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ID Date Author Type Categoryup Subject
  13834   Fri May 11 18:17:07 2018 gautamUpdateDetCharAUX laser PLL setup

[koji, gautam]

As discussed at the meeting earlier this week, we will use some old *MOPA* channels for interfacing with the PLL system Jon is setting up. He is going to put a sketch+photos up here shortly, but in the meantime, Koji helped me identify a channel that can be used to tune the temperature of the Lightwave NPRO crystal via front panel BNC input. It is C1:PSL-126MOPA_126CURADJ, and is configured to output between +/-10V, which is exactly what the controller can accept. The conversion factor from EPICS value to volts is currently set to 1 (i.e. EPICS value of +1 corresponds to +1V output from the DAC). With the help of the wiring diagram, we identified pins 3 and 4 on cross-connect #J7 as the differential outputs corresponding to this channel. Not sure if we need to also setup a TTL channel for servo ENABLE/DISABLE, but if so, the wiring diagram should help us identify this as well. 

The cable from the DAC to the cross-connect was wrongly labelled. I fixed this now.

  15309   Wed Apr 22 13:52:05 2020 gautamUpdateDetCharSummary page revival

Covid 19 motivated me to revive the summary pages. With Alex Urban's help, the infrastructure was modernized, the wiki is now up to date. I ran a test job for 2020 March 17th, just for the IOO tab, and it works, see here. The LDAS rsync of our frames is still catching up, so once that is up, we can start the old condor jobs and have these updated on a more regular basis.

  15370   Wed Jun 3 11:20:19 2020 gautamUpdateDetCharSummary pages

Summary:

The 40m summary pages have been revived. I've not had to make any manual interventions in the last 5 days, so things seem somewhat stable, but I'm sure there will need to be multiple tweaks made. The primary use of the pages right now are for vacuum, seismic and PSL diagnostics.

Resources:

Caveats:

  • Intermittent failures of cron jobs
    • The status page relies on the condor_q command executing successfully on the cluster end. I have seen this fail a few times, so the status page may say the pages are dead whereas they're actually still running.
    • Similarly, the rsync of the pages to nodus where they're hosted can sometimes fail.
    • Usually, these problems are fixed on the next iteration of the respective cron jobs, so check back in ~half hour.
  • I haven't really looked into it in detail, but I think our existing C1:IFO-STATE word format is not compatible with what gwsumm wants - I think it expects single bits that are either 0 or 1 to indicate a particular state (e.g. MC locked, POX and POY locked etc). So if we want to take advantage of that infrastructure, we may need to add a few soft EPICS channels that take care of some logic checking (several such bits could also be and-ed together) and then assume either 0 or 1 value. Then we can have the nice duty cycle plots for the IMC (for example).
  • I commented out the obsolete channels (e.g. PEM MIC channels). We can add them back later if we so desire.
  • For some reason, the jobs that download the data are pretty memory-heavy: I have to request for machines on the cluster with >100 GB (yes 💯GB) ! of memory for the jobs to execute to completion. The frame-data certainly isn't so large, so I wonder what's going on here - is GWPy/GWsumm so heavy? The site summary pages run on a dedicated cluster, so probably the code isn't built for efficiency...
  • Weather tab in PEM is still in there but none of those channels mean anything right now.
  • The MEDM screenshot stuff is commented out for now too. This should be redone in a better way with some modern screen grab utilities, I'm sure there are plenty of python based ones.
  • There seems to be a problem with the condor .dag lockfile / rescue file not being cleared correctly sometimes - I am looking into this.
  15696   Wed Dec 2 18:35:31 2020 gautamUpdateDetCharSummary page revival

The summary pages were in a sad state of disrepair - the daily jobs haven't been running for > 1 month. I only noticed today because Jordan wanted to look at some vacuum trends and I thought summary pages is nice for long term lookback. I rebooted it just now, seems to be running. @Tega, maybe you want to set up some kind of scripted health check that also sends an alert.

  15812   Wed Feb 17 13:59:35 2021 gautamUpdateDetCharSummary pages

The summary pages had failed because of a conda env change. We are dependent on detchar's conda environment setup to run the scripts on the cluster. However, for some reason, when they upgraded to python3.9, they removed the python3.7 env, which was the cause of the original failure of the summary pages a couple of weeks ago. Here is a list of thoughts on how the pipeline can be made better.

  1. The status checking is pretty hacky at the moment.
    • I recommend not using shell via python to check if any condor jobs are "held".
    • Better is to use the dedicated python bindings. I have used this to plot the job durations, and it has worked well.
    • One caveat is that sometimes, there is a long delay between making a request via a python command, and condor actually returning the status. So you may have to experiment with execution times and build some try/except logic to catch "failures" that are just the condor command timing out and not an actual failure of the summare jobs.
  2. The status check should also add a mailer which emails the 40m list when the job is held. 
    • With htcondor and python, I think it's easy to also get the "hold reason" for the job and add that to the mailer.
  3. The job execution time command is not executing correctly anymore - for whatever reason, the condor_history command can't seem to apply the constraint of finding only jobs run by "40m", although running it without the constraint reveals that these certainly exist. Probably has to do with some recent upgrade of condor version or something. This should be fixed.
  4. We should clear the archive files regularly. 
    • The 40m home directory on the cluster was getting full. 
    • The summary page jobs generate a .h5 archive of all the data used to generate the plots. Over ~1 year, this amounts to ~1TB.
    • I added the cleanArchive job to the crontab, but it should be checked.
    • Do we even need these archives beyond 1 day? I think they make the plotting faster by saving data already downloaded locally, but maybe we should have the cron delete all archive 
  5. Can we make our own copy of the conda env and not be dependent on detchar conda env? The downside is that if something dramatic changes in gwsumm, we are responsible for debugging ourselves.

Remember that all the files are to be edited on nodus and not on the cluster.

  16893   Mon Jun 6 16:09:23 2022 ranaConfigurationDetCharSummary Pages: seis BLRMS

I updated the config file c1pem.ini in /users/public_html/detcharsummary/ConfigFiles, and commited it so I hope it works, but I did not have git push permissions. Does anyone know what is the idea here? Should we do our own personal git clone and modify that way or shoudl we do it with the control account.

Wiki needs to clear out all the outdated information on this workflow.

The changes are to make the y-scales useful. Currently, all of the past seis BLRMS plots are not so useful because the scales have not been set based on the actual signal levels. Let's see if this works, and we  can re-evaluate after a few weeks.

  145   Fri Nov 30 11:44:57 2007 robConfigurationElectronicