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ID Date Author Type Category Subjectup
  15098   Mon Dec 16 18:19:42 2019 shrutiUpdatePSLPMC cavity ringdown measurement : beat-note disruption

I have removed the PD55 + ND filter attached to it (see Attachment) and placed it next to the oscilloscope, after disconnecting its output and power supply. The post is still in place.

I did see the beat after that.

Quote:

{Yehonathan, Rana, Jon}

To check whether we laser is being shut fast enough for the ringdown measurement we put a PD55 in the path that leads to the beat note setup. The beam is picked off from the back steering mirror after AOM and before the PMC.

@Shruti the PD is now blocking the beam to your setup.

 

Attachment 1: IMG_0040.jpg
IMG_0040.jpg
  12939   Tue Apr 11 00:38:37 2017 gautamUpdatePSLPMC demod moved off servo board

As discussed at the Wednesday meeting last week, I tried moving the demodulation of the PMC error signal off the PMC servo board, by using some minicircuits components. This is just a quick summary elog, more details to follow tomorrow.

  • I used the Mini Circuits ZAD-6+. This is a level 7 mixer, and the LO board puts out ~16dBm, so I replaced the existing 3dB attenuator between the LO board and the input to the PMC servo board with a 9dB attenuator.
  • On the RF side, I retained the 35.5 MHz bandpass filter on the PD input.
  • On the IF output, I used an in-line 50ohm terminator in series with a minicircuits BLP1.9+ low pass filter
  • The mixer output was routed to the FP1 test input of the servo board
  • After some twiddling with the demod phase MEDM screen, I was able to lock the PMC. I've not done a thorough characterization of the loop with the current configuration, this will be done tomorrow. But the PMC and IMC have been stably locked for the last couple of hours...

During the course of this work, I noticed that there was a 35.5MHz line (at ~-55dBm) in the 4-pin LEMO DAQ outputs even when all other inputs to the servo board were terminated. So it seems like this pickup is not coming from the RFPD or demod path. The LO board has a shield enclosure similar to what we have on the LSC demod boards, but perhaps this shield does not enclose the full RF path, and there is some residual pickup between the two cards in close proximity in the Eurocrate?

On the bright side, with this demod setup, the higher harmonic peaks seem to be significantly suppressed.

In particular, the 3x35.5 MHz peak which was very prominent when I looked at these spectra with the nominal demod setup, seems to be much suppressed. 

I'm leaving the PMC servo in this configuration (off servo board demodulation using minicircuits parts) overnight.

Attachment 1: PMC_Ctrl_spec.pdf
PMC_Ctrl_spec.pdf
  12940   Wed Apr 12 00:36:53 2017 gautamUpdatePSLPMC demod moved off servo board

Here is a more detailed comparison of the spectra of the signals at the front panel DAQ LEMO output, measured with the Agilent analyzer. I've left the scale linear, it looks like when the demodulation is done on the servo board, the 1x, 3x and 5x harmonics of the 35.5MHz modulation are clearly visible. I also plut in a plot of the spectra when both the PD and LO inputs to the servo board are terminated (and so the PMC is unlocked), but with the HV In and OUT of the servo board still connected. In this case, the higher harmonics vanish, but a 35.5MHz peak of ~-50dBm remains. Since this is present with no input to the servo board, this must be direct pickup from the nearby LO board? 

In any case, it looks like many of the harmonics that are present with the nominal demod setup either vanish or are much more suppressed when the error signal demodulation is done off the servo board yes.


Further down the signal chain, I had noticed sometime last week that the ADC signals for the PMC DAQ channels I set up seemed to saturate around 4000 counts. Rana mentioned that the ADC interface box with LEMO connectors on the front is powered with +/-5V. Valera and co. had simply increased the suppy voltage sometime ago to get around this problem, so I did something similar, and increased the supply voltage to +/- 15V. I then confirmed that the ADC doesn't get saturated by driving the input with a +/-5V signal. So now the amplified AD620 signals from the PMC servo board are better matched to the ADC range. 

