VCOMODLEVEL (on the schematic and the screen). In the box, this modulates the gain in the homemade high power Amp which

sends the actual VCO signal to the AOM.

 

This signal is filtered inside the box by 2 poles at 34 Hz. I injected a sine wave of 3 Vpp into this input. The mean value was 4.6 V. The

RCTRANSPD = 0.83 Vdc. We measure a a peak there of 1.5 mVrms. To measure the frequency peak we look in

the FSS_FAST signal from the VME interface card. With a 10 mHz linewidth, there's no peak in the data above the background. This signal

is basically a direct measure of the signal going to the NPRO PZT, so the calibration is 1.1 MHz/V.

 

We expect a coefficient of ~20 Hz/uW (input power fluctuations). We have ~1 mW into the RC, so we might expect a ~20 Hz frequency shift.

That would be a peak-height of 20 uV. In fact, we get an upper limit of 10 uV.


 Later, with more averaging, we get an upper limit of 1e-3 V/V which translates to 1e-3 * 1.1 MHz / 1 mW ~ 1 Hz/uW. This is substantially lower

than the numbers in most of the frequency stabilization papers. Perhaps, this cavity has a very low absorption?

  3620   Wed Sep 29 12:08:28 2010 josephb, alexSummaryCDSLast burt save of old controls

This is being recorded for posterity so we know where to look for the old controls settings.

The last good burt restore that was saved before turning off scipe25 aka c1dcuepics was on September 29, 11:07.

  3647   Tue Oct 5 11:42:20 2010 kiwamuSummaryGreen Lockingdeveloping green locking plant

 With a help from Joe, I made a diagram of the simulated plant for green locking in order to get better understanding and consensus.

Eventually these simulated plants will help us developing (sometimes debugging) the digital control systems.

Here is the diagram which tells us how we will setup and link the control/plant models and on which machine they will be running.

green_sm3.png

 

Basically upper side represents the realtime control, and the lower side is the simulated plant.

The models are talking to each other via either a local shared memory (orange line) or the reflective memory network (purple line).

 Each model is stil not systematically named, at some point we have to have an absolute standard for naming the models.

 

- current model names -

  GCV = Green Control model at Vertex

  GCX(Y) = Green Control model at X (Y) end

  GPV = Green Plant model at Vertex

 

 - things to be done -

1. let the RFM work

2. revise the old plant models : SUP, SPX(Y) and LSP

 

  3655   Tue Oct 5 18:27:18 2010 Joonho LeeSummaryElectronicsCCD cable's impedence

Today I checked the CCD cables which is connected to the VIDEOMUX.

17 cables are type of RG59, 8 cables are type of RG58. I have not figured out the type of other cables(23 cables) yet.

The reason I am checking the cables is for replacing the cables with impedance of 50 or 52 ohm by those with impedance of 75 ohm.

After I figures out which cable has not proper impedance, I will make new cables and substitute them in order to match the impedance, which would lead to better VIDEO signal.

To check the impedance of each CCD cable, I went to the VIDEOMUX and looked for the label on the cable's surface.

Type of RG59 is designated to the cable of impedance 75ohm. I wrote down each cable's input or output channel number with observation(whether it is of type RG59 or not).

The result of observation is as follows.

Type channel number where it is connected to
Type 59 in#2, in#11, in#12, in#15, in#18, in#19, in#22, in#26, out#3, out#4, out#11, out#12, out#14, out#17, out#18, out#20, out#21
Type 58 in#17, in#23, in#24, in#25, out#2, out#5, out#7, out#19
unknown type others

 

For 23 cables that I have not figured out their type, cables are too entangled so it is limited to look for the label along each cable.

I will try to figure out more tomorrow. Any suggestion would be really appreciated.

  3657   Wed Oct 6 00:32:01 2010 ranaSummaryDAQNDS2

This is the link to the NDS2 webpage:

https://www.lsc-group.phys.uwm.edu/daswg/wiki/NetworkDataServer2

We should install this so that we can use this modern interface to get 40m data from outside and inside of the 40m.

  3660   Wed Oct 6 14:49:54 2010 ranaSummaryloreSteve on the sea

jacques.jpg

  3685   Sun Oct 10 18:09:02 2010 KojiSummaryCOCPhase map interferometer calibration for the data on Oct 8th, 2010

Summary:

Calibration of the phase map interferometer was calculated for the data on Oct 8th, 2010.
The calibration value is 0.1905 mm/pixel.

This is slightly smaller than the assumed value in the machine that is 0.192mm/pixel.
This means that the measured radii of curvature must be scaled down with this ratio.
(i.e. RoC(new) = RoC(old) / 0.1922 * 0.19052)


Motivation:

Our tagets of the phasemap measurement are:

1. Measure the figure errors of the mirrors
2. Measure the curvature of the mirrors

The depth of the mirror figure is calibrated by the wavelength of the laser (1064nm).
However, the lateral scale of the image is not calibrated.
Although Zygo provides the initial calibration as 0.192 mm/pixel, we should measure the calibration by ourselves.

Method:

We found an aperture mask with a grid of holes with 2mm diameter and 3mm spacing (center-to-center).
Take the picture of this aperture and calibrate the pixel size. The aperture is made of stainless and makes not interference
with the reference beam. Thus we put a dummy mirror behind the aperture. (UPPER LEFT plot)

As the holes are aligned as a grid, the FFT of the aperture image shows peaks at the corresponding pitches. (UPPER MIDDLE plot)
As the aperture was slightly rotated, the grids of the peaks are also slanted.

We can obtain the spacing of the peak grids. How can we can that values precisely? I decided to make an artificial mask image.
The artificial mask (LOWER LEFT plot) has the similar FFT pattern (LOWER MIDDLE plot). The inner product of the two
FFT results (i.e. Sum[abs(fft1) x abs(fft2)]), quite a large value is obtained if the grid pitch and the aperture angle agrees between those images.
Note that the phase information was discarded. The estimated grid spacing of the artificial mask can be mathematically obtained.

Result:

The grid pitch and the angle were manually set as initial values. Then the parameters to give the local maximum was obtained by fminsearch of Matlab.
UPPER RIGHT and LOWER RIGHT plots show the scan of the evaluation function by changing the angle and the pitch. They behave quite normal.

The obtained values are

Grid pitch: 15.74 pixel
Angle: 1.935 deg

As the grid pitch is 3mm, the calibration is

3 mm / 15.74 pixel = 0.1905 mm/pixel

Discussion:

A spherical surface can be expressed as the following formula:

z = R - R Sqrt(1-r2/R2)      (note: this can be expanded as r2/(2 R)+O(r3) )

Here R is the RoC and r is the distance from the center. This means that the calibration of r quadratically changes the curvature.
We have measured the RoC of the spare SRM. We can compare the RoCs measured by this new metrology IFO and the old one,
as well as the one by Coastline optics. 

