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  12810   Tue Feb 7 19:14:59 2017 JohannesUpdateCDSvme crate backplane adapter board layout

After fighting with Altium for what seems like an eternity I have finished putting my vision of the vme crate backplane adapter board into an electronic format. It is dimensioned to fill the back space of the crate exactly. The connectors are panel mount and the PCB attaches to the connectors with screws, such that the whole thing will be mechanically much more stable than the current configuration. A mounting bracket will attach to horizontal struts that need to be installed in the crates, mechanical drawings to follow.

Attachment 1: vme_backplane.pdf
vme_backplane.pdf
  12829   Wed Feb 15 00:26:44 2017 JohannesUpdateDAQpanels and pcbs

I finished designing the PCBs for the VME crate back sides (see attached). The project files live on the DCC now at https://dcc.ligo.org/LIGO-D1700058. I ordered a prototype quantity (9) of the PCB printed and bought the corresponding connectors, all will arrive within the next two weeks. See also attached the front panels for the Acromag DAQ chassis and Lydia's RF amplifier unit (the lone +24V slot confuses me: I don't see a ground connector?). On the Acromag panel, six (3x2) of the DB37 connectors are reserved for VME hardware, two are reserve, and I filled the remaining space with general purpose BNC connectors for whatever comes up.

Attachment 1: acromag_chassis_panel.pdf
acromag_chassis_panel.pdf
Attachment 2: vme_backplane_panel.pdf
vme_backplane_panel.pdf
Attachment 3: rfAmp.pdf
rfAmp.pdf
  14496   Tue Mar 26 04:25:13 2019 JohannesUpdateUpgradec1susaux upgrade plan
Quote:

Main TODO items

  • Debug issue with Acromag DC power wiring
  • Complete wiring from chassis feedthroughs to Acromag terminals, following this wiring diagram
  • Check/set the configuration of each Acromag unit using the software on the Windows laptop
  • Set the analog channel calibrations in the EPICS database file
  • Test each channel ex situ. Chub and I discussed an idea to use two DB-37F breakout boards, with the wiring between the board terminals manually set. One DAC channel would be calibrated and driven to test other ADC channels. A similar approach could be used for the digital input/output channels.

Just a few remarks, since I heard from Gautam that c1susaux is next in line for upgrade.

All units have already been configured with IP addresses and settings following the scheme explained on the slow controls wiki page. I did this while powering the units in the chassis, so I'm not sure where the short is coming from. Is the power supply maybe not sourcing enough current? Powering all units at the same time takes significant current, something like >1.5 Amps if I remember correctly. These are the IPs I assigned before I left:

Acromag Unit IP Address
C1SUSAUX_ADC00 192.168.115.20
C1SUSAUX_ADC01 192.168.115.21
C1SUSAUX_ADC02 192.168.115.22
C1SUSAUX_ADC03 192.168.115.23
C1SUSAUX_ADC04 192.168.115.24
C1SUSAUX_ADC05 192.168.115.25
C1SUSAUX_ADC06 192.168.115.26
C1SUSAUX_ADC07 192.168.115.27
C1SUSAUX_ADC08 192.168.115.28
C1SUSAUX_ADC09 192.168.115.29
C1SUSAUX_DAC00 192.168.115.40
C1SUSAUX_DAC01 192.168.115.41
C1SUSAUX_DAC02 192.168.115.42
C1SUSAUX_DAC03 192.168.115.43
C1SUSAUX_BIO00 192.168.115.60
C1SUSAUX_BIO01 192.168.115.61
C1SUSAUX_BIO02 192.168.115.62

I used black/white twisted-pair wires for A/D, red/white for D/A, and green/white for BIO channels. I found it easiest to remove the blue terminal blocks from the Acromag units for doing the majority of the wiring, but wasn't able to finish it. I had also done the analog channel calibrations using the windows untility using multimeters and one of the precision voltage sources I had brought over from the Bridge labs, but it's probably a good idea to check it and correct if necessary. I also recommend to check that the existing wiring particularly for MC1 and MC2 is correct, as I had swapped their order in the channel assignment in the past.

While looking through the database files I noticed two glaring mistakes which I fixed:

  1. The definition of C1SUSAUX_BIO2 was missing in /cvs/cds/caltech/target/c1susaux2/C1SUSAUX.cmd. I added it after the assignments for C1SUSAUX_BIO1
  2. Due to copy/paste the database files /cvs/cds/caltech/target/c1susaux2/C1_SUS-AUX_<OPTIC>.db files were still pointing to C1AUXEX. I overwrote all instances of this in all database files with C1SUSAUX.

 

  97   Mon Nov 12 23:44:19 2007 JohnUpdatePSLISS

Quote:

After John soldered a 3.7 MHz notch filter onto the ISS board, I took a quick TF and RIN measurement. The out-of-loop RIN is attached, including a dark noise trace, and with the gain slider at 10dB. The UGF is 35kHz with a phase margin of 30deg. John is currently doing a more thorough inspection, and will detail his findings in a subentry.


No progress on the ISS tonight. I tried to implement a new filter (attached)to try and gain some phase before the notch. If anything this made things worse. More work is needed.

The ISS loop is off and the power is off at the chassis.
Attachment 1: ISSfilter.jpg
ISSfilter.jpg
  98   Tue Nov 13 14:33:40 2007 JohnUpdatePSLISS filter
The transfer function from 'In Loop Error Point Monitor' to TP3 the filter out test point on the ISS board.

-33dB at 3.715MHz.
Attachment 1: PB130035.JPG
PB130035.JPG
Attachment 2: DSC_0165.JPG
DSC_0165.JPG
  104   Thu Nov 15 04:18:11 2007 JohnSummaryPSLPMC cavity pole measurements
In connection with our work on the ISS I attempted to measure the PMC cavity pole.

I swept the PMC PZT and looked at the transmission through the cavity on the ISS Monitor diode (which is now back on the table, feel free to remove it again tomorrow).

To avoid thermal effects I reduced the laser power using the half wave plate at the laser ouput (rotated from 6 deg to 340deg).

I swept the PZT using the triangle wave command "trianglewave C1: PSL-PMC_RAMP -3.5 3.3 20 200". I noticed that the functional form of the resonances deteriorated over the duration of the excitation. Each sweep was able to capture just over one FSR. The resonances were a little close to the 'points' of the triangle wave for my liking although I don't think PZT hysteresis was a big factor.

Looking at the data the peaks are not of uniform width across a sweep or between consecutive sweeps. Hence any results from this mesurement are not particularly useful. I can't be sure if this was due to misalignments, thermal effects, higher order mode content or some other affect.

Rob suggests sweeping the laser frequency using the NPRO PZT instead.
Attachment 1: Peaks.jpg
Peaks.jpg
  107   Thu Nov 15 18:23:55 2007 JohnHowToComputersSwap CAPS and CTRL on a Windows 2000/XP machine
I've swapped ctrl and caps on the four control room Windows machines. Right ctrl is unchanged.



Start menu->Run "regedit"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Keyboard Layout

Click on the KeyboardLayout entry.

Edit->New Binary Value name it Scancode Map.

Then select the new Scancode Map entry.

Edit menu->Modify Binary Data.

In the dialog box enter the following data:

0000: 00 00 00 00 00 00 00 00
0008: 03 00 00 00 3A 00 1D 00
0010: 1D 00 3A 00 00 00 00 00

Exit the Registry Editor. You need to log off and then on in XP (and restart in Windows 2000) for the changes to be made.
  108   Thu Nov 15 18:36:48 2007 JohnSummary PSL table work
I've rotated the lambda/2 plate to 340deg (from 6 deg) and blocked one arm of the Mach-Zender. Undo both if you need to.
  116   Tue Nov 20 10:11:33 2007 JohnSummaryPSLPMC pole measurements
We measured the PMC pole in the following way.

1. Reduced laser power by rotating lambda/2 plate at laser output. Thermal effects in the PZT distort resonance peaks. Reducing power too much leads to problems with digitisation error.

2. Sweep NPRO PZT (C1: PSL-FSS_INOFFSET) using trianglewave. Record ramp, PMC transmission and reference cavity transmission ('C1: PSL-FSS_FAST','C1: PSL-ISS_INMONPD_F','C1: PSL-FSS_RCTRANSPD_F).

3. Since the PZT cannot sweep a full FSR in the PMC we looked at the sideband resonances within the reference cavity to calibrate the actuator.
Result: 7.35 +/- 0.22 MHz/V

4. Use #3 to calibrate the x axis of the PMC transmission.

5. Fit PMC resoances to an Airy function to get finesse. Take an average, weighted according to the resnorm. Calculate cavity pole frequency.
Result: 380kHz +/- 59kHz. This corresponds to a finesse of ~936. According to this plot the nominal pole is at 488kHz and the finesse is 732.

This is by no means a definitive measurement due to the misshapen resonance peaks recorded.
Attachment 1: FittedPMCPeak.jpg
FittedPMCPeak.jpg
  119   Tue Nov 20 18:02:54 2007 JohnSummaryComputersPSL_Main screen
I've updated the PSL_MAIN screen. The old version may be found in cvs/cds/caltech/medm/old/medm/psl.
Attachment 1: PSL_Screen.tif
PSL_Screen.tif
  120   Tue Nov 20 18:35:20 2007 JohnHowToComputersMatLab in Emacs
If you can't get MatLab to run in emacs try adding the following to the .emacs file

(setq matlab-shell-command-switches '("-nojvm"))

This stops the gui opening.

To start MatLab type M-x matlab-shell.
To enter MatLab mode M-x matlab-mode.

I've done this on LINUX3.

To run MatLab in emacs under windows one can use MatLabShell http://www.cs.umb.edu/~ram/matlabShell/index.html
  259   Thu Jan 24 12:50:50 2008 JohnSummaryTreasureSugar Napoleons
Some pictures from the group meeting yesterday.
Attachment 1: Sweeties.pdf
Sweeties.pdf
  271   Sat Jan 26 02:02:43 2008 JohnSummaryGeneralNew Channels
I added the following channels.

# C1ASC_QPDs
[C1:SUS-ETMY_QPDSUM_MON]
[C1:SUS-ETMY_QPDYAW_MON]
[C1:SUS-ETMY_QPDPIT_MON]

[C1:SUS-ETMX_QPDSUM_MON]
[C1:SUS-ETMX_QPDYAW_MON]
[C1:SUS-ETMX_QPDPIT_MON]

The old .ini file is /cvs/cds/caltech/chans/daq/C0EDCU_26_1_2008.ini
  272   Sat Jan 26 02:08:53 2008 JohnOmnistructureLSCFibres
There is now a fibre running from the SP table to the ISCT at the Y-end. In the coming days I will try to mode match the beam from this fibre into the arm through ETMY. To achieve this I will be altering the optical layout of this table.
  275   Sat Jan 26 18:48:43 2008 JohnSummaryComputersRestart iscepics
iscepics died this afternoon. We restarted it and restored settings from yesterday. I've written up instructions in the wiki.
  276   Sat Jan 26 22:00:03 2008 JohnUpdateGeneralLSC-TRY_OUT and ETMY-QPD
In the path from the ETM to the trans PD and QPD at the Y end I have replaced a BS1-1064-10-2037-45P with a polariser. The power falling on these diodes has been reduced. When the arm is locked in its nominal state the transmitted power is now less than 1.