Here is an uncalibrated spectrum (taken with IMC locked), compared to the current ADC noise and signal levels before the AD620s were given gain.

I now need to think a little about what exactly the control scheme would be if the PMC is used as a reference for the IMC over some frequency range...

 

Attachment 1: PMC_digitalSpec.pdf
PMC_digitalSpec.pdf
Attachment 2: PMC_DAQ_spectra.pdf
PMC_DAQ_spectra.pdf
  15143   Wed Jan 22 20:12:36 2020 gautamUpdatePSLPMC demodulator electrical characterization

Summary:

The mixer + LPF combo used to demodulate the PMC PDH error signal seems to work as advertised.

Details:

Measurement setup --- Attachment #1. The IF signal was monitored using the scope in High-Z mode.

Results --- Attachment #2.

So the next step is to characterize the RF transimpedance of the PMC RFPD.

Attachment 1: demodChar.pdf
demodChar.pdf
Attachment 2: mixerChar.pdf
mixerChar.pdf
  7810   Tue Dec 11 11:40:07 2012 Manasa, AyakaUpdatePSLPMC drift

[Manasa, Ayaka]

I found that MC got unstable this morning. This is caused by the drift of PMC. The transmission of PMC was going down and eventually unlocked PMC.

PMCdrift121211.pdf

We adjusted 'Slow Actuator Adjust' in FSS and now the PMC is locked with transmission of ~ 0.735.
Also we aligned the MC to be locked. Now it is locked with transmission of ~ 0.5 with WFS and MCL on.

  1000   Fri Sep 26 18:35:17 2008 JenneUpdatePSLPMC filter is out for tuning
The PMC's new Pomona Box filter is out for tuning. I'd like to get the notch right on the 18.3kHz, rather than being off in 21.7kHz land.
  8263   Fri Mar 8 21:00:05 2013 ManasaUpdatePSLPMC fixed

Quote:

  Mystery

1. Filter module (FM1) on PRCL and MICH show significant delay while enabling and disabling.

2. I tried to fix PMC alignment (PMC trans was 0.76). I was not able to get PMC trans more than 0.79.
PMC has been this way since yesterday.

3. MICH is still bright when locked (ASDC_OUT reads 0.08 for dark and 2.0 for bright). We suspect it is because of the AS55_I error offset that persists even after running LSCoffsets script.

4. PRMI shows some dither at 3Hz when locked.

 [Koji, Manasa]

PMC is fixed with 0.84 in transmission. It was misaligned in pitch (fixing this increased PMC_trans to 0.822 from 0.773) and Koji also touched the wave plate and polarizer (changed PMC_trans to 0.845).

  4870   Thu Jun 23 22:39:34 2011 JenneUpdatePSLPMC found unlocked

I found the PMC unlocked.  Koji noticed that the FSS Slow Actuator Adjust was railed at the positive end of the slider.  I set it close to zero, and relocked the PMC.  The FSS slow loop servo is doing its thing, and the PMC and MC are now locked. 

  5705   Wed Oct 19 18:16:53 2011 JenneUpdatePSLPMC found unlocked

I just relocked the PMC.  I don't know why it was unlocked.

  5707   Wed Oct 19 19:43:16 2011 JenneUpdatePSLPMC found unlocked

Quote:

I just relocked the PMC.  I don't know why it was unlocked.

 Again....

  7811   Tue Dec 11 19:51:36 2012 KojiUpdatePSLPMC gain was too low / EPICS alerting value for PMC updated

[Ayaka, Koji]

Ayaka pointed out that the PMC has too low unity gain frequency. We checked the history of "C1:PSL-PMC_GAIN"
and found that the gain was minimum from the Friday night. It was returned to nominal gain of 10.

The PMC screen had the gain status indicator always red. This was because C1:PSL-STAT_PMC_NOM_GAIN was 2 instead of 10.
This was fixed by the following command.

ezcawrite C1:PSL-STAT_PMC_NOM_GAIN 10

This will be recorded by the snapshot in an hour.