 

Attachment 1: calibration.pdf
calibration.pdf
  3686   Sun Oct 10 18:28:25 2010 kiwamuSummarySUSITMX OSEM offsets

Because of the in-vac work on Oct. 4th (see this entry) , ITMX's OSEM offsets were changed.

The two upper OSEMs are still fine, but LL and LR seem to be out of the OSEM's range. 

The plot below shows the trends of LL's and LR's readouts for about two weeks. (The channel name are in the old convention, i.e. ITMY)

OSEM.png

 Some data were missing due to the upgrade of the frame builder.

 It is apparent that the offsets are changed after the in-vac work on Oct. 4th, and now they just show almost zero numbers.

 

The damping of ITMX can still work, if LL and LR are disabled.

At some point before pumping down, we have to check the leveling of the ITMX table again.

  3689   Mon Oct 11 16:09:10 2010 yutaSummarySUScurrent OSEM outputs

Background:
 The output range of the OSEM is 0-2V.
 So, the OSEM output should fluctuate around 1V.
 If not, we have to modify the position of it.

What I did:
 Measured current outputs of the 5 OSEMs for each 8 suspensions by reading sensor outputs(C1:SUS-XXX_YYPDMON) on medm screens.

Result:

  BS ITMX ITMY PRM SRM MC1 MC2 MC3
UL 1.20 0.62 1.69 1.18 1.74 1.25 0.88 1.07
UR 1.21 0.54 1.50 0.99 1.77 1.64 1.46 0.31
LR 1.39 0.62 0.05 0.64 2.06 1.40 0.31 0.19
LL 1.19 0.88 0.01 0.64 1.64 1.00 0.05 1.03
SD 1.19 0.99 0.97 0.79 1.75 0.71 0.77 0.93

 White: OK (0.8~1.2)
 Yellow: needs to be fixed
 Red: BAD. definitely need fix

  3694   Mon Oct 11 23:55:25 2010 Joonho LeeSummaryElectronicsCCD cables for output signal

Today I checked all the CCD cables which is connected output channels of the VIDEOMUX.

Among total 22 cables for output, 18 cables are type of RG59, 4 cables are type of RG58.

The reason I am checking the cables is for replacing the cables with impedance of 50 or 52 ohm by those with impedance of 75 ohm.

After I figures out which cable has not proper impedance, I will make new cables and substitute them in order to match the impedance, which would lead to better VIDEO signal.

 

Today, I labeled all cables connected to output channels of VIDEO MUX and disconnect all of them since last time it was hard to check every cable because of cables too entangled.

With thankful help by Yuta, I also checked which output channel is sending signal to which monitor while I was disconnecting cables.

Then I checked the types of all cables and existing label which might designate where each cable is connected to.

After I finished the check, I reconnected all cables into the output channel which each of cable was connected to before I disconnected.

 

4 cables out of 22 are type of RG58 so expected to be replace with cable of type RG59.

The result of observation is as follows. 

Ch#
where its signal is sent type
1 unknown 59
2 Monitor#2  58
3 Monitor#3 59
4 Monitor#4 59
5 Monitor#5 58
6 Monitor#6 59
7 Monitor#7 58
8 unknown / labeled as "PSL output monitor" 59
9 Monitor#9 59
10 Monitor#10 59
11 Monitor#11 59
12 Monitor#12 59
13 Unknown 59
14 Monitor#14 59
15 Monitor#15 59
16 unknown / labeled as "10" 59
17 unknown 59
18 unknown / labeled as "3B" 59
19 unknown / labeled as "MON6 IR19" 58
20 unknown 59
21 unknown 59
22 unknown 59

I could not figure out where 10 cables are sending their signals to. They are not connected to monitor turned on in control room

so I guess they are connected to monitors located inside the lab. I will check these unknown cables when I check the unknown input cables.

Next time, I will check out cables which is connected to input channels of VIDEIO MUX. Any suggestion would be really appreciated.

  3738   Mon Oct 18 18:33:46 2010 KojiSummaryCOCSummary of the main mirrors & their phasemap measurement

I have made a summary web page for the 40m upgrade optics.

https://nodus.ligo.caltech.edu:30889/40m_phasemap/

I made a bunch of RoC calculations along with the phase maps we measured.
Those are also accommodated under this directory structure.

Probably.... I should have used the wiki and copy/paste the resultant HTML?

  3739   Mon Oct 18 22:11:32 2010 Joonho LeeSummaryElectronicsCCD cables for input signal

Today I checked all the CCD cables which is connected input channels of the VIDEOMUX.

Among total 25 cables for output, 12 cables are type of RG59, 4 cables are type of RG58, and 9 cables are of unknown type.

The reason I am checking the cables is for replacing the cables with impedance of 50 or 52 ohm by those with impedance of 75 ohm.

After I figures out which cable has not proper impedance, I will make new cables and substitute them in order to match the impedance, which would lead to better VIDEO signal.

 

Today, I check the cables in similar way as I did the last time.

I labeled all cables connected to input channels of VIDEO MUX and disconnect all of them since last time it was hard to check every cable because of cables too entangled.

Then I checked the types of all cables and existing label which might designate where each cable is connected to.

After I finished the check, I reconnected all cables into the input channel which each of cable was connected to before I disconnected.

 

4 cables out of 25 are type of RG58 so expected to be replace with cable of type RG59.

9 cables out of 25 are of unknown type. These nine cables are all orange-colored thick cables which do not have any label about the cable characteristic on the surface.

The result of observation is as follows.

Note that type 'TBD-1' is used for the orange colored cables because all of them look like the same type of cable.