This polariser should serve as an injection point for the auxiliary arm locking. I am attempting to use crossed polarisations to separate this loop from the main arm light.
  288   Thu Jan 31 12:39:14 2008 JohnConfigurationGeneralY arm test mass cameras
I've adjusted the test mass cameras on the y arm to make the beam injected through ETMY more visible.
  290   Fri Feb 1 10:43:05 2008 JohnUpdateEnvironmentConstruction work
The boys next door have some bigger noisier toys.
Attachment 1: DSC_0433.JPG
DSC_0433.JPG
  293   Fri Feb 1 17:17:05 2008 JohnSummaryPSLMach-Zender tweaking
I helped Rob adjust the alignment of the Mach-Zender to try and reduce any AM on the laser light. Our goal was to reduce the large offsets in the DD signals.

We reduced the MZ refl from 0.54 to 0.39. We were able to re-lock the mode cleaner without problems. We then centred the WFS heads.

No change in the DD signal offsets.
  294   Sat Feb 2 14:11:27 2008 JohnSummaryComputersOPTLEVmaster screen
I changed the layout of the optlev master screen. The old version is /cvs/cds/caltech/medm/old/C1ASC_OPTLEVmaster080202.adl
  296   Mon Feb 4 22:01:57 2008 JohnSummaryLSCFibres auxiliary locking - Fibers
I managed to couple ~75% of the light transmitted from the y arm, through the fibre, back to the SP table. I hoped that this would be a good way to match the beam from the fibre into the arm. Still no flashes. It looks like the cameras just aren't sensitive enough.
  304   Sat Feb 9 13:05:48 2008 JohnSummaryIOOPMC camera/ HEPA
I replaced the Gig-E camera on the PMC trans beam. The PZT was close to railing and I wanted to adjust it. I just did a quick job, there is a little scattered light on the image. If Joe is finished with the Gig-E I'll take another look at it.

The HEPA in the PSL table was turned off for some reason. I turned it back on.
  305   Sat Feb 9 13:32:07 2008 JohnSummarySUSAll watchdogs tripped
When I arrived this afternoon the watchdogs had tripped on all optics. I reset them and enabled the coil currents.

I had to adjust the alignment of the mode cleaner to get it to lock.
  315   Wed Feb 13 20:37:11 2008 JohnUpdateLSCFibre locking - Fiber
Sam and I observed fringes in the light reflected from the Y arm. These fringes are due to the sidebands and not the carrier. To improve matters we plan to reduce the RF AM and increase our modulation index.
  324   Tue Feb 19 18:28:41 2008 JohnUpdatePEMMore seismic in Baja California
Steve spotted more activity from the same quake.

Reset watchdog on ETMY.
  328   Thu Feb 21 18:29:28 2008 JohnSummaryGeneralHP Network Analyser Analyzer
The HP 4195A network analyser may be broken, measurements below 150MHz are not reliable. Above 150MHz everything looks normal. This may be caused by a problem with its output (the one you'd use as an excitation) which is varying in amplitude in a strange way.

Analyzer
  342   Wed Feb 27 22:05:03 2008 JohnUpdateLSCAuxiliary locking
A summary of the status of the auxiliary arm locking effort.

To help with lock acquisition we are attempting to independently lock the Y arm using light injected through ETMY. At present this secondary light source is an NPRO laser situated on the SP table. The laser light is transported to the ETM using a single mode optical fibre. In the future we might pick off some PSL light and apply a frequency shift.

We have been able to successfully mode match the fibre beam into the cavity and have been attempting lock the cavity using standard PDH signals (phase modulation sidebands are added to the light before it enters the fibre).

As yet no acceptable error signals have been produced. The demodulated RF signal is showing a time varying, bipolar dc offset.

We have minimised the residual amplitude modulation of the EOM but we expect small signals due to the undercoupled nature of the system, it could be that whatever RFAM still present is varying with time and causing this behaviour. We are also able to produce similar offsets by stressing (i.e. bending, shaking) the fibre. Could it be that the fibre is somehow converting PM into AM? Are we seeing etalon effects in the fibre or elsewhere?

If we cannot make any further progress with the existing setup we shall move the NPRO to the ETM table and try again. We are also looking into purchasing some other types of fibre.

Other things to consider are injecting through POY or using some other wavelength - neither seems obviously better.

Fiber, behavior
  348   Fri Feb 29 13:51:17 2008 JohnSummaryLSCPD6 response
I checked the response of PD6 using the AM laser. It looks happy enough.

16 averages
-10dBm source power
77.3mV dc on the diode
  359   Wed Mar 5 12:35:09 2008 JohnSummaryComputer Scripts / ProgramsPlot photodiode responses in MatLab
A matlab function to plot the responses of photodiodes. There's still plenty of room for improvement but it should work for all our diodes without any changes. You may want to adjust which points are used in the fit to remove time delay.




% Plot data from diode response measurements
function out = diodeplot(f_Hz,mag_dB,phase_deg,f_beat_MHz)

% $$$ clear all
% $$$ close all
% $$$ clc
% $$$
% $$$
% $$$ mag = dlmread('D:\40m\PD6\M7.txt','\t', 15, 0);
% $$$ phase = dlmread('D:\40m\PD6\P7.txt','\t', 15, 0);
% $$$
% $$$ % Frequency i.e. x-axis
% $$$ f = mag(:,1);
% $$$
% $$$ % Magnitude in dB
% $$$ mag_dB = mag(:,2);
% $$$
% $$$ % Phase in degrees
% $$$ phase_deg = phase(:,2);
% $$$
% $$$ % Frequencies of interest
% $$$ f_beat_MHz = [33 133 166 199]*1e6;
% $$$
% $$$ diodeplot(f, mag_dB, phase_deg, f_beat_MHz)

% x axis limits
xmin = 10e6;
xmax = 500e6;

% Unwrap phase
phase_deg = (180/pi)*unwrap((pi/180)*phase_deg);

%Find values at our freqeuncies of interest
Mag_f_beat = interp1(f_Hz,mag_dB,f_beat_MHz);

% Remove the time delay from the phase data
% (May want to adjust which points are selected here)

straight = @(a, x) a(1) * x + a(2);

xdata = f_Hz;
ydata = phase_deg;

aguess = [10 0.1];
a = lsqcurvefit(straight,aguess,xdata,ydata);
fit = straight(a,xdata);

phase_deg = phase_deg-fit;

figure(1)
ha = axes('units','normalized','position',[0 0 1 1]);
uistack(ha,'bottom');
I=imread('PDbw.jpg');
hi = imagesc(I);
colormap gray
set(ha,'handlevisibility','off', ...
'visible','off')
plot(xdata,ydata,'r')
hold on
plot(xdata,fit,'k')
plot(xdata,phase_deg,'b')
hold off
ylabel('Phase/ degrees', 'FontSize',12)
xlabel('Frequency/ Hz', 'FontSize',12)
title('Removing the time delay','FontSize',16)
legend('data','fit','data-fit',0)
set(hi,'alphadata',.35)
set(gca,'Color','None')
box off




figure(2)
set(gcf,'Color', [1 1 1])
subplot(4,1,[1 3])

semilogx(f_Hz,mag_dB,'k','LineWidth',2.5)
title('Response of PD6','FontSize',16)
ylabel('Magnitude/ dB', 'FontSize',12)
xlim([xmin xmax])
grid

MagLayout = get(gca, 'Position');
YLimits = get(gca, 'YLim') ;
LabelExt = [];

for ivar = 1:length(f_beat_MHz);

a = text(f_beat_MHz(ivar),1.05 * min(Mag_f_beat),...
sprintf('%2.1fdB @ %dMHz', Mag_f_beat(ivar),f_beat_MHz(ivar)/1e6),...
'FontSize',10,'FontWeight','Bold','HorizontalAlignment','right',...
'VerticalAlignment','top','BackgroundColor',[.7 .9 .7],...
'Margin',0.5, 'Rotation',90);
LabelExt = [LabelExt; get(a,'Extent')];
LabelPos = get(a,'Position');

end

% Change YLim so that it is around the bottom of the labels
% There must be a better way
set(gca, 'YLim', [min(LabelExt(:,2)) YLimits(2)])