Another annoying false alerm on the PMC screen was the PMC transmission monitor.
In order to fix this, the following commands were executed.

ezcawrite C1:PSL-PMC_PMCTRANSPD.LOLO 0.75
ezcawrite C1:PSL-PMC_PMCTRANSPD.LOW 0.8
ezcawrite C1:PSL-PMC_PMCTRANSPD.HIGH 0.9
ezcawrite C1:PSL-PMC_PMCTRANSPD.HIHI 0.95

Also the corresponding EPICS database (/cvs/cds/caltech/target/c1psl/psl.db) has been updated accordingly.

  15270   Thu Mar 12 11:10:49 2020 YehonathanUpdateGeneralPMC got unlcoked

Came this morning to find the PMC was unlocked since 6AM. Laser is still on, but PMC REFL PD DC shows dead white constant 0V on PMC screen. All the controls on the PMC screen show constant 0V actually except for the PMC_ERR_OUTPUT which is a fast channel.

 

Is PSL Acromag already failing?

 

I restarted the IOC but it didn't help.

I am now rebooting c1psl... That seemed to help. PMC screen seem to be working again. I am able to lock the PMC now.

IMC was locking easily once some switches on the MC servo screen were put to normal states.

TTs were grossly misaligned. Onces they where aligned, arm cavities were locking easily. Dither align for the X arm is very slow though...

  15271   Thu Mar 12 12:44:34 2020 gautamUpdateGeneralPMC got unlcoked

Of course the reboot wiped any logs we could have used for clues as to what happened. Next time it'll be good to preserve this info. I suspect the local subnet went down.

P.S. for some reason the system logs are priveleged now - I ran sudo sysctl kernel.dmesg_restrict=0 on c1psl to make it readable by any user. This change won't persist on reboot.

Quote:

I restarted the IOC but it didn't help.

I am now rebooting c1psl... That seemed to help. PMC screen seem to be working again. I am able to lock the PMC now.

  1502   Mon Apr 20 19:51:51 2009 JenneConfigurationPSLPMC has new Level 13 Mixer installed

The new Level 13 mixer on the PMC servo board is installed (minicircuits SRA-3MH).   Since the RF output of the LO board was ~16dBm, I put a 3dB attenuator between the LO board and the LO input on the servo board.  Since the previous cable was *just* the right length, this required adding a tiny bit of cable.  I found a very short cable, which worked out nicely, and didin't leave bunches of extra cable between the two boards.  One of these days if I have time (i.e. if it is necessary), I'll make a new cable for this purpose, so that we don't have 2 cables daisy-chained. 

A note on the Mixer-replacement:  The mixer on the PMC servo board is soldered in a set of 8 through-holes, not stuck in a socket.  So I had to desolder the old Level 23 Mixer (minicircuits RAY-3) which was a total pain.  Unfortunately, in this process, I lifted one of the pads off the back side of the board.  Once the old mixer was removed, it became clear that the pin for the pad I had lifted was shorted via a trace on the front side of the board to the pin directly across from it.  So when installing the new mixer, I did my best to get some solder into the through-hole for the lifted-pad-pin, and then tied it using a jumper wire to the pin that it's shorted to on the front of the board.  You can't see the trace that shorts the two pins because it's underneath the mixer, when the mixer is installed.  (Sidenote: after talking with Rana, this should be okie-dokie, especially if these are ground pins).

The PMC and MC locked nice and happily after I replaced the board and turned all the HV supplies back on, so I call this a success!

I also measured the OLG of the PMC servo after today's adventures in mixer-land.  I get a UGF of 1.4kHz, with 66 degrees of phase margin.  The method for this is in elog 924.

I checked the phase slider setting of the PMC phase screen by putting 30kHz at 100mV into the Ext DC input of the servo board, and looking at the 30kHz peak output of the Mixer Out.  I fiddled with the phase slider, and chose the value for which the 30kHz peak was maximized.  The phase slider is now set to 5.0V. 

Attachment 1: PMColg20Apr2009.png
PMColg20Apr2009.png
  612   Tue Jul 1 12:08:38 2008 John, JoeConfigurationPSLPMC input PD
Joe and I switched cables so that the PMCR screen actually shows reflection not transmission.