 

Channel number where its signal is coming type
1 C1:IO-VIDEO 1 MC2 TBD-1
2 FI CAMERA 59
3 PSL OUTPUT CAMERA 59
4 BS  C:1O-VIDEO 4 TBD-1
5 MC1&3 C:1O-VIDEO 5 59
6 ITMX C:1O-VIDEO 6 TBD-1
7 C1:IO-VIDEO 7 ITMY TBD-1
8 C1:IO-VIDEO 8 ETMX TBD-1
9 C1:IO-VIDEO 9 ETMY TBD-1
10 No cable is connected
(spare channel)
 
11 C1:IO-VIDEO 11 RCR 59
12 C1:IO-VIDEO RCT 59
13 MCR VIDEO 59
14 C1:IO-VIDEO 14 PMCT 59
15 VIDEO 15 PSL IOO(OR IOC) 59
16 C1:IO-VIDEO 16 IMCT TBD-1
17 PSL CAMERA 58
18 C1:IO-VIDEO 18 IMCR 59
19 C1:IO-VIDEO 19 SPS 59
20 C1:IO-VIDEO 20 BSPO TBD-1
21 C1:IO-VIDEO 21 ITMXPO TBD-1
22 C1:IO-VIDEO 22 APS1 59
23 ETMX-T 58
24 ETMY-T 58
25 POY CCD VIDEO CH25 58
26 OMC-V 59

Today I could not figure out what impedance the TBD-1 type(unknown type) has.

Next time, I will check out the orange-colored cables' impedance directly and find where the unknown output signal is sent. Any suggestion would be really appreciated.

  3749   Thu Oct 21 01:11:48 2010 ranaSummaryComputerselog change and rossa tex

I deleted a bunch of categories from the elogd.cfg file. Not every kind of locking and activity gets its own activity. All of the things related to length sensing and control should be LSC. If there's a high pollen count its under PEM. etc., etc., etc.

I decided that the 'tetex' distribution which comes with CentOS is total BS and I removed it from rossa using 'yum erase tetex'. I installed TexLive using the instructions on the web; its much better, actually works, and also has RevTex 4.1 which allows Jenne and I to write our paper.

Eventually, we'll standardize our workstation setups.

Yuta has also successfully set up zita to run the projector, so we should clear our some of the boxes and bookshelves in that area so that the projection can be larger.

  3753   Thu Oct 21 13:05:19 2010 KojiSummaryComputerselog change and rossa tex

This is cool though the projector is flashing the blue screen alternately.

I gave the dual head video card (ATI RADEON something) to Yuta a month ago.
It is on the top of Zita. This would make the things more fun.

Quote:

Yuta has also successfully set up zita to run the projector, so we should clear our some of the boxes and bookshelves in that area so that the projection can be larger.

 

  3765   Fri Oct 22 19:53:27 2010 yutaSummaryCDSconversion failure in digital filters

(Rana, Joe, Yuta)

We now understand that we never succeeded in converting old fiter files to new filter files.

For example, we just changed the sampling rate with coefficients remained and foton confused, or we forgot to rename some of the module names(ULSEN -> SUS_MC1_ULSEN) ......

This is why we sometimes damped and sometimes didn't, depending on filter switches. New filter files has been always wrong.

So, we started to convert them again.
We have to figure out how to convert the files that Foton accepts correctly.

  3770   Sat Oct 23 14:42:01 2010 yutaSummaryCDSdamped MC suspensions

After replacing filters, MC suspensions damped  last night.

Further measurement next time.

Attachment 1: dam.png
dam.png
  3771   Sun Oct 24 18:06:35 2010 kiwamuSummaryLockingsetup for green beat

green_beat_note.png

(notes on signal level)

 The signal level of the observed peak was -48dBm.

However I was expecting it is like -28dBm with some ideal assumptions.

There may be a 20dB unknown loss which sounds big to me.

 

The expectation was calculated by using the following simple math.

                       SIGNAL = A x Z x G_RF x sqrt(P1 / 2) x sqrt (P2 / 2)

 where A is the responsibility of the PD and Z is the trans impedance gain. G_RF is a gain of the RF amplifier.

The laser powers of green beams, P1 and P2, are divided by 2 due to a beam splitter. 

I was assuming the parameters are like:

           A = 0.39 [A/W]   (assuming 90% quantum efficiency at 532nm)

           Z = 240 [V/A]  

           P1 = 17 uW  (measured by Newport power meter)

           P2 = 30 uW (measured by Newport power meter)

           G_RF = 23 dB

 

  3774   Mon Oct 25 02:14:38 2010 KojiSummaryLockingsetup for green beat

- What is the actual photocurrent for the beam1 and beam2? We don't care how much power do you have before the BS, but care how much current do you have on the PD.

- How much is the visibility? There is mismatching of the beams. i.e. The beam diameter looked quite different. Also the beams are not TEM00 but have fringes probably comes from the TT mirrors. You maybe able to measure the visibility by the DC output, making the beat freq go through df=0 slowly.

- What is the measured gain of the RF amp? Does it include the voltage division by the output/input impedance?

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

 The signal level of the observed peak was -48dBm.

However I was expecting it is like -28dBm with some ideal assumptions.

There may be a 20dB unknown loss which sounds big to me.

I was assuming the parameters are like:

           A = 0.39 [A/W]   (assuming 90% quantum efficiency at 532nm)

           Z = 240 [V/A]  

           P1 = 17 uW  (measured by Newport power meter)

           P2 = 30 uW (measured by Newport power meter)

           G_RF = 23 dB

  3815   Thu Oct 28 23:17:15 2010 yutaSummaryCDS[EMERGENCY] accidentally deleted daqd

Rana showed me that if c1sus machine runs c1mcs stuff(and c1x02 stuff) only, we can use dataviewer without crashing fb.
Also, if we set correct NDS server and port(fb/8088), we can use diaggui on every machine.


During my investigation on what he did, I accidentally deleted daqd......
I am very very sorry.

I don't know if it helps or not, but all I have is the following information:

[Backup?]
    /opt/rtcds/caltech/c1/target/fb/daqd.25sep10


[What I deleted]
   -rwxr-xr-x 1 controls controls 6583071 Oct  1 11:57 daqd


[help message for daqd existed]
CDS Data Acquisition Server, Frame Builder, version 2.0
California Institute of Technology, LIGO Project
Client communication protocol version 11.4

Usage:
        daqd [-f <input frame file name>]
        [-c <configuration file (default -- $HOME/.daqdrc)>]

        [-s <frame writer pause usec (default -- 1 sec)>]


This executable compiled on:
        Fri Oct  1 10:33:18 PDT 2010
        Linux fb 2.6.34.1 #7 SMP Fri Sep 24 14:09:53 PDT 2010 x86_64 Dual-Core AMD Opteron(tm) Processor 8220 AuthenticAMD GNU/Linux



Please help me, Joe.

  3816   Fri Oct 29 01:18:03 2010 KojiSummarySUSPRM standoff glued

[Suresh Koji]

The standoff glued. The incandescent lamp set for curing the epoxy.


Jenne and Suresh did the balancing job. The next job was to glue it.

They ran out of the clear epoxy, and tried to use the grey epoxy which we used on the other suspensions for the upgrade.
They found that the solution A with grey color one was dried out and grainy.