% Remove the last tick mark so that it doesn't overlap with the
% +180 of the phase plot
YTickLabelNew = str2num(get(gca, 'YTickLabel'));
YTickNew =[[] YTickLabelNew(2:end) ];
set(gca,'XTickLabel', [], 'YTick', YTickNew)

% Add lines now we know what the YLims are
for ivar = 1:length(f_beat_MHz);
line([f_beat_MHz(ivar) f_beat_MHz(ivar)], get(gca, 'YLim'))
end

subplot(4,1,4)
semilogx(f_Hz,phase_deg,'r','LineWidth',2.5)
xlim([xmin xmax])
ylabel('Phase/ degrees', 'FontSize',12)
xlabel('Frequency/ Hz', 'FontSize',16)
grid
PhaseLayout = get(gca, 'Position');
PhaseLayout(4) = MagLayout(2)-PhaseLayout(2);

% Make the top of the phase plot align to the bottom of the
% magnitude plot
set(gca, 'Color', 'None', 'Position',PhaseLayout, 'YTick',[-180:45: ...
180])
set(gcf,'units','normalized','outerposition',[0 0 1 1]);
Attachment 3: PDbw.jpg
PDbw.jpg
  360   Wed Mar 5 12:51:48 2008 JohnSummaryLSCInitial Ligo Arm finesse versus lambda
I've taken the coating recipes for the initial ligo arm cavity from Rana's web page (ligo.caltech/edu/~rana/mat/)
and plotted the finesse as a function of wavelength. There is some uncertainty over the indices of refraction but
the main conclusion remains unchanged - i.e. it appears that using other wavelengths will be difficult.
Stefan is looking at how to tune the layers of any new mirrors to make dichroic optics.
Attachment 1: FofLambdaLIGOI.jpg
FofLambdaLIGOI.jpg
  367   Mon Mar 10 20:46:41 2008 JohnConfigurationLSCETMY Trans PD & QPD
I've placed a 10% reflector in the path from ETMY to the trans and quadrant photodiodes.
  377   Thu Mar 13 18:20:29 2008 JohnUpdateGeneralNew Focus 4003 EOM 29.489MHz
I measured the modulation index as a function of drive power using an OSA. Agrees well with spec of 0.2 rad/V.
  396   Sun Mar 23 00:56:42 2008 JohnUpdateLSCMore on 3f
We ended our last attempt at 3f locking concerned about the beam size on PD6. I investigated tonight. The beam was not obviously overfilling the diode and a quick tweak of the steering mirror revealed a decent plateaux. Nevertheless we decided to try a different approach to see if we found the same problems as before on a different diode.

This time our 3f diode was Refl 33. I put a splitter on the output of the diode at the LSC rack sending one half into the usual refl 33 board, the other into refl DD 199 (which is demodulating at 99Mhz).

I got as far as handing off PRC to the 3f signal in lock. More work needed.
  399   Mon Mar 24 20:15:03 2008 JohnSummaryComputersc1susvme2
c1susvme2 isn't behaving itself. It keeps getting out of sync and/or giving a red status light.

After going through the usual restart procedures a few times (unsuccessfully) we power cycled the c1susvme & c1sosvme crates. We think everything came back okay.