The trans camera had a BNC connected to "video out" labelled PMC input PD. The video signal
going to the monitors does not come from "video out", it comes out the "DC in/sync" cable.
As far as we can see this diode doesn't exist. Where should the PMC input PD BNC cable be
connected?
  5724   Fri Oct 21 15:49:35 2011 SureshUpdateIOOPMC input alignment improved

The image on the PMCR camera was quite assymetric and PMC output was at 80% .... upon improving the alignment I managed to push it up to 87%

 

  16917   Wed Jun 15 15:03:41 2022 KojiUpdatePSLPMC input beam aligned

The commissioners complained about the PMC alignment. The PMC input beam was aligned. It made the transmission improved from 0.72 to 0.74.

FYI: Which steering mirrors do we use for the PMC beam alignment?
The mounts are indicated with the red arrows in Attachment 2.
You have to move these two in common and differential for each pitch and yaw.
The first steering (the right one in the picture) has the beam going through the immediate back of the mount.
So touching the yaw knob of this mount needs some care so that you don't block the PMC refl beam.

Attachment 1: Screenshot_2022-06-15_15-03-16.png
Screenshot_2022-06-15_15-03-16.png
Attachment 2: PXL_20220615_212304650.jpg
PXL_20220615_212304650.jpg
  16922   Thu Jun 16 15:29:03 2022 yutaUpdatePSLPMC input beam aligned again, IMC

[Paco, Tomislav, Yuta]

Somehow, when we were trying to measure WFS open loop transfer functions, PMC unlocked many times for the past two hours and PMC transmission got low.
PMC iput beam was aligned again, and IMC WFS DC offsets and RF offsets were adjusted.
PMC transmission is now C1:PSL-PMC_PMCTRANSPD~0.75, and IMC transmission is C1:IOO-MC_TRANS_SUM~1.4e4.
Actually, IMC transmission once reached 1.5e4 at 06-16-2022 20:01 UTC with PMC transmission of 0.75 (see Attached). There might be a better alignment.

Attachment 1: Screenshot_2022-06-16_15-27-30.png
Screenshot_2022-06-16_15-27-30.png
  9707   Mon Mar 10 12:49:27 2014 JenneUpdateIOOPMC input pointing misaligned

I don't know why, but as you can see in Steve's plot from earlier this morning, the PMC transmission has been going down significantly all weekend.  The PMC refl camera was very bright.  I tweaked up the alignment (mostly pitch), and now we're back to normal. 

The IMC was having trouble staying locked all morning, and I'm hoping that this PMC adjustment will help - the MC already looks better, although it's only been a few minutes.

  527   Mon Jun 9 17:57:59 2008 YoichiConfigurationPSLPMC input power backed to the original
I rotated back the HWP before the PBS to restore the input laser power to the PMC.
Now the reading of PSL-PMC_PMCTRANSPD is 2.7.
  15133   Mon Jan 20 12:16:50 2020 gautamUpdatePSLPMC input reverted to AOM zeroth order beam

Summary:

  1. The input beam to the PMC cavity was changed back to the zeroth order beam from the AOM. 
  2. The PMC was locked and nominal transmission levels were recovered.
  3. The AOM driver voltage was set to 0V DC. 
  4. A razor beam dump was placed to catch the first (and higher order) beams from the AOM (see Attachment #1), but allow the zeroth order beam to reach the PMC cavity.
  5. Some dangling cabling was cleared from the PSL enclosure.