We made a test piece of the grey epoxy (mixed with the solution B) in order to see the glue is still usable or not.
After the PMA party, we found that the glue was not stiffening but brittle. We judged that the grey epoxy is no longer useful.

Steve found a pack of Vac Seal in the chemical fridge. We decided to use this one for the gluing of the standoff.

After the gluing, we set an incandescent lamp to make the glue warm. 

Finally, we wrapped the suspension tower with Al foils and turned the HEPA fans again.

Attachment 1: IMG_3674.jpg
IMG_3674.jpg
  3821   Fri Oct 29 11:25:15 2010 josephb, yutaSummaryCDS[EMERGENCY] accidentally deleted daqd

Problem:

Missing daqd file, i.e. the framebuilder executable.

Solution:

1) Go to /opt/rtcds/caltech/c1/core/advLigoRTS/

2) Look in the Makefile for a likely build suspect.  In this case it was build dc, which stands for data concentrator.

3) So we ran "make dc"

4) Go to the sub-directory build/dc/ and then copy the daqd file there to the /opt/rtcds/caltech/c1/target/fb directory

5) Test it to ensure we're getting channels (Yay!)

Future Safeguards:

Place the new target directory under SVN control.

 

  3828   Fri Oct 29 18:37:33 2010 yutaSummaryCDSdaqd and current CDS status

Background:
  Before Joe left(~ 1 hour ago), fb was working for a while. But after he left, daqd core dumped.
  This is maybe because we started c1sus and c1rms again for a delay measurement, just before he left.

What I did:
  I restarted IOP(c1x02) and FE models.
  Now it seems OK (we can use dataviewer and diaggui), but daqd reports bunch of errors like;

CA.Client.Exception...............................................
    Warning: "Identical process variable names on multiple servers"
    Context: "Channel: "C1:SUS-ITMX_TO_COIL_0_3_INMON", Connecting to: 192.168.113.85:42367, Ignored: c1susdaq:42367"
    Source File: ../cac.cpp line 1208
    Current Time: Fri Oct 29 2010 18:07:39.132686519
..................................................................


tp node xx invalid  (xx is 38 to 36)

Current CDS status:

MC damp dataviewer diaggui AWG c1ioo c1sus c1iscex RFM Sim.Plant  ...
                   ... 

   Please add other stuff you need.

Below is an example of how the color code works:

06-25-2009.NN_24ThreatLevel.GJH2L69BK.1.jpg

  3829   Sat Oct 30 05:27:53 2010 yutaSummaryCDSCDS time delay measurement

Motivation:
  We want to know the time delay of CDS in the IOP scheme.

Setup:
delaysetup.png

What I did:
1. Plugged out SCSI cable from ADC card 2 and DAC card 0 on C1SUS machine.
   ADC card 2 is ADC 0
   DAC card 0 is DAC 0

2. Measured tranfer function between ADC and DAC by SR785 and compared with the downsampling filter in IOP with 65534Hz(=4x16384Hz) sampling frequency.

  As ADC_0_0 corresponds to PRM ULSEN input and DAC_0_0 corrsponds to ULCOIL output, we turned all the filters off and set gains to 0 or 1 so that TF between ULSEN to ULCOIL will be ideally 1. (see this wiki page for channel assigns)

  The filter coefficients for the down sampling filter was found in;
    /cvs/cds/rtcds/caltech/c1/core/advLigoRTS/src/fe/controller.c
  It was named feCoeff4x.

static double feCoeff4x[9] =
        {0.014805052402446,
        -1.71662585474518,    0.78495484219691,   -1.41346289716898,   0.99893884152400,
        -1.68385964238855,    0.93734519457266,    0.00000127375260,   0.99819981588176};


3. Calculated the time delay dt using the following formula;
  dt = [pm - pc]/f/360deg    (pm: measured phase, pc: calculated phase from feCoeff4x, f: frequency)

4. Measured TF between the SCSI cables to estimate the effect of the cables and others.
  Disconnected SCSI cables from ADC and DAC, and connected A aad B(see setup).
  I measured both when input coupling of SR785 is DC and AC and see what happens.

Result:
  [time delay of the CDS]  (left, middle)
    The time delay gets larger with frequency. The time delay seems to be -175 usec at DC.
    However, the gain seems a little different from my expectation(feCoeff4x). So, there are maybe other filters I don't know.
    I neglected TF of upsampling this time.

  [cable and other effect]  (right)
    The effect to the time delay measurement was tiny by a factor of 10^4 to 10^3 (few nsec).
    But the total cable length was about 5 m and assuming signal speed is 0.6c, delay will be about 30 nsec.
    I don't know what's happening.

CDSdelay.png

Plan:
  - make a model that does not go through IOP and see the delay caused by IOP

By the way:
  fb daqd is still running for hours!
  Every FEs are running(c1sus,rms,mcs).

  3830   Sat Oct 30 14:35:43 2010 KojiSummaryCDSCDS time delay measurement

Unsatisfactory.

Neglecting the digital anti-imaging filter makes the discrepancy. You must take into account your digital filter twice.

I attached the slides I made during my visit for March LVC '09. P.5 would be useful.

Quote:

Result:
  [time delay of the CDS]  (left, middle)
    The time delay gets larger with frequency. The time delay seems to be -175 usec at DC.
    However, the gain seems a little different from my expectation(feCoeff4x). So, there are maybe other filters I don't know.
    I neglected TF of upsampling this time.

 

Attachment 1: CDS_system_investigation_090323.pdf
CDS_system_investigation_090323.pdf CDS_system_investigation_090323.pdf CDS_system_investigation_090323.pdf CDS_system_investigation_090323.pdf CDS_system_investigation_090323.pdf CDS_system_investigation_090323.pdf CDS_system_investigation_090323.pdf CDS_system_investigation_090323.pdf
  3831   Sun Oct 31 00:19:35 2010 ranaSummaryComputer Scripts / ProgramsHP3563A netGPIB function

I've wheeled the old HP audio frequency signal analyzer into the control room to debug the GPIB/python interface. The wireless setup was getting more than 80% packet loss in the office area.

I also noticed that we have multiple and competing copies of the netgpib package installed. Kiwamu is going to merge them soon. Pleae only use the official location:

scripts/general/netgpibdata/

which is also the SVN working copy. Committ all changes periodicallty so that we can share the updated versions between sites.