We still can't get the status and CRC (cyclic redundancy check) to return to normal on c1susvme2. If Alex is around tomorrow please ask him to take a look.
  402   Tue Mar 25 15:56:09 2008 JohnUpdateTreasureAssorted pictures
Some pictures scavenged from the D40.
Attachment 1: D40.pdf
D40.pdf D40.pdf
  405   Wed Mar 26 22:26:15 2008 JohnUpdateComputersc1susvme
I removed the fan and tweaked the timing cables to see if they were the source of our problems. I saw no effect. I'm leaving the fan off for the moment to see if that helps. It is on top of the filing cabinet next to my desk.
  503   Thu May 29 15:58:44 2008 JohnSummaryIOOMC realignment
I repeatedly adjusted the yaw of the upper mirror on the input periscope and re aligned the MC. With the PRM aligned I tried to optimise MC transmission and DC refl simultaneously. I subsequently centred the beams on WFS1/2. Attached is a 30 day trend of MC alignment and transmission.
  536   Tue Jun 17 22:00:53 2008 JohnHowToPSLProblems turning MZ servo on/off
We were unable to toggle the MZ servo on/off (Blank/Normal) from MEDM. Pushing on the Xycom board and cables changed the fault from constant to intermittent. At least one lock loss has been caused by a MZ glitch.
  557   Tue Jun 24 15:15:09 2008 JohnSummaryLSCLocking efforts
Rob, Rana, John

In the past week or so we've been working on reducing the CARM offset using a DC signal (SPOB DC).
We were able to get up to arm powers of around 30 (where a single arm cavity lock is a power of 1)
before instability set in and we would lose lock for, as yet, unknown reasons.

In recent nights locking efforts have taken a few backward steps.

Since last Thursday engaging the AO path has proved troublesome, i.e. engaging it would instantly
cause loss of lock. This seems to be related to problems with the mode cleaner servo. For the past
few nights it has been behaving strangely and could not be operated with the usual super boost stages.
Last night the situation was improved. MC boost stages could be used and the AO path engaged. The
cause of this problem and its spontaneous resolution are not understood.

Last night we were unable to switch CARM to SPOB DC. I've attached a spectrum of the MC2 length signal.
This path is being used for CARM and so gives an indication of the frequency noise after the mode
cleaner. At the moment the plot is calibrated in units of Rana's gut feeling. We already tested to see if
any of the excess noise was introduced by the WFS. No evidence was found. We'll try to make a useful
calibration soon and see if our problems are related to excess frequency noise.

Another realisation from last night was the effect of arm detuning on the analogue CARM path. When CARM is detuned
the coupled cavity pole removes an extra 90 degrees of phase. The digital path has the `moving zero' to compensate
for this. The analogue path has no such compensation and can therefore become unstable at moderate detunings.
We propose trying to reduce the CARM offset further before engaging the analogue path. This will give higher
gain and move the UGF to a region of increased phase margin.
Attachment 1: mcl080623.png
mcl080623.png
  562   Wed Jun 25 01:30:19 2008 JohnSummaryIOOFrequency noise after the MC
I made some (very) rough estimates of the contribution made to the noise after the mode cleaner by three sources.

Seismic noise - how much of the signal is due to the mode cleaner compenstaing for seismic disturbance of CARM.
Actuator noise - coil drivers and DAC noise.
MC_F - estimate of MC_F suppressed by the loop gain.
Attachment 1: MC2noise080623.png
MC2noise080623.png
  568   Wed Jun 25 13:56:56 2008 JohnSummaryLockingTuesday night locking
Rob, John

Worked to try and reduce the CARM offset using the dc arm transmissions before changing to SPOB DC. This proved somewhat unsuccessful, the offset couldn't be reduced to more than five (arms storing 5x more power than single arm cavity lock).
  573   Thu Jun 26 12:30:40 2008 JohnSummaryLockingCARM on REFL_DC
Idea:

Try REFL_DC as the error signal for CARM rather than PO_DC.

Reasoning:

The PO signal is dominated by sideband light when the arms are detuned so that any misalignment in the recycling cavity introduces spurious signals. Also, the transfer function from coupled cavity excitation to REFL signal is not so steep and hence REFL should give a little more phase. Finally, the slope of the REFL signal should make it easier to hand over to RF CARM.