Details

  • HEPA turned to 100% while work was going on in the PSL enclosure.
  • Input power to the PMC cut from ~1.3 W to ~20 mW using the first available HWP downstream of the laser head, before any realignment work was done.
  • Next, the beam dump blocking the undeflected zeroth order beam was removed.
  • Triangle wave was applied to the PZT servo board "EXT DC" input to sweep the cavity length to make the alignment easier.
  • After some patient alignment, I could see a weak transmitted beam locked to some high order mode, at which point I increased the input power to 200mW, and did the fine alignment by looking at the mode shape of the transmitted beam.
  • Once I could lock to a TEM00 mode, I bumped the power back up to the nominal 1.3W, I fine tuned the alignment further by minimizing PMC REFL's DC level. 
  • Dialled the power back down (using HWP) for installation of the beam block to catch the AOM's first (and higher order) beams.
  • Checked that the reflected beam from the PMC cavity is well centered on the PMC REFL PDH photodiode. The ghost from the AR coating of the high-T beamsplitter is blocked by the iris installed by yehonathan on Friday. 
  • The beam was a little low on the PMC REFL CCD camera - I raised the camera by ~1cm.
  • With the beam axis well matched to the PMC, I measured 1.33 mW going into the cavity, and 1.1 W transmitted, so T_{\mathrm{PMC}} \approx 83 \, \%. Whatever loss numbers we extract should be consistent with this fact.
  • HEPA turned back down to 30% shortly after noon.

Note that for all the alignment work, only the two steering mirrors immediately upstream of the PMC cavity were touched.

Attachment 1: IMG_8362.JPG
IMG_8362.JPG
  7483   Thu Oct 4 22:16:40 2012 DenUpdatePSLPMC is locked

PZT monitor is not lying to us, I've measured it with a voltmeter. But PMC SERVO is still interesting. If I break the loop after PMCERR signal monitor (C1:PSL-PMC_BLANK=0), I can change PZT voltage from 0V (C1:PSL-PMC_RAMP = -7.3) to 132V (C1:PSL-PMC_RAMP=-10.0). If I break the loop by enabling TEST1, PZT voltage goes up to 294 V, though voltage on the TEST1 and MIXER MON is 0.

  15091   Tue Dec 10 15:17:17 2019 YehonathanUpdatePSLPMC is locked

{Jon, Yehonathan}

We burt-restored the PSL and the PMC locked immediately.

The PMC is now locked on the AOM first order mode.

  15092   Tue Dec 10 18:27:22 2019 YehonathanUpdatePSLPMC is locked

{Yehonathan, Jon}

We are able to lock the PMC on the TEM00 mode of the deflected beam.

However when we turn off the driving voltage to the AOM and back on the lock is not restored. It get stuck on some higher order mode.

There are plethora of modes present when the PZT is scanned, which makes us believe the cavity is misaligned.

 

To lock again on the TEM00 mode again we disconnect the loop (FP Test point 1), find a TEM00 mode using the DC output adjust and close the loop again.

 

  15094   Wed Dec 11 15:29:17 2019 YehonathanUpdatePSLPMC is locked

Make sure to measure the power drop of the beam downstream of the AOM but before the PMC. Need to plot both together to make sure the chop time is much shorter than the 1/e time.

  7895   Mon Jan 14 09:08:37 2013 SteveUpdatePSLPMC is only ok short term

 

 The PMC PZT voltage slider seemed sticky.  First it would not do anything, than after moving slider back an forth a few times, it had a range of 60V and later it had full range and it locked

Attachment 1: pmc8d.png
pmc8d.png
  7047   Mon Jul 30 09:00:18 2012 steveUpdatePSLPMC is still not fixed

The PMC was locking right the way, but it's transmission would not go up.  Finally I get it back up by moving the "sticky" DC Gain slider up and down a few times.

Attachment 1: pmcA.png
pmcA.png
Attachment 2: pmcB.png
pmcB.png
  7048   Mon Jul 30 10:05:29 2012 JenneUpdatePSLPMC is still not fixed

Quote:

The PMC was locking right the way, but it's transmission would not go up.  Finally I get it back up by moving the "sticky" DC Gain slider up and down a few times.

 The FSS was -2.9, and the PMC won't lock happily unless you bring this back to 0.  The symptom that this is happening is that the PMC reflection camera is totally saturated, but the PMC still looks like it's locked on 00.

  10316   Fri Aug 1 01:29:55 2014 KojiUpdateIOOPMC issue

- PMC suddenly refused to lock.

- Investigated what's wrong

- Finally, I touched RF Output Adjust (C1:PSL-PMC_RFADJ). Then it started locking.