  3838   Mon Nov 1 15:47:15 2010 yutaSummaryCDSCDS time delay measurement

Background:
  I measured CDS time delay last week, but because of my lack of understanding the system, it was incorrect.
  IOP has an anti-aliasing filter before downsampling from 64kHz(65536Hz) to 16kHz(16384Hz) and also has an anti-imaging filter before upsampling from 16kHz to 64kHz.
  So, I should have take feCoeff4x into account twice.
downupsampling.png

Result:
  TF agreed well with 2-time feCoeff4x and CDS time delay was -123.5 usec.
CDSdelay2.png


Plan:
 - make AWG(, diaggui TF measurement, tdssine) work
 - check input/output filter switching (using tdssine & tdsdmd)
 - measure openloop TF of MC suspension damping
 - divide it with my expectation and see if there are any filters I don't know

Quote:

Unsatisfactory.

Neglecting the digital anti-imaging filter makes the discrepancy. You must take into account your digital filter twice.

I attached the slides I made during my visit for March LVC '09. P.5 would be useful.

 

  3839   Mon Nov 1 16:43:24 2010 KojiSummaryCDSCDS time delay measurement

Um, Beautiful.

Actually, 123.5usec is almost exactly twice of 1/16384Hz.
Because of the loop, we have 1/16384Hz delay. I wonder where we do have the delay.

In order to understand the behaviour of the system can I ask you to test the following things?

1) What are the delay without IOPs with fsampl of 16k, 32k, 64k?

2) What are the delay with IOP with fsampl of 32k, 64k?

Quote:

Result:
  TF agreed well with 2-time feCoeff4x and CDS time delay was -123.5 usec.
CDSdelay2.png

 

  3841   Mon Nov 1 19:32:08 2010 yutaSummaryCDSfb crashed? during c1ioo and c1mcs connection at ASC

Frame builder died again!!

Background:
  We want to do angle to length measurement to optimize the beam position and increase visibility of MC locking.
  In order to do A2L measurement, we need excitation point, but AWG is currently not working.
  The better way is to use LOCKIN stuff like we had for OMC and put it to C1IOO WFS.
  A software oscillator in LOCKIN shakes the suspension, and demodulate the length signal.
  We can choose whatever DOF to shake, whatever signal to demodulate. It would be useful not just for A2L.

What I did:

  I started to put C1IOO WFS signal into C1SUS MC suspension RT model, but after compiling new c1mcs, fb crashed.
  Looks like daqd and mx_streams are running, but DAQ is not working(red).
  I don't know how to restart in a new way!

  3849   Wed Nov 3 02:23:11 2010 yutaSummaryCDSchecking whitening filter board

Summary:
  Last night, I found that some of the input channels have wrong hardware filter switching(see elog #3842).
  So, to check the whitening board(D000210), I swapped the one with ok switching and bad switching.
  During the checking, I somehow broke the board.
  I fixed it, and now the status is the same as last night (or, at least look like the same).

What I did:
  1. Switching for SRM_LRSEN looked bad and every input channel for MC3 looked OK.
     So, I unplugged the whitening board for SRM (1X5-1-5B) and plugged it into MC3's place(1X5-1-8B).

  2. Ran WDWchecker.py for MC3. The switching seemed OK for every input channel, which means the whitening board was not the wrong one.

  3. Swapped back the whitening board as it was.

  4. Found MC3_ULSEN_OUT and MC3_LLSEN_OUT was keep showing negative value(they should be positive).

  5. Check the board and found that one of LT1125 for UL/LL was wrong (broken virtual ground).

  6. Replaced LT1125 and put the board back to 1X5-1-8B.

  7. Checked the board with WDWchecker.py and dataviewer 5-hour minute trend.
      The input signal came back to normal value(Attachment #1), MC3 damping working, input filter switching seems working

before LT1125 replacement after LT1125 replacement
C1:SUS-MC3_ULSEN_IN1: -2.4 dB [!]
C1:SUS-MC3_URSEN_IN1: 16.9 dB
C1:SUS-MC3_LRSEN_IN1: 15.4 dB
C1:SUS-MC3_LLSEN_IN1: -1.1 dB [!]
C1:SUS-MC3_SDSEN_IN1: 18.4 dB
C1:SUS-MC3_ULSEN_IN1: 18.2 dB
C1:SUS-MC3_URSEN_IN1: 17.6 dB
C1:SUS-MC3_LRSEN_IN1: 16.6 dB
C1:SUS-MC3_LLSEN_IN1: 17.1 dB
C1:SUS-MC3_SDSEN_IN1: 16.2 dB


Result:
  The whitening board seems OK.
  The wrong one is either wiring or RT model. Or, the checking script.

Attachment 1: MC3SEN.png
MC3SEN.png
  3850   Wed Nov 3 02:37:39 2010 yutaSummaryGreen Lockingcoarse locked green beat frequency

(Kiwamu, Yuta)

We succeeded in coarse locking the green beat frequency, using a frequency counter and feeding back the signal to the X-end laser temperature.

Setup:
  beat note -> RF PD -> SHP-25 -> SLP-100 -> ZFL-1000LN -> ZFL-1000LN -> ZFL-500LN -> ZFRSC-42 -> SBP-70 -> ZFRSC-42 -> SR620 -> c1psl(C1:PSL-126MOPA_126MON)
  c1auxey(C1:LSC-EX_GREENLASER_TEMP) -> X-end laser temp

  The frequency counter SR620 converts the beat frequency to voltage.
  We added some filters (SHP-25, SLP-100, SBP-70). Otherwise, SR620 doesn't count the frequency correctly.

What we did:

  1. Getting green beat note again
     Set PSL laser temp to 31.81 °C and X-end laser temp to 37.89 °C.
     Set PPKTP crystal temp to 37.6 °C, which maximizes output green beam power.

  2. ADC channel and DAC channel
     Disconnected one channel going into VME-3123 (at 1X1) and used c1psl's C1:PSL-126MOPA_126MON as ADC channel for the output from SR-620
     Made a new DAC channel on c1auxey named C1:LSC-EX_GREENLASER_TEMP, and disconnected one channel from VME-4116 (at 1X9) to use it as DAC channel for X-end laser temperature control.

  3. Coarse lock by ezcaservo
     Ran;
        ezcaservo C1:PSL-126MOPA_126MON -s 150 -g -0.0001 C1:LSC-EX_GREENLASER_TEMP
     "-s" option is a set value. The command locks C1:PSL-126MOPA_126MON to 150 (in counts), using 0Hz pole integrator.

Result:
  The beat frequency locked on to ~77MHz. The frequency fluctuation of the beat note during the servo is ~3MHz with ~10sec timescale.
  VCO has  ~+/-5MHz range, so this coarse locking meets the requirement.

