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ID Date Author Type Category Subject
  1781   Wed Jul 22 20:11:26 2009 peteUpdateComputersRCG front end

I compiled and ran a simple (i.e. empty) front end controller on scipe12 at wilson house.  I hooked a signal into the ADC and watched it in the auto-generated medm screens. 

There were a couple of gotchas:

1. Add an entry SYS to the file /etc/rc.local, to the /etc/setup_shmem.rtl line, where the system file is SYS.mdl.

2. If necessary, do a BURT restore.  Or in the case of a mockup set the BURT Restore bit (in SYS_GDS_TP.adl) to 1.

 

  1780   Wed Jul 22 18:04:14 2009 robOmnistructureComputersweird noise coming from Gigabit switch

in the rack next to the printer.  It sounds like a fan is hitting something.

  1779   Wed Jul 22 16:15:52 2009 Chris ZimmermanUpdateGeneralWeek 5/6 Update

The last week I've started setting up the HeNe laser on the PSL table and doing some basic measurements (Beam waist, etc) with the beam scan, shown on the graph.  Today I moved a few steering mirrors that steve showed me from at table on the NW corner to the PSL table.  The goal setup is shown below, based on the UCSD setup.  Also, I found something that confused me in the EUCLID setup, a  pair of quarter wave plates in the arm of their interferometer, so I've been working out how they organized that to get the results that they did.  I also finished calculating the shot noise levels in the basic and UCSD models, and those are also shown below (at 633nm, 4mw) where the two phase-shifted elements (green/red) are the UCSD outputs, in quadrature (the legend is difficult to read).

 

 

Attachment 1: Beam_Scan.jpg
Beam_Scan.jpg
Attachment 2: Long_Range_Michelson_Setup_1_-_Actual.png
Long_Range_Michelson_Setup_1_-_Actual.png
Attachment 3: NSD_Displacement.png
NSD_Displacement.png
  1778   Wed Jul 22 14:44:57 2009 ZachUpdateCamerasGigE Phase Camera

This past week, I have mostly been debugging my software.  I have tried to use the fluorescent lights to test the camera, but I can't tell for sure if my code is finding the correct amplitude and phase or not.  I am currently using Mathematica to double check my calculations in solving for the phase and amplitude.

Also, I have taken dark field images using a lens with a closed shutter.  I have found that the dark band across the top of the images only appears after the camera heats up.  Also, there is an average electronic noise of 14 with a maximum of 40.  However, this electronic noise as well as any consistent ambient noise will be automatically corrected for in the calculations I'm using because I'm taking the differences between the CCD images to calculate relative phases and amplitudes.

I should be able to start setting up optics and performing better tests of my software this week.

  1777   Wed Jul 22 11:18:49 2009 robConfigurationComputerssticky sliders

Quote:

Quote:

Quote:

Quote:

All suspentions are kicked up. Sus dampings and  oplev servos turned off.

c1iscey and c1lsc are down. c1asc and c1iovme are up-down

 The computers and RFM network are up working again. A boot fest was necessary.Then I restored all the parameters with burtgooey.

The mode cleaner alignment is in a bad state. The autolocker can't get it locked. I don't know what caused it to move so far from the good state that it was till this afternoon.  I went tuning the periscope but the cavity alignment is so bad that it's taking more time than expected. I'll continue working on that tomorrow morning.

 I now suspect that after the reboot the MC mirrors didn't really go back to their original place even if the MC sliders were on the same positions as before.

 Alberto, Rob,

we diagnosed the problem. It was related with sticky sliders. After a reboot of C1:IOO the actual output of the DAC does not correspond anymore to the values read on the sliders. In order to update the actual output it is necessary to do a change of the values of the sliders, i.e. jiggling a bit with them.

 I've updated the slider twiddle script to include the MC alignment biases.  We should run this script whenever we reboot all the hardware, and add any new sticky sliders you find to the end of the script.  It's at

 

/cvs/cds/caltech/scripts/Admin/slider_twiddle

  1776   Wed Jul 22 11:14:11 2009 AlbertoConfigurationComputerscomputers are down

Quote:

Quote:

Quote:

All suspentions are kicked up. Sus dampings and  oplev servos turned off.

c1iscey and c1lsc are down. c1asc and c1iovme are up-down

 The computers and RFM network are up working again. A boot fest was necessary.Then I restored all the parameters with burtgooey.

The mode cleaner alignment is in a bad state. The autolocker can't get it locked. I don't know what caused it to move so far from the good state that it was till this afternoon.  I went tuning the periscope but the cavity alignment is so bad that it's taking more time than expected. I'll continue working on that tomorrow morning.

 I now suspect that after the reboot the MC mirrors didn't really go back to their original place even if the MC sliders were on the same positions as before.

 Alberto, Rob,

we diagnosed the problem. It was related with sticky sliders. After a reboot of C1:IOO the actual output of the DAC does not correspond anymore to the values read on the sliders. In order to update the actual output it is necessary to do a change of the values of the sliders, i.e. jiggling a bit with them.

  1775   Wed Jul 22 11:08:36 2009 StephanieUpdateGeneralMultiply Resonant EOM Update

I have built a version of the circuit with flying components; the completed circuit is shown in the attached picture. I built the circuit in segments and measured the transfer function after each segment to see whether it matched the LTSpice simulation after each step. The segments are shown in the circuit diagram.