- C1:PSL-PMC_RFADJ was set to 2.0 by rana when we looked at the PMC LO issue.
  Now PMC does not lock with this value. I set it to 6.0 so that the lock is robust.

- Right before I lost PMC locking, I had some difficulty in locking IMC. Of course,  the robustness of the PMC is related to the robustness of the IMC.
  We definitely need to investigate this. (RF powers, open loop TF, etc)

  3580   Fri Sep 17 01:36:14 2010 valeraUpdate PMC line width

The attached plots show the PMC cavity line width measurement with 1 mW and 160 mW into the PMC. The two curves on each plot are the PMC transmitted power and the ramp of the fast input of the NPRO. The two measurements are consistent within errors - a few %. The PMC line width  3.5 ms (FWHM) x 4 V / 20 ms (slope of the ramp) x 1.1 MHz / V (NPRO fast actuator calibration from Innolight spec sheet) = 0.77 MHz.

Here is the output of the calculation using Malik Rakhmanov code:

 

modematching =  8.4121e-01

transmission1 =   2.4341e-03

transmission2 =   2.4341e-03

transmission3 =   5.1280e-05

averageLosses =  6.1963e-04

visibility =  7.7439e-01

Here are the inputs for the calculation in the param.m:

 

fw = 0.77e6;                % width of resonance (FWHM) in Hz

Plas = 0.164;                % power into the PMC in W

 

% the following number refer to the in-lock cavity state

 

Pref = 0.037;                % reflected power in W

Ptr = 0.0712;                 % transmitted power in W

Pleak = 0.0015;              % power leaking from back of PMC in W

 

 

Attachment 1: TEK00009.PNG
TEK00009.PNG
Attachment 2: TEK00010.PNG
TEK00010.PNG
  10146   Mon Jul 7 21:36:33 2014 Jenne, ranaUpdatePSLPMC local oscillator is going wonky

The PMC local oscillator is going a little weird dyingWe need to check out why the level is fluctuating so much.

Here's a 6 month plot, where you can see that the lower level keeps getting lower (y-axis is dBm):

PMC_LO_failing.pdf

This LHO entry from 2008 shows where we first discovered this effect. As Rick Savage and Paul Schwinberg later found out, the ERA-5SM+ amplifier slowly degrades over several years and was replaced for both of the eLIGO interferometers. We have spares in the Blue box and can replace this sometime during the day.

Our PMC LO is made by this obsolete crystal oscillator circuit: D000419. There are many versions of this floating around, but they all have the ERA-5 issue.

  10148   Mon Jul 7 22:18:26 2014 KojiUpdatePSLPMC local oscillator is going wonky

It seems that there is no better chip in MiniCircuits line-up with the same form factor.
ERA-5 is the most powerful one in the ERA (or MAR) series.

If the output is ~0dBm we have MAR-6SM in stock. But I suspect that ERA-5 was driven at the power level close to its saturation (~18dBm).

If we allow different form factors, we have GVA-** or GALI-** in the market and also in the blue tower, in order to gain more performance margin.
If it is difficult to apply them, I would rather use another ERA-5 with enhanced heat radiation.

I'm sure that Downs has EAR-5 replacement.

  10153   Tue Jul 8 15:28:32 2014 KojiUpdatePSLPMC local oscillator is going wonky

Koushik and Koji try to fix the PMC oscillator issue. So we remove the module from the rack.
This means we don't have the PMC transmission during the work.

  10159   Wed Jul 9 00:47:22 2014 KojiUpdatePSLPMC local oscillator is going wonky

Koushik replaced an ERA-5 in the PC path. We put the module back to the rack and found no change.
The epics LO level monitor monitor is still fluctuating from 6~11dBm. We need more thorough investigation
by tracing the signals everywhere on the board.

Despite the poor situation of the modulation, PMC was locking (~9PM). Rana suspect that the PMC demodulation
phase was not correctly adjusted long time. 

Koushik has the measured power levels and the photos of the board. I'll ask him to report on them.