  Here's a plot of the error signal and feed back signal;
  Screenshot_LowFreqLock.png

  3851   Wed Nov 3 03:00:47 2010 KojiSummaryGreen Lockingcoarse locked green beat frequency

Wow! Great guys!!

Can I expect to see the spectra of the frequency counter output with and without the servo?

RA: I think the SBP-70 is a bad idea. It limits the capture range. So does the SHP-25. You should instead just use a DC-block; the SR620 should work from 1-200 MHz with no problems.

Also, we have to figure out a better solution for the DAC at the ends: we cannot steal the QPD gain slider in the long run and the 4116 DAC at the ends has all 8 channels used up. Should we get the purple box for testing or should we try to use the fast DAC in the EX IO chassis as the actuator?

  3852   Wed Nov 3 09:32:00 2010 ranaSummaryCDSEurocard board swapping

When swapping Eurocard boards, it is safest to first turn down the power supplies and then do the swapping.

Otherwise, it is sometimes the case that people plug in the board slowly and/or asymmetrically. This can cause the opamp to see one of the power supply rails without the other (e.g. +15 but not -15).

This can destroy some opamps. The true danger is that there may be damage to the board which you do not notice for several months, thereby leaving a timebomb for the next person.

Don't be an electronics terrorist!

  3855   Wed Nov 3 17:01:01 2010 josephbSummaryCDSComparison of RFM read times

Problem:

RFM reads are slow.  Rolf has said it should take 2-3 microseconds per read. 

c1sus is taking about 7 microseconds per read, twice as slow as Rolf's claim.

Hypothesis:

The RFM card is in the IO chassis, and is sharing the PCIe bus with 4 ADC cards, 3 DAC cards, 4 BO cards, and a BIO card.  Its possible this crowded bus is causing the reads to take even longer.

Test Results:

Compare read times between the c1sus computer, which has its RFM card in the IO chassis, to c1ioo, which has its RFM card in the computer.

c1ioo:

No RFM reads: 8 microseconds

3 RFM reads: 20 microseconds (~4 per read)

6 RFM reads: 32 microseconds (~4 per read)

c1sus:

No RFM read: 25 microseconds (bigger model)

1 RFM read: 33 microseconds (~8 per read)

3 RFM read: 45 microseconds (~7 per read)

6 RFM read: Over 62 microseconds, doesn't run.

Conclusion:

It looks like moving the RFM card may help by about a factor of 2 in read speed, although its still not quite what Alex and Rolf claim it should be.

The c1mcs and c1ioo models have been reverted to their normal operations.

 

  3869   Fri Nov 5 15:20:18 2010 josephb, alexSummaryCDS40m computer slow down solved

Problem:

The 40m computers were responding sluggishly yesterday, to the point of being unusable.

Cause:

The mx_stream code running on c1iscex (the X end suspension control computer) went crazy for some reason.  It was constantly writing to a log file in /cvs/cds/rtcds/caltech/c1/target/fb/192.168.113.80.log.  In the past 24 hours this file had grown to approximately 1 Tb in size. The computer had been turned back on yesterday after having reconnected its IO chassis, which had been moved around last week for testing purposes - specifically plugging the c1ioo IO chassis in to it to confirm it had timing problems.

Current Status:

The mx_stream code was killed on c1iscex and the 1 Tb file removed.

Computers are now more usable.

We still need to investigate exactly what caused the code to start writing to the log file non-stop.

Update Edit:

Alex believes this was due to a missing entry in the /diskless/root/etc/hosts file on the fb machine.  It didn't list the IP and hostname for the c1iscex machine.  I have now added it.  c1iscex had been added to the /etc/dhcp/dhcpd.conf file on fb, which is why it was able to boot at all in the first place.  With the addition of the automatic start up of mx_streams in the past week by Alex, the code started, but without the correct ip address in the hosts file, it was getting confused about where it was running and constantly writing errors.

Future:

When adding a new FE machine, add its IP address and its hostname to the /diskless/root/etc/hosts file on the fb machine.

  3872   Fri Nov 5 21:49:12 2010 ranaSummaryCDS40m computer slow down solved

Quote:

Problem:

The 40m computers were responding sluggishly yesterday, to the point of being unusable.

Cause:

The mx_stream code running on c1iscex (the X end suspension control computer) went crazy for some reason.  It was constantly writing to a log file in /cvs/cds/rtcds/caltech/c1/target/fb/192.168.113.80.log.  In the past 24 hours this file had grown to approximatel

The moral of the story is, PUT THINGS IN THE ELOG. This wild process is one of those things where people say 'this won't effect anything', but in fact it wastes several hours of time.

  3875   Sat Nov 6 01:54:15 2010 FrankSummaryComputersvirus definition file update on laptop for dinocam

i took some pictures with the dinocam this afternoon. I used the laptop computer next to it using wireless lan connection to the caltech network to send the pictures to me.

The installed anti virus software was bitching about the old database and wanted to update that. As the installed virus definition database was from mid last year i agreed and started downloading the update. As the file was huge (~100MB) it wasn't finished when i left. computer is still running and probably waiting for instructions.

Will come back on the weekend to finalize the new virus definition file database installation.

  3876   Sat Nov 6 07:26:54 2010 yutaSummaryIOOreduced common mode displacement of the beam through MC1 to MC3

(Koji, Suresh, Yuta)

Summary:

  We need MC to be locked and aligned well to align other in-vac optics.
  By using a new python script A2L.py(see elog #3863), we are measuring A2L coupling and centering the beam.
  Tonight's goal was to reduce common mode displacement of the beam through MC1 to MC3, and we succeeded.

Strategy of beam centering:

  We first ignore the beam position at MC2 and focus on MC1,MC3. If MC1,MC3 alignments are given, MC2 alignment is determined.

  For MC1 and MC3, we first reduce the common mode displacement using the last steering mirror at PSL table.
  The last steering mirror makes translation of the incident beam because it is far (~m) from the MC.
  So,
    1. Rotate the steering mirror nob a little
    2. Lock MC so that MC beam axis will be the same as the incident beam axis
    3. A2L measurement
    4. To 1-3 over until the beam crosses MC1 center to MC3 center axis
        The amount of vertical/horizontal displacements of the beam spot at MC1 and MC3 should be the same.
        From our convention, for vertical, MC1 and MC3 should have opposite sign. For horizontal, same sign. (see picture below)

Result:
A2LMCalign.png
 
  From the A2L measurement, now the beam spot is lower right at MC1 and upper right at MC3.
 