Conclusion:


The REFL signal showed no clear improvement over PO signals. We've gone back to PO.


During the night we also discovered that the LO for the MC loop is low.
  582   Fri Jun 27 14:36:39 2008 JohnSummaryLocking 
Rob, Yoichi, John

Some progress last night:

Switched back to SPOB_DC for CARM.

Shaped the MC LSC loop to reduce excess noise in the 20-30Hz band. Likely the most significant change.
Could this be due to fan noise from the laptop on the SPOB table?

Brought in the AO path earlier (at low gain).

Reduced offset to 6 and increased MC gain before handing off to SPOB. Ramped up AO and MC gain then switched off the
moving zero.

Looks like PD11 is the most promising candidate for RF CARM although the demod phase needs attention.
Attachment 1: gettingcloser.png
gettingcloser.png
  586   Fri Jun 27 19:59:44 2008 JohnUpdateComputersc1iovme
C1susvme2 and C1iovme crashed which sent the optics swinging and tripped the watchdogs.

Koji and I were able to restore c1susvme2 without any trouble.

We have been unable to revive c1iovme. We have tried telneting in and running startup.cmd,
the process runs for a while then hangs with "DAQ init failed -- exiting".

Resetting the board doesn't help. I didn't try keying the whole crate.

All optics are back to normal with damping restored.
  588   Sat Jun 28 14:56:44 2008 JohnUpdateComputersini files
In short, I was editing the ini files yesterday evening, I didn't e-log it and after some investigation this afternoon it apears
that I am to blame for all the computer problems which followed.


I wanted to edit C0EDCU.ini and C1IOOF.ini to change C1: PSL-FSS_FAST to a fast channel as C1: PSL-FSS_FAST_F
was dead.

I opened these files and made backups. It appears this is where it all went awry. My backup for C1IOOF
is called C1IOO.ini.090627 i.e. missing the F.

Later c1susvme2 and c1iovme crashed. After failing to bring c1iovme back I wondered if my edits had
caused the problems so I restored the back up files. It appears that here I wrote over C1IOO with my backup of
C1IOOF (presumably because I had made a typo in the name).

To remedy the situation we could restore C1IOO from e.g. chans/archive/C1IOO_080618_160028.ini

No excuses for not e-logging this activity.
  589   Sat Jun 28 23:23:50 2008 JohnUpdateComputersRebooting
All of the computers are now showing green lights.

Remaining problems:

Alignment scripts are failing with "ERROR: LDS - NDS server error #13"
I think this is a server transmission error.

Dataviwer shows all channels as zero.
  591   Sun Jun 29 11:31:52 2008 JohnSummaryPSLISS
I reduced the gain of the ISS (C1: PSL-ISS_VGAGAIN) from 5dB to 2dB. Any higher and it constantly saturates.
  595   Sun Jun 29 19:53:26 2008 JohnSummaryPSLISS

Quote:
I reduced the gain of the ISS (C1: PSL-ISS_VGAGAIN) from 5dB to 2dB. Any higher and it constantly saturates.


Seemed to go back to normal after the frame builder came back.
  596   Sun Jun 29 20:09:40 2008 JohnSummaryIOOmcup and mcdown indicators
I edited the mcup and mcdown scripts so that C1IFO_STATE shows when these scripts are running.

I also added indicators to the LockMC screen.
Attachment 1: mcscreen.png
mcscreen.png
Attachment 2: ifostate.png
ifostate.png
  598   Mon Jun 30 01:49:06 2008 JohnUpdateIOOMC work
I'm in the process of aligning the mode cleaner/ input beam.

I turned off the WFS and cleared their histories, adjusted the input periscope and re-aligned the mode-cleaner accordingly.
I then unlocked the cavity and centred the beams on the WFS.

MC transmission is ~3.3 and the REFL beam looks a little better.

However, turning the WFS on now lowers the transmission. More thought tomorrow.

I'm leaving the MC locked with WFS off.
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