  10160   Wed Jul 9 00:59:09 2014 ranaUpdatePSLPMC local oscillator is going wonky

Quote:

Koushik and Koji try to fix the PMC oscillator issue. So we remove the module from the rack.
This means we don't have the PMC transmission during the work.

 After the ERA-5 was replaced (see Koushik elog) we relocked the PMC.

The new LO level going into the PMC servo card is +11.5 dBm. The LO mon on the PMC card reads 9 dBm and seems so flat I now suspect the monitor circuit.

I also measured the RF drive to the EOM as a function of C1:PSL-PMC_RFADJ on the Phase Shifter screen.

The phase shifter slider gives ~75 deg/V in phase shift of the RF out to the EOM. I tried to optimize the loop gain quickly using the fluctuations in the reflected power. The loop oscillates at high frequency with the slider at 21 dB and also at 9 dB. So I set the gain at +14 dB. Needs to be optimized correctly in the daytime.

 

Attachment 1: PMC_RFslider.pdf
PMC_RFslider.pdf
  10162   Wed Jul 9 11:41:12 2014 KoushikUpdatePSLPMC local oscillator is going wonky

Quote:

Koushik replaced an ERA-5 in the PC path. We put the module back to the rack and found no change.
The epics LO level monitor monitor is still fluctuating from 6~11dBm. We need more thorough investigation
by tracing the signals everywhere on the board.

Despite the poor situation of the modulation, PMC was locking (~9PM). Rana suspect that the PMC demodulation
phase was not correctly adjusted long time. 

Koushik has the measured power levels and the photos of the board. I'll ask him to report on them.

 Updates from Koushik:

The power levels measured (before and after relacement of ERA-5) are as follows:

LO to Servo : Vout = 2.3 Vpp / Pout = 11.21 dBm at f = 35.5 MHz

RF to PC   :   Vout = 354 mVpp / Pout = -5.1 dBm at f= 35.5 MHz

The measurements were done using an oscilloscope with 50 ohms load impedance. Unfortunately the photos are not available from the camera.

  5768   Mon Oct 31 09:42:12 2011 steveUpdateIOOPMC locked

The PMC HV drops off more offen lately.

Attachment 1: pmcHV.png
pmcHV.png
  5826   Mon Nov 7 08:08:24 2011 steveUpdateIOOPMC locked

The PMC acted like it was sleeping. The HV slider was dead. The MC locked instantly as the PMC had transmission.

Attachment 1: pmcHV.png
pmcHV.png
  6652   Mon May 21 07:45:39 2012 steveUpdateIOOPMC locked

I locked the PMC and the MC followed instantly.

Attachment 1: pmclocked.png
pmclocked.png
  6665   Wed May 23 10:40:21 2012 steveUpdateIOOPMC locked

Quote:

I locked the PMC and the MC followed instantly.

 

Attachment 1: pmc.png
pmc.png
  6672   Thu May 24 10:10:04 2012 steveUpdateIOOPMC locked

 The PMC  behavior is not changed.

 

Attachment 1: pmc4d.png
pmc4d.png
  6791   Mon Jun 11 09:37:16 2012 steveUpdateIOOPMC locked

Quote:

Quote:

IOO Angle & IOO Position QPDs centered.

 PMC trend of 400 and 1200 days

The Innolight 2W based PSL- IOO was implemented in the ~ summer of 2010

 The PMC was locked and the MC followed intantly

Attachment 1: PMClocked.png
PMClocked.png
  8421   Mon Apr 8 08:05:41 2013 SteveUpdatePSLPMC locked

The PMC locked manually. MC  grabbed lock instantaniously

  8429   Tue Apr 9 07:48:10 2013 SteveUpdatePSLPMC locked

Quote:

The PMC locked manually. MC  grabbed lock instantaniously

 PMC locked

Attachment 1: pmc10d.png
pmc10d.png
  8435   Wed Apr 10 07:37:33 2013 SteveUpdatePSLPMC locked

Quote:

Quote:

The PMC locked manually. MC  grabbed lock instantaniously

 PMC locked

 PMC locked.