After building the first segment, the measured transfer function looked pretty much the same as the simulated transfer function; it appears shifted in the attached plot, but this is because I didn't do a careful job of tuning at this point, and I'm relatively sure that I could have tuned it to match the simulation. After adding the second segment of the circuit, the measured and simulated transfer functions were similar in shape, but I was unable to increase the frequency of the peaks (through tuning) any more than what is shown in the plot (I could move the peaks so that their frequency was lower, but they are shown as high as they will go). When I added the final segment to complete the circuit, the measured and simulated transfer functions no longer had the same shape; two of the peaks were very close together and I was barely able to differentiate one from the other.

In order to understand what was happening, I tried making modifications to the LTSpice model to recreate the transfer function that was measured. I was able to create a transfer function that closely resembles the measured transfer function in both the circuit as of the 2nd segment and the completed circuit by adding extra inductance and capacitance as shown in red in the circuit diagram. The transfer functions simulated with these parasitic components are shown in red in both plots. While I was able to recreate the response of the circuit, the inductance and capacitance needed to do this were much larger than I would expect to occur naturally within the circuit (2.2uH, 12 pF). I'm not sure what's going on with this.

Attachment 1: BuiltCkt_Picture.png
BuiltCkt_Picture.png
Attachment 2: BuiltCkt2_Final.png
BuiltCkt2_Final.png
Attachment 3: 1stSegment.png
1stSegment.png
Attachment 4: 2ndSegment_ExtraL.png
2ndSegment_ExtraL.png
Attachment 5: Complete_ExtraL.png
Complete_ExtraL.png
  1774   Wed Jul 22 10:49:40 2009 AlbertoUpdatePSLMC Alignment Trend

Trying to track the MC positions back for a few days, it seems that the data hasn't been recorded properly for a while. Something happened yesterday after my boot fest and then the record got restored. Attached here are the readbacks showing the event for MC1.

Is anything wrong with the data record?

Attachment 1: 2009-07-21_MC-align-trend.pdf
2009-07-21_MC-align-trend.pdf
Attachment 2: 2009-07-22_mc-align-trend.pdf
2009-07-22_mc-align-trend.pdf
  1773   Wed Jul 22 09:04:10 2009 AlbertoConfigurationComputerscomputers are down

Quote:

Quote:

All suspentions are kicked up. Sus dampings and  oplev servos turned off.

c1iscey and c1lsc are down. c1asc and c1iovme are up-down

 The computers and RFM network are up working again. A boot fest was necessary.Then I restored all the parameters with burtgooey.

The mode cleaner alignment is in a bad state. The autolocker can't get it locked. I don't know what caused it to move so far from the good state that it was till this afternoon.  I went tuning the periscope but the cavity alignment is so bad that it's taking more time than expected. I'll continue working on that tomorrow morning.

 I now suspect that after the reboot the MC mirrors didn't really go back to their original place even if the MC sliders were on the same positions as before.

  1772   Wed Jul 22 01:57:19 2009 AlbertoConfigurationComputerscomputers are down

Quote:

All suspentions are kicked up. Sus dampings and  oplev servos turned off.

c1iscey and c1lsc are down. c1asc and c1iovme are up-down

 The computers and RFM network are up working again. A boot fest was necessary.Then I restored all the parameters with burtgooey.

The mode cleaner alignment is in a bad state. The autolocker can't get it locked. I don't know what caused it to move so far from the good state that it was till this afternoon.  I went tuning the periscope but the cavity alignment is so bad that it's taking more time than expected. I'll continue working on that tomorrow morning.

  1771   Tue Jul 21 18:46:47 2009 steveConfigurationComputerscomputers are down

All suspentions are kicked up. Sus dampings and  oplev servos turned off.

c1iscey and c1lsc are down. c1asc and c1iovme are up-down

  1770   Tue Jul 21 17:52:12 2009 JenneUpdateIOOMC_L flatlined

Quote:

[Clara, Jenne]

While Clara was working on her Wiener filtering and optimizing the locations of the accelerometers, she discovered that MC_L and MC_L_256 are totally flatlined.  I looked at them, and it looks like they've been dead since ~9:30pm-ish on Sunday night.  Bootfest-type activities shall commence shortly.

 Under Alberto's tutalage, I rebooted the whole vme set (iovme, sosvme, susvme1, susvme2), and after that MC_L was all good again.

  1769   Tue Jul 21 17:01:18 2009 peteDAQDAQtemp channel PEM-PETER_FE

I added a temporary channel, to input 9 on the PEM ADCU.    Beware the 30, 31, and 32 inputs.  I tried 32 and it only gave noise.

 

 

  1768   Tue Jul 21 15:32:47 2009 JenneUpdateIOOMC_L flatlined

[Clara, Jenne]

While Clara was working on her Wiener filtering and optimizing the locations of the accelerometers, she discovered that MC_L and MC_L_256 are totally flatlined.  I looked at them, and it looks like they've been dead since ~9:30pm-ish on Sunday night.  Bootfest-type activities shall commence shortly.