  The directions of the beam spot motion agree with the steering mirror tilts.
  Also, the amount of the motion seems reasonable.
    1 tooth rotation of the steering mirror nob makes ~1e-3 inch push which equals to ~0.5mrad rotation.
    The steering mirror to MC is like ~2m and 0.5mrad mirror tilt makes ~2mm displacement at the MC optics.
    2mm displacement is ~15% at the mirror (see Koji's elog #2863;note that coil-coil distance is 1/sqrt(2) of the mirror diameter).
    The measured vertical spot motion is ~15%/1tooth. Horizontal is sqrt(2) times bigger because of the angle of the MC1, MC3 and they are about that much, too.

Plan:
 - Use IM1 to make beam tilt and finally center the beam
 - Improve the script so that it features weighting in fitting
 - Write a script that balances actuation efficiency of the 4 coils.
     We are currently assuming that 4 coils are well balanced.
     In order to do the balancing, we need to balance OSEMs too.

  3877   Sat Nov 6 16:13:14 2010 ranaSummaryCDS40m computer slow down solved

As part of the effort to debug what was happening with the slow computers, I disabled the auto MEDM snapshots process that Yoichi/Kakeru setup some long time ago:

https://nodus.ligo.caltech.edu:30889/medm/screenshot.html

We have to re-activate it now that the MEDM screen locations have been changed. To do this, we have to modify the crontab on nodus and also the scripts that the cron is calling. I would prefer to run this cron on some linux machine since nodus starts to crawl whenever we run ImageMagick stuff.

Also, we should remember to start moving the old target/ directories into the new area. All of the slow VME controls are still not in opt/rtcds/.

  3883   Tue Nov 9 05:40:12 2010 yutaSummaryIOOMC aligning going on

(Suresh, Yuta)

Background:
  Last week, we reduced the common mode displacement of the beam through MC1 to MC3. 
  Next work is to tilt the beam and center it.

What we did:
  1. Changed the offset going into 1201 Low Noise Amplifier(1201 is for adding +5V offset so that the feedback signal will be in the range of 0-10V)
  2. Using the last steering mirror(SM@PSL) and IM1, tilted the beam
  3. As the beam height changed alot(~0.5cm higher at IM1), MC1 reflection could not reach MCREFL PD. So, we tilted the mirror just after MC1, too.

Result:
MCalignNov9.png

Plan:

  - continue to tilt IM1 in small increments in order to reduce PIT/YAW to length coupling
      If large increments, it takes so much time re-aligning MC to get flashing!

By the way:

    The signal we kept saying "MCL" was not the error signal itself. It was a feed back signal(output of the mode cleaner servo board). The cable labeled "MC REFL" is the error signal. Compare MEDM screen C1IOO_MC_SERVO.adl and the mode cleaner servo board at 1X2. You will be enlightened.

Quote (from elog #3857):

4. Disconnected the cable labeled "MC OUT1" at 1X2 (which is MCL signal to ADC) and put MC2_ULCOIL output directly using long BNC cable.

 

  3884   Wed Nov 10 02:51:35 2010 yutaSummaryIOOlimitation of current MC aligning

(Suresh, Yuta)

Summary:
  We need MC to be locked and aligned well to align other in-vac optics.
  We continued to align the incident beam so that the beam passes the actuation nodes of MC1 and MC3.
  From the previous measurement, we found that beam height at IM1 has to be increased by ~3cm.
  Today, we increased it by ~1cm and achieved about 1/3 of the required correction.
  But we cannot proceed doing this because the beam is hitting IM1 at the edge already.

What is the goal of this alignment?:
  If the beam doesn't hit MC optics in the center, we see angle to length coupling, which is not good for the whole interferometer.
 
  Also, if the beam is tilted so much, transmitted beam though MC3 cannot go into FI at right after MC3.
  Say, FI has an aparture of 3mm and MC3-FT distance is 300mm. The beam tilt should be smaller than 3/300 rad. MC1-MC3 distance is 200mm, so the displacement at each mirror should be smaller than ~1mm.
  1mm is about 7% (see Koji's elog #2863) TO_COIL gain imbalance in A2L measurement.
 
  We are currently assuming that each coils are identical. If they have 5% variance, it is meaningless to try to reduce the beam displacement less than ~5%.

  So, we set the goal to 7%.

What we did:

  1. Leveled the MC table.

  2. Measured the table height using DISTO D3 laser gauge.
    PSL table 0.83m (+-0.01m)
    OMC table 0.82m
    MC table  0.81m

  3. Using the last steering mirror(SM@PSL) and IM1, tilted the beam vertically

Result:

MCalignNov9.png

  At t=0 (this morning), the beam tilt was ~40%/(MC1-MC3 distance). Now, it is ~30%/(MC1-MC3 distance).
  30%/(MC1-MC3 distance) is ~5/200 rad.

Plan:

 We have to somehow come up with the next story. Too much vertical tilt. What is wrong? Table leveling seems OK.
 - measure in-vac beam height
 - maybe OSEMs are badly aligned. we have to check that.

  3885   Wed Nov 10 11:46:19 2010 KojiSummaryIOOlimitation of current MC aligning

It didn't make sense in several points.

1. Is the Faraday aperture really 3mm? The beam has the gaussian radius of ~1.5mm. How can it be possible to go through the 3mm aperture?

2. Why the MC3-FT distance is the matter? We have the steering mirror after MC3. So we can hit the center of the Faraday.
But if we have VERTICAL TILT of the beam, we can not hit the center of the Faraday entrance and exit at the same time.
That would yield the requirement.

3. If each coil has 5% variance in the response, variance of the nodal point (measured in % of the coil imbalance) by those four coils will be somewhat better than 5%, isn't it?

  3886   Wed Nov 10 12:21:18 2010 yutaSummaryIOOlimitation of current MC aligning

1. We didn't measure the aperture size last night. We have to check that.

2. We have to measure the length of FI. Or find a document on this FI.

3. Yes, 5%/sqrt(4). But I didn't think the factor of 2 is important for this kind of estimation.

  3887   Wed Nov 10 14:28:33 2010 KojiSummaryIOOlimitation of current MC aligning

1. Look at the Faraday.

2. Look at the wiki. There is the optical layout in PNG and PDF.

3. 5% (0.8mm) and 2.5%(0.4mm) sounds a big difference for the difficulty, but if you say so, it is not so different.

Actualy, if you can get to the 5% level, it is easy to get to the 1-2% level as I did last time.
The problem is we are at the 15-20% level and can not improve it.