Attachment 1: pmc4d.png
pmc4d.png
  11522   Fri Aug 21 08:38:37 2015 SteveUpdateIOOPMC locked

PMC needed to be locked manually.cheeky

Attachment 1: PMClocked.png
PMClocked.png
  6978   Mon Jul 16 16:41:49 2012 JenneUpdatePSLPMC locked in funny place - PSL laser temp changed

The PMC was unlocked earlier this morning, for ~20min, presumably from the rocks next door.  I relocked it.

Then, a few min ago, the PMC suddenly decided that it wouldn't lock with a transmission greater than ~0.7 .  I found that the laser temp adjust on the FSS screen was at -1.9ish.  I put it back to zero, and now the PMC locks happily again.  I think we got into a PSL mode-hopping temperature region on accident.

  6863   Sun Jun 24 23:42:31 2012 yutaUpdateComputer Scripts / ProgramsPMC locker

I made a python script for relocking PMC.
It currently lives in /opt/rtcds/caltech/c1/scripts/PSL/PMC/PMClocker.py.

I think the hardest part for this kind of locker is the scan speed. I could make the scan relatively fast by using pyNDS.
The basic algorithm is as follows.

1. Turns off the servo by C1:PSL-PMC_SW1.

2. Scans C1:PSL-PMC_RAMP using ezcastep.bin. Default settings for ezcastep is

ezcastep.bin C1:PSL-PMC_RAMP -s 0.1 0.01 10000

So, it steps by 0.01 for 10000 times with interval of 0.1 sec.

3. Get C1:PSL-PMC_PMCTRANSPD and C1:PSL-PMC_RAMP online 1 sec data using pyNDS.

4. If it finds a tall peak in C1:PSL-PMC_PMCTRANSPD, kills ezcastep.bin process, sets C1:PSL-PMC_RAMP to the value where the tall peak was found, and then turns on the servo.

5. If tall peak wasn't found, go back to 3 and get data again.

6. If C1:PSL-PMC_RAMP reaches near -7 V or 0 V, it kills previous ezcastep.bin process and turns the sign of the scan.

I tested this script several times. It sometimes passes over TEM00 (because of the dead time in online pyNDS?), but it locks PMC with in ~10 sec.
Currently, you have to run this to relock PMC because I don't know how to make this an autolocker.

I think use of pyNDS can be applied for finding IR resonance using ALS, too.
I haven't checked it yet becuase c1ioo is down, but ALS version lives in /users/yuta/scripts/findIRresonance.py. ALS may be easier in that we can use fast channels and nice filter modules.

Other scripts:
 I updated /opt/rtcds/caltech/c1/scripts/general/toggler.py. It now has "lazymode". When lazymode, it toggles automatically with interval of 1 sec until you Ctrl-c.

 Also, I moved damprestore.py from my users directory to /opt/rtcds/caltech/c1/scripts/SUS/damprestore.py. It restores suspension damping of a specified mirror when watchdog shuts down the damping.

  6872   Mon Jun 25 21:54:52 2012 DenUpdateComputer Scripts / ProgramsPMC locker

Quote:

I made a python script for relocking PMC.
It currently lives in /opt/rtcds/caltech/c1/scripts/PSL/PMC/PMClocker.py.

I thought we rewrite auto lockers once per year, but this time it took us only a month. I wrote it for PMC on May 24. Is it not working?

Could someone make it more clear why some scripts are written on bash, others on sh or python? I think we should elaborate a strict order. Masha and I can work on it if anyone else considers this issue as a problem.

  6873   Tue Jun 26 00:52:18 2012 yutaUpdateComputer Scripts / ProgramsPMC locker

Quote:

I thought we rewrite auto lockers once per year, but this time it took us only a month. I wrote it for PMC on May 24. Is it not working?

I know.
I just wanted to use pyNDS for this kind of scanning & locking situation.
c1ioo was down for the weekend and I couldn't test my script for ALS, so I used it for PMC.

But I think PMClocker.py can relock PMC faster because it can sweep C1:PSL-PMC_RAMP continuously and can get continuous data of C1:PSL-PMC_PMCTRANSPD.

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