  1767   Tue Jul 21 13:55:08 2009 ClaraUpdatePEMGuralp Box Success!

There managed to be just enough 100 kOhm resistors to stuff all the "2" channels (VERT2, N/S2, E/W2) with the fancy low-noise resistors. The first six channels (VERT 1/2, NS 1/2, EW 1/2) are now completely done with the thin-film resistors, taking into account the changes that were made on the circuit diagram. I also replaced the C8 capacitor with the fancy Garrett ones and added capacitors on top of R4 and R13 (after painstakingly making sure that the capacitances are exactly the same for each pair) for the "2" channels. It looks like the capacitors on the "1" channels are the cheaper ones. I will compare the noise measurements later to see if there is any difference - if so, I can replace those as well (although, we're out of the 1 uF capacitors needed for C8).

Speaking of, we are now out of or very low on several types of the Garrett resistors/capacitors: 1 uF, 1kOhm, 100 Ohm, 14.0 Ohm, and 100 kOhm. I left the specifics on Steve's desk so that more can be ordered for the eventual time when the third set of channels needs to be restuffed.

  1766   Tue Jul 21 01:11:30 2009 DmassAoGComputersAlarms going off

I came into the 40m to sign things out briefly then swiftly return them, and the alarms were going off on op540m at 1am.

 

The cat and donkey? were making much noise.

  1765   Mon Jul 20 17:06:29 2009 JenneUpdatePEMGuralp Box Fail

Quote:
That's terrible: R5 & R8 should definitely be 100 Ohm and not 100kOhm. 100k would make it a noise disaster. They should also be metal film (from the expensive box, not from the standard box). This is the same for all channels so might as well stuff them.

The circuit diagram between TP3 and TP4 appears to be designed to make the whitening not work. That's why R6 & R7 should be 100k. And R2 should be metal film too.

Basically, every time we want good low frequency performance we have to use the metal film or metal foil or wirewound resistors. Everything else produces a lot of crackling noise under the influence of DC current.

I'm also attaching the voltage and current noise spectra for the AD620 from the datasheet. These should allow us to compare our measurements to a reasonable baseline.


While we're comparing things to other things, Ben Abbott just emailed me his measurement of the AD620 from back in the day. Clara's going to use this along with the specs to make sure that (a) we're not taking crazy measurements and (b) our AD620s aren't broken and in need of replacement. In this plot, we're looking at the GOLD trace, which has the AD620 set up with a gain of 10, which is how our AD620's are set up in the Guralp breakout box.

Just picking a single point to compare, it looks like at 1Hz, Ben saw ~130dBVrms/rtHz. Converting this to regular units [ 10^(#dB/20)*1Vrms = Vrms ], this is about 3*10^-7 Vrms. That means that Clara's measurements of our AD620 noise is within a factor of 2 of Ben's. Maybe the way we're connecting them up just isn't allowing us to achieve the ~50nV/rtHz that is claimed.
Attachment 1: AD620noise_BenAbbott.pdf
AD620noise_BenAbbott.pdf
  1764   Mon Jul 20 12:35:21 2009 robConfigurationLockingalignment biases funny

I found the alignment biases for the PRM and the SRM in a funny state.  It seemed like they had been "saved" in badly misaligned position, so the restore scripts on the IFO configure screen were not working.  I've manually put them into a better alignment.

  1763   Mon Jul 20 10:35:06 2009 steveUpdateVACUPS batteries replaced

 APC Smart-UPS (uninterruptible power supply) batteries RBC12 replaced at 1Y8 vacuum rack.

Their life span were 22 months.

  1762   Sun Jul 19 22:38:24 2009 robOmnistructureGeneralWeb screenshots aren't being updated

Quote:

Before heading back to the 40m to check on the computer situation, I thought I'd check the web screenshots page that Kakeru worked on, and it looks like none of the screens have been updated since June 1st.  I don't know what the story is on that one, or how to fix it, but it'd be handy if it were fixed.

 Apparently I broke this when I added op540m to the webstatus page.  It's fixed now.

  1761   Sat Jul 18 19:49:48 2009 ranaUpdatePEMGuralp Box Fail
That's terrible: R5 & R8 should definitely be 100 Ohm and not 100kOhm. 100k would make it a noise disaster. They should also be metal film (from the expensive box, not from the standard box). This is the same for all channels so might as well stuff them.

The circuit diagram between TP3 and TP4 appears to be designed to make the whitening not work. That's why R6 & R7 should be 100k. And R2 should be metal film too.

Basically, every time we want good low frequency performance we have to use the metal film or metal foil or wirewound resistors. Everything else produces a lot of crackling noise under the influence of DC current.

I'm also attaching the voltage and current noise spectra for the AD620 from the datasheet. These should allow us to compare our measurements to a reasonable baseline.
Attachment 1: Picture_1.png
Picture_1.png
Attachment 2: Picture_2.png
Picture_2.png
Attachment 3: AD620.pdf
AD620.pdf AD620.pdf AD620.pdf AD620.pdf AD620.pdf AD620.pdf AD620.pdf AD620.pdf
  1760   Fri Jul 17 18:04:54 2009 ClaraUpdatePEMGuralp Box Fail

I've been trying for most of the week to get noise measurements on the output of the Guralp box as well as scross the AD640 chip. The measurements haven't really been making sense, and, being at a loss as to what else I should try, I decided to redo the resistors on the N/S 2 and E/W 2 channels. (I had been comparing the VERT1 and VERT2 channels, as VERT1 has been restuffed and VERT2 has not.) I don't need all three of the second set of channels to do more measurements, so it seemed like a good use of time.