  3891   Thu Nov 11 04:32:53 2010 yutaSummaryCDSfound poor contact of DAC cable, previous A2L results were wrong

(Koji, Jenne, Yuta)

We found one of DAC cables had a poor contact.
That probably caused our too much "tilt" of the beam into MC.

Story:
  From the previous A2L measurement and MC aligning, we found that the beam is somehow vertically "tilted" so much.
  We started to check the table leveling and the beam height and they looked reasonable.
  So, we proceeded to check coil balancings using optical levers.
  During the setup of optical levers, I noticed that VMon for MC1_ULCOIL was always showing -0.004 even if I put excitation to coils.
  It was because one of the DAC cables(labeled CAB_1Y4_88) had a poor contact.
  If I push it really hard, it is ok. But maybe we'd better replace the cable.

What caused a poor connection?:
  I don't know.
  A month ago, we checked that they are connected, but things change.

How to prevent it:
  I made a python script that automatically checks if 4 coils are connected or not using C1:IOO_LOCKIN oscillator.
  It is /cvs/cds/caltech/users/yuta/scripts/coilchecker.py.
  It turns off all 3 coils except for the one looking at, and see the difference between oscillation is on and off.
  The difference can be seen by demodulating SUSPOS signal by oscillating frequency.
  If I intentionally unplug CAB_1Y4_88, the result output for MC1 will be;

==RESULTS== (GPS:973512733)
MC1_ULCOIL      0.923853382664 [!]
MC1_URCOIL      38.9361304794
MC1_LRCOIL      55.4927575177
MC1_LLCOIL      45.3428533919


Plan:
 - Make sure the cable connection and do A2L and MC alignment again
 - Even if the cables are ok, it is better to do coil balancings. See the next elog.

  3892   Thu Nov 11 05:56:04 2010 yutaSummaryIOOsetting up temporary oplev for coil balancing of MCs

(Suresh, Yuta)

Background:
  Previous A2L measurement is based on the assumption that actuator efficiencies are identical for all 4 coils.
  We thought that the unbelievable "tilt" may be caused by imbalance of the coils.

Method:
  1. Setup an optical lever.
  2. Dither the optic by one coil and demodulate oplev outputs(OL_PIT or OL_YAW) in that frequency.
  3. Compare the demodulated amplitude. Ideally, the amplitude is proportional to the coil actuation efficiency.

What we did:
[MC2]
  MC2 is the least important, but the easiest.
  1. Placed a red laser pointer at MC2 trans table. During the installation, I moved the mirror just before QPD.
  2. Made a python script that measures coil actuation efficiency using the above method. I set the driving frequency to 20Hz.
  It is /cvs/cds/caltech/users/yuta/scripts/actuatorefficiency.py.
  The measurement result is as follows. Errors are estimated from the repeated measurement. (Attachment #1)

MC2_ULCOIL 1
MC2_URCOIL 0.953 ± 0.005
MC2_LRCOIL 1.011 ± 0.001
MC2_LLCOIL 0.939 ± 0.006


[MC1]
  For MC1, we can use the main laser and WFS1 QPD as an oplev.
  But we only have slow channels for QPD DC outputs(C1:IOO_WFS1_SEG#_DC).
  So, we intentionally induce RF AM by EOM(see Kiwamu's elog #3888) and use demodulated RF outputs of the WFS1 QPD(C1:IOO_WFS1_I/Q#) to see the displacement.
  1. Replaced HR mirror in the MCREFL path at AP table to BS so that we can use WFS1.(see Koji's elog #3878)
    The one we had before was labeled 10% pick-off, but it was actually an 1% pick-off.
  2. Checked LO going into WFS1 demodulator board(D980233 at 1X2).
    power: 6.4dBm, freq: 29.485MHz
  3. Turned on the hi-voltage(+100V) power supply going into the demodulator boards.
  4. Noticed that no signal is coming into c1ioo fast channels.
    It was because they were not connected to fast ADC board. We have to make a cable and put it in.

[MC3]
  Is there any place to place an oplev?

Plan:
 - prepare c1ioo channels and connections
 - I think we'd better start A2L again than do oplev and coil balancing.

Attachment 1: MC2coils.png
MC2coils.png
  3895   Thu Nov 11 11:51:30 2010 KojiSummaryCDSfound poor contact of DAC cable, previous A2L results were wrong

The cause is apparent! The connectors on the cables are wrong!
Currently only 50% of the pin length goes into the connector!

Quote:

(Koji, Jenne, Yuta)

We found one of DAC cables had a poor contact.
That probably caused our too much "tilt" of the beam into MC.

  It was because one of the DAC cables(labeled CAB_1Y4_88) had a poor contact.
  If I push it really hard, it is ok. But maybe we'd better replace the cable.

What caused a poor connection?:
  I don't know.
  A month ago, we checked that they are connected, but things change.

 

  3901   Thu Nov 11 23:35:23 2010 KojiSummaryCDSfound poor contact of DAC cable, previous A2L results were wrong

[Koji / Yuta]

There were the guys who used the PENTEK 40pin connectors into the IDC 40pin connectors.
Those connectors are not compatible at all.

==> We replaced the connectors on the cables from DAC to IDC adapters to the dewhitening board for the vertex SUSs.

In addition, I found one of the Binary OUT IDC50pin connector has no clamp.

==> We put the IDC50pin clamp on it.

bad-boys.png

PENTEK connectors were inserted. The latches are not working!

IMG_3698.jpg

the vertical pitch is different between PENTEK and IDC!
IMG_3705.jpg

Wow! Where is the clamp???

IMG_3706.jpg

Quote:

The cause is apparent! The connectors on the cables are wrong!
Currently only 50% of the pin length goes into the connector!

Quote:

(Koji, Jenne, Yuta)

We found one of DAC cables had a poor contact.
That probably caused our too much "tilt" of the beam into MC.

  It was because one of the DAC cables(labeled CAB_1Y4_88) had a poor contact.
  If I push it really hard, it is ok. But maybe we'd better replace the cable.

What caused a poor connection?:
  I don't know.
  A month ago, we checked that they are connected, but things change.

 

 

  3924   Mon Nov 15 15:02:00 2010 KojiSummaryPSLpower measurements around the PMC

[Valera Yuta Kiwamu Koji]

Kiwamu burtrestored c1psl. We measured the power levels around the PMC.

With 2.1A current at the NPRO:

Pincident = 1.56W
Ptrans_main = 1.27W
Ptrans_green_path = .104W

==> Efficiency =88%

----

We limited  the MC incident power to ~50mW. This corresponds to the PMC trans of 0.65V.
(The PMC trans is 1.88V at the full power with the actual power of 132mW)

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