The first thing I noticed was that the VERT2 channel was missing two resistors (R24 and R25). I probably should have noticed this sooner, as they are right by the output points I had been measuring across, but it didn't occur to me that anyone did anything to the VERT2 channel at all. So, probably the measurements on VERT2 are no good.

VERT2_missing_resistors.png

Note the existence of 100 kOhm resistors on the top channel, and none on the bottom channel (VERT2).

 

Then, while I was soldering in some 100 Ohm resistors, I happened to notice that the resistors I was using had a different number (1001) on them than the corresponding ones on the already redone channels (1003). I checked the resistance, and the ones on the already redone channels turned out to be 100 kOhm resistors, rather than 100 Ohms. So, I double checked the circuit diagram to make sure that I had read it correctly, and there were a number of resistors that had been relabeled as 100 Ohms and several relabeled as 100 kOhms. On the board, however, they were ALL 100 kOhms. Clearly, one of them is wrong, and I suspect that it is the circuitboard, but I don't know for sure.

resistors_diagram.png

resistors_board.png

The diagram clearly shows that R6 should be a 100k resistor, while R5 and R8 should be 100 Ohm resistors, but they are all the same (100k) on the board. I suspect this may have something to do with larger-than-expected noise measurements. But, it's possible the diagram is wrong, not the board. In any case, I didn't really know what to do, since I wasn't sure which was right, so I just replaced all the resistors I was sure about and removed the 100k and 100 Ohm resistors without replacing them with anything. Incidentally, the box of 100kOhm resistors seems to be missing, so I wouldn't have been able to finish those anyway.

  1759   Thu Jul 16 14:54:05 2009 robUpdateLockingMC_F channel dead

Quote:

Quote:

It's railed.  This is what halted locking progess on Monday night, as this channel is used for the offloadMCF script, which slowly feeds back a CARM signal to the ETMs to prevent the VCO from saturating.

 

Attached is a 5 day trend, which shows that the channel went dead a few days ago.  All the channels shown are being collected from the same ICS110B (I think), but only some are dead.  It looks like they went dead around the time of the "All computers down" from Sunday.

 Attached are the channels being recorded from the ICS110B in 1Y2 (the IOO rack).  Channels 12, 13, 16, 17, 22, 24, 25 appear to have gone dead after the computer problems on Sunday.

 This has been fixed by one of the two most powerful & useful IFO debugging techniques: rebooting.  I keyed the crate in 1Y2.

  1758   Thu Jul 16 14:41:38 2009 robUpdateLockingMC_F channel dead

Quote:

It's railed.  This is what halted locking progess on Monday night, as this channel is used for the offloadMCF script, which slowly feeds back a CARM signal to the ETMs to prevent the VCO from saturating.

 

Attached is a 5 day trend, which shows that the channel went dead a few days ago.  All the channels shown are being collected from the same ICS110B (I think), but only some are dead.  It looks like they went dead around the time of the "All computers down" from Sunday.

 Attached are the channels being recorded from the ICS110B in 1Y2 (the IOO rack).  Channels 12, 13, 16, 17, 22, 24, 25 appear to have gone dead after the computer problems on Sunday.

Attachment 1: IOO_ICS_0_15.png
IOO_ICS_0_15.png
Attachment 2: IOO_ICS_15_32.png
IOO_ICS_15_32.png
  1757   Thu Jul 16 10:52:58 2009 ClaraUpdatePEMSingle Channel TRS-RNC Cable

I made and tested a female-to-female TRS(audio)-RNC cable. It only has a single channel, so it won't work for stereo speakers or anything, but I should only need one speaker for testing the microphones. The tip of the plug is the signal, the sleeve is ground, and the ring is null.

  1756   Thu Jul 16 09:49:52 2009 AlanUpdateComputersfb40m

Quote:

The fb40m just went out of order with status indicator number 8

It recovered on its own five minutes later.

 Backup script restarted, backup of trend frames and /cvs/cds is up-to-date.

 

  1755   Thu Jul 16 01:00:56 2009 AlbertoUpdateLockingPD9 aligned

Quote:

Quote:

Since lately the alignment of the input beam to the interferometer has changed, I went checking the alignment of the beam on the photodiodea. They were all fine except for pd9, that is AS DD 199. Here the DC is totally null. The beam seems to go right on the diode but the scope on the PD's DC output shows no power. This is really strange and bad.

After inspecting PD9 with the viewer and the cards, the beam looks like it is aligned to the photodiode althought there is no signal at the DC output of the photodetector. So I checked the spectrum for PD9_i and Q (see attachments) and it seems that those channels are actually seeing the beam. I'm going to check the alignemtn again and see the efefct on the spectra to make sure that the beam is really hitting the PD.

 

 I aligned PD9. Here are the spectra confirming that.

p.s.
Ants, theyre everywhere, even inside the AS table. They're taking over the lab, save yourself!
Attachment 1: 2009-07-15_PD9spectrumPDF02.pdf
2009-07-15_PD9spectrumPDF02.pdf
  1754   Wed Jul 15 18:35:11 2009 StephanieUpdateGeneralMultiply Resonant EOM Update

Using FET probes, I was able to measure a transfer function that looks a little more like what I expected. There are only two peaks, but I think this can be explained by a short between the two capacitors (and two tunable capacitors) in the LC pairs, as shown (in red) in the circuit diagram attached. The measured transfer function (black), along with the simulated transfer functions with (red) and without (blue) the short are shown in the attached plot. The measured transfer function doesn't look exactly like the simulated transfer function with the short, but I think the difference can be explained by stray impedances.

Attachment 1: BuiltCkt1_Final.png
BuiltCkt1_Final.png
Attachment 2: BuiltCkt1_TransferFunctions.png
BuiltCkt1_TransferFunctions.png
  1753   Wed Jul 15 18:22:15 2009 KojiUpdateCamerasRe: GigE Phase Camera

Quote:

Koji recommended that we use the optical setup pictured below.  Although it uses fewer optics, I can't think of a way to test the phase camera using this configuration because any modulation of the wavefront with a lens or whatever would be automatically corrected for in the PLL so I think I'll have to stick with the old configuration.

I talked with Zach. So this is just a note for the others.

The setup I suggested was totally equivalent with the setup proposed in the entry http://131.215.115.52:8080/40m/1721, except that the PLL PD sees not only 29.501MHz, but also 1kHz and 59.001MHz. These additional beating are excluded by the PD and the PLL servo. In any case the beating at 1kHz is present at the camera. So if you play with the beamsplitter alignment you will see not only the perfect Gaussian picture, but also distorted picture which is resulted by mismatching of the two wave fronts. That's the fun part!

The point is that you can get an equivalent type of the test with fewer optics and fewer efforts. Particularly, I guess the setup would not be the final goal. So, these features would be nice for you.

  1752   Wed Jul 15 17:18:24 2009 JenneDAQComputersDAQAWG gone, now back

Yet again, the DAQAWG flipped out for an unknowable reason.  In order of restart activities listed on the Wiki, I keyed the crate and nothing really happened, then I hit the physical reset button and nothing happened, and then I did the 'telnet....vmeBusReset', and a couple minutes later, it was all good again.

  1751   Wed Jul 15 14:42:31 2009 ZachUpdateCamerasGigE Phase Camera

Lately, I have been able to externally trigger the camera using a signal generator passing through the op-amp circuit that I built.  The op-amp circuit stabilizes the jitter in the sine wave from the signal generator and rectifies the wave.  I wrote the calculations into the code allowing me to find the phase and amplitude from the images I take.  I still need to develop code that will plot these arrays of phase and amplitude.

The mysterious dark band at the top of the ccd images continues to defy explanation.  However, I have found that it only appears for short exposure times even when the lens is completly covered.  During the next couple of days, I will try to write a routine to correct for this structure in the dark field.

Koji recommended that we use the optical setup pictured below.  This configuration would require fewer optics and we would have to rely on slight misalignments between the carrier and reference beams to test the effectiveness of the phase camera instead of a wavefront-deforming lens.

Attachment 1: fig1koji.pdf
fig1koji.pdf
  1750   Wed Jul 15 12:44:28 2009 Chris ZimmermanUpdateGeneralWeek 4/5 Update

I've spent most of the last week working on finishing up the UCSD calculations, comparing it to the EUCLID design, and thinking about getting started with a prototype and modelling in MATLAB.  Attached is something on EUCLID/UCSD sensors.

Attachment 1: Comparison.pdf
Comparison.pdf Comparison.pdf
  1749   Wed Jul 15 12:14:08 2009 AlbertoUpdateLockingphotodiode alignment check

Quote:

Since lately the alignment of the input beam to the interferometer has changed, I went checking the alignment of the beam on the photodiodea. They were all fine except for pd9, that is AS DD 199. Here the DC is totally null. The beam seems to go right on the diode but the scope on the PD's DC output shows no power. This is really strange and bad.

After inspecting PD9 with the viewer and the cards, the beam looks like it is aligned to the photodiode althought there is no signal at the DC output of the photodetector. So I checked the spectrum for PD9_i and Q (see attachments) and it seems that those channels are actually seeing the beam. I'm going to check the alignemtn again and see the efefct on the spectra to make sure that the beam is really hitting the PD.

 

Attachment 1: 2009-07-15_PD9spectrumPDF.pdf
2009-07-15_PD9spectrumPDF.pdf
  1748   Wed Jul 15 12:11:17 2009 StephanieUpdateGeneralMultiply Resonant EOM Update

This week I've been working on testing the first version of the prototype circuit. Initially, I tested the circuit that I built last week, which had resistors in the place of the transformer. The magnitude and phase of the transfer function, as measured by the Agilent 4395A, are shown in the attached plot (first plot, MeasuredTransferFunction_R.jpg). The transfer function doesn't look like the simulated transfer function (second plot, BuiltCkt_ExpectedResponse.png), but I think I see the three peaks at least (although they're at the wrong frequencies). I spent some time trying to recreate the actual transfer function using LTSpice, and I think it's reasonable that the unexpected response could be created by extra inductance, resistance, capacitance and interaction between components.

When the transformer arrived  yesterday, I replaced the resistors in the circuit with the transformer, and I have measured the following response (last plot, MeasuredTransferFunction.jpg). The gain is much lower than for the circuit with the resistors; however, I am still trying to track down loose connections, since the measured transfer function seems very sensitive to jiggled wires and connections.

Meanwhile, the parts for a flying-component prototype circuit have been ordered, and when they arrive, I'll build that to see if it works a little better.

Attachment 1: MeasuredTransferFunction_R.jpg
MeasuredTransferFunction_R.jpg
Attachment 2: BuiltCkt_ExpectedResponse.png
BuiltCkt_ExpectedResponse.png
Attachment 3: MeasuredTransferFunction.jpg
MeasuredTransferFunction.jpg
  1747   Wed Jul 15 11:38:31 2009 robUpdateLockingMC_F channel dead

It's railed.  This is what halted locking progess on Monday night, as this channel is used for the offloadMCF script, which slowly feeds back a CARM signal to the ETMs to prevent the VCO from saturating.

 

Attached is a 5 day trend, which shows that the channel went dead a few days ago.  All the channels shown are being collected from the same ICS110B (I think), but only some are dead.  It looks like they went dead around the time of the "All computers down" from Sunday.

Attachment 1: mcfdead.png
mcfdead.png
  1746   Wed Jul 15 08:59:30 2009 steveUpdateComputersfb40m

The fb40m just went out of order with status indicator number 8

It recovered on its own five minutes later.

  1745   Tue Jul 14 17:48:20 2009 JenneOmnistructureEnvironmentRemoval of the cold air deflection device for the MOPA chiller

Quote:

Quote:

Quote:
Around 2 PM today, I removed the blue flap which has been deflecting the cold air from the AC down into the laser chiller.
Let's watch the laser trends for a few days to see if there's any effect.


Alberto has moved us to stage 2 of this experiment: turning off the AC.

The situation at the control room computers with the AC on minus the blue flap is untenable--it's too cold and the air flow has an unpleasant eye-drying effect.


I turned the AC back on because the temperature of the room was going up so also that of the laser chiller.


I reinstalled the blue-flap technology on the AC, because the MOPA power was dropping like a rock. A light-ish rock since it wasn't going down too fast, but the alarms started going a little while ago because PMC trans was too low, because the power was getting a little low. The laser water chiller is reading 21.97C, which is higher than it normally does/did before the AC shenanigans (It usually reads 20.00C).

Attached is a look-back of 18 hours, during which you can see in the AMPMON the time that Rana removed the blue flap around 2pm yesterday and the AMPMON changes a little bit, but not drastically, the time around 11pm when the AC was turned off, and AMPMON goes down pretty fast, and about 12:30am, when Alberto turned the AC back on, and AMPMON starts to recover. I think that the AMPMON starts to go down again in the morning because it's been crazy hot here in Pasadena, so the room might be getting warmer, especially with the laser chiller-chiller not actively chilling the laser chiller (by not being pointed at the water chiller), so the water isn't getting as cold, and the HTEMP started to go up.

In the last few minutes of having put the blue flap back on the AC, the laser chiller is already reading a lower temperature, and the AMPMON is starting to recover.
Attachment 1: ACeffectonLASER2.png
ACeffectonLASER2.png
  1744   Tue Jul 14 16:31:46 2009 ClaraUpdatePEMFrequency Response of Microphone (Bonnie)

So, I actually took these measurements last week, but I didn't get around to making nice plots and things until now. I figured the time while I wait for the spectrum analyzer to do its thing was a good time.

Having been unable to locate the SR785 and also unsure how to connect it to a computer speaker (and also unable to find a free one), I downloaded a demo of a function generator onto my computer and just used that. (Same thing I used to do the swept sine that created the frequency power response plots I posted last week.) I set the program to a number of different frequencies and had the other end of the cable hooked into the oscilloscope to see a) if I could pick out the frequency and b) see how the magnitude of the microphone output varied with the frequency.

The first set of measurements I took, I didn't realize that I could increase the output power of the function generator. Because the generated sound at the default setting was relatively quiet, the oscilloscope traces were pretty chaotic, so I usually froze the trace so that I could look at it better. I ended up with a lot of weird jumps in the magnitude, but I later realized that there was a lot of beating going on at some frequencies, and the amplitude changes were probably much more drastic for the -20 dB sounds than the 6 dB sounds, since it was closer in amplitude to the surrounding noises. So, I've included that data set in my plots for the sake of completeness, but I'm pretty sure that it is useless.

Once I realized I could increase the power output for the signal generator, I took a set of data with and without the voltage divider at 6 dB. There was a cluster of frequencies that showed significant beating around 1700-3000 Hz in the data WITH the voltage divider, but I did not see any clear beating in the data WITHOUT. In the plots, I simply plotted up the highest and lowest amplitudes I measured for the frequencies with significant beating, since it was obviously hard to tell what the amplitude would have been without any background noise. In the w/o volt. div. set, although I didn't see any obvious beat patterns, the measured amplitudes did jump slightly at the frequencies that showed beats with the voltage divider. So, perhaps I was just not seeing them, but they influenced my amplitude measurements? I'm not sure if it would be possible for the voltage divider itself to cause beat frequencies.

 (Note: the amplitudes measured were from zero to peak, as the oscilloscope I was using wouldn't show a big enough vertical range to easily measure the peak-to-peak voltage difference.)

I've attached two plots of my measurements. One has a regular x-scale and includes all the measurements. The second has a logarithmic x-scale and omits the 20 Hz points. I had some troubles being able to pick out the 20 Hz signal on the oscilloscope... I don't know if my computer speakers just don't work well at that frequency or what, but either way, those points seemed highly suspect, and omitting them from the log plot allowed me to spread things out more.

One thing I'm not sure about is the 3000 Hz point. It was one of the ones with a beat frequency (~130 Hz), and the amplitudes were pretty low. The corresponding point from the non-voltage-divider data set is also low. So, I'm not sure what's happening there.

The one thing that I do think is quite clear is that the 1000 Hz drop-off in power when the microphone is connected to the ADC has nothing to do with the voltage divider. Beat issues aside, the shapes are very similar (pay no attention to the absolute scale... obviously, the voltage responses with and without the voltage divider were very different, and I just scaled them to fit in the same plot).

Update: Jenne pointed out that I was not absolutely clear about the voltage scale in my plots. The GREEN and BLUE points are on a mV scale, and the RED points are on a 10mV scale. I should probably redo the plots in Matlab in eventuality, since Excel is hard to use if you want to do anything that is not extremely basic with your plots, but this was my solution for the time being. So, the fact that the RED points, which are the data taken WITHOUT the voltage divider, are lower than the GREEN ones does not in any way indicate that I measured lower voltages when the voltage divider was not used.

Also, a to do list:

- Many of the beat frequencies I picked out were veeeeery slow, indicating that something is going at a frequency that is very close to the arbitrary frequencies I chose to sample, which is a little strange. That, combined with the fact that I saw clear beats with the voltage divider but not without leads me to believe that it may be worth investigating the frequency response of the voltage divider itself.

- Redo the measurements near the anomalous 3000 Hz point with a higher density of sampled frequencies to try to see what the heck is going on there.

Attachment 1: Bonnie_fres_regplot.pdf
Bonnie_fres_regplot.pdf
Attachment 2: Bonnie_fres_logplot.pdf
Bonnie_fres_logplot.pdf
  1743   Tue Jul 14 14:54:19 2009 steveConfigurationComputersfb40m2 in 1Y6

Alex and Steve,

SunFire x4600 ( not  MEGATRON 2 , it is fb40m2 ) and JetStor ( 16 x 1 TB drives ) were installed on side rails at the bottom of 1Y6

We cleaned up the fibres and cabling in 1Y7 also

  1742   Tue Jul 14 00:57:11 2009 AlbertoUpdateLockingphotodiode alignment check

Since lately the alignment of the input beam to the interferometer has changed, I went checking the alignment of the beam on the photodiodea. They were all fine except for pd9, that is AS DD 199. Here the DC is totally null. The beam seems to go right on the diode but the scope on the PD's DC output shows no power. This is really strange and bad.

  1741   Tue Jul 14 00:32:46 2009 rob, albertoOmnistructureEnvironmentRemoval of the cold air deflection device for the MOPA chiller

Quote:

Quote:
Around 2 PM today, I removed the blue flap which has been deflecting the cold air from the AC down into the laser chiller.
Let's watch the laser trends for a few days to see if there's any effect.


Alberto has moved us to stage 2 of this experiment: turning off the AC.

The situation at the control room computers with the AC on minus the blue flap is untenable--it's too cold and the air flow has an unpleasant eye-drying effect.


I turned the AC back on because the temperature of the room was going up so also that of the laser chiller.
  1740   Mon Jul 13 23:03:14 2009 rob, albertoOmnistructureEnvironmentRemoval of the cold air deflection device for the MOPA chiller

Quote:
Around 2 PM today, I removed the blue flap which has been deflecting the cold air from the AC down into the laser chiller.
Let's watch the laser trends for a few days to see if there's any effect.


Alberto has moved us to stage 2 of this experiment: turning off the AC.

The situation at the control room computers with the AC on minus the blue flap is untenable--it's too cold and the air flow has an unpleasant eye-drying effect.
  1739   Mon Jul 13 16:59:10 2009 ZachUpdate GigE Phase Camera

Today, I moved the router from on top of the PSL into the control room in order to perform dark field tests on the GC650 (which I also moved).  The GC750 along with the lens that was on it and the mount it was on has been lent to Ricardo's lab for the time being.  I successfully triggered the GC650 externally and I also characterized the average electronic noise.  For exposure times less than 1 microsecond, the average noise contribution appears to be a constant 15 on a 12-bit scale.

  1738   Mon Jul 13 15:48:05 2009 ranaOmnistructureEnvironmentRemoval of the cold air deflection device for the MOPA chiller
Around 2 PM today, I removed the blue flap which has been deflecting the cold air from the AC down into the laser chiller.
Let's watch the laser trends for a few days to see if there's any effect.
  1737   Mon Jul 13 15:14:57 2009 AlbertoUpdateComputersDAQAWG

Today Alex came over, performed his magic rituals on the DAQAWG computer and fixed it. Now it's up and running again.

I asked him what he did, but he's not sure of what fixed it. He couldn't remember exactly but he said that he poked around, did something somewhere somehow, maybe he tinkered with tpman and eventually the computer went up again.

Now everything is fine.

  1736   Mon Jul 13 00:53:50 2009 AlbertoDAQComputersAll computers down

Quote:

Quote:

I popped by the 40m, and was dismayed to find that all of the front end computers are red (only framebuilder, DAQcontroler, PEMdcu, and c1susvmw1 are green....all the rest are RED).

 

I keyed the crates, and did the telnet.....startup.cmd business on them, and on c1asc I also pushed the little reset button on the physical computer and tried the telnet....startup.cmd stuff again.  Utter failure. 

 

I have to pick someone up from the airport, but I'll be back in an hour or two to see what more I can do.

 I think the problem was caused by a failure of the RFM network: the RFM MEDM screen showed frozen values even when I was power recycling any of the FE computers. So I tried the following things:

- resetting the RFM switch
- power cycling the FE computers
- rebooting the framebuilder
 
but none of them worked.  The FEs didn't come back. Then I reset C1DCU1 and power cycled C1DAQCTRL.
 
After that, I could restart the FEs by power recycling them again. They all came up again except for C1DAQADW. Neither the remote reboot or the power cycling could bring it up.
 
After every attempt of restarting it its lights on the DAQ MEDM  screen turned green only for a fraction of a second and then became red again.
 
So far every attempt to reanimate it failed.

 

After Alberto's bootfest which was more successful than mine, I tried powercycling the AWG crate one more time.  No success.  Just as Alberto had gotten, I got the DAQ screen's AWG lights to flash green, then go back to red.  At Alberto's suggestion, I also gave the physical reset button another try.  Another round of flash-green-back-red ensued.

When I was in a few hours ago while everything was hosed, all the other computer's 'lights' on the DAQ screen were solid red, but the two AWG lights were flashing between green and red, even though I was power cycling the other computers, not touching the AWG at the time.  Those are the lights which are now solid red, except for a quick flash of green right after a reboot.

I poked around in the history of the curren and old elogs, and haven't found anything referring to this crazy blinking between good and bad-ness for the AWG computers.  I don't know if this happens when the tpman goes funky (which is referred to a lot in the annals of the elog in the same entries as the AWG needing rebooting) and no one mentions it, or if this is a new problem.  Alberto and I have decided to get Alex/someone involved in this, because we've exhausted our ideas. 

  1735   Mon Jul 13 00:34:37 2009 AlbertoDAQComputersAll computers down

Quote:

I popped by the 40m, and was dismayed to find that all of the front end computers are red (only framebuilder, DAQcontroler, PEMdcu, and c1susvmw1 are green....all the rest are RED).

 

I keyed the crates, and did the telnet.....startup.cmd business on them, and on c1asc I also pushed the little reset button on the physical computer and tried the telnet....startup.cmd stuff again.  Utter failure. 

 

I have to pick someone up from the airport, but I'll be back in an hour or two to see what more I can do.

 I think the problem was caused by a failure of the RFM network: the RFM MEDM screen showed frozen values even when I was power recycling any of the FE computers. So I tried the following things:

- resetting the RFM switch
- power cycling the FE computers
- rebooting the framebuilder
 
but none of them worked.  The FEs didn't come back. Then I reset C1DCU1 and power cycled C1DAQCTRL.
 
After that, I could restart the FEs by power recycling them again. They all came up again except for C1DAQADW. Neither the remote reboot or the power cycling could bring it up.
 
After every attempt of restarting it its lights on the DAQ MEDM  screen turned green only for a fraction of a second and then became red again.
 
So far every attempt to reanimate it failed.
  1734   Sun Jul 12 23:14:56 2009 JenneOmnistructureGeneralWeb screenshots aren't being updated

Before heading back to the 40m to check on the computer situation, I thought I'd check the web screenshots page that Kakeru worked on, and it looks like none of the screens have been updated since June 1st.  I don't know what the story is on that one, or how to fix it, but it'd be handy if it were fixed.

  1733   Sun Jul 12 20:06:44 2009 JenneDAQComputersAll computers down

I popped by the 40m, and was dismayed to find that all of the front end computers are red (only framebuilder, DAQcontroler, PEMdcu, and c1susvmw1 are green....all the rest are RED).

 

I keyed the crates, and did the telnet.....startup.cmd business on them, and on c1asc I also pushed the little reset button on the physical computer and tried the telnet....startup.cmd stuff again.  Utter failure. 

 

I have to pick someone up from the airport, but I'll be back in an hour or two to see what more I can do.

  1732   Sun Jul 12 20:05:06 2009 ranaOmnistructureEnvironmentChanged office temp
This is a 7-day minute trend. There's no obvious effect in any of the channels looking back 2 days.

Seems like the laser chiller fix has made the laser much more immune to the office area temperature.
Attachment 1: Picture_3.png
Picture_3.png
ELOG V3.1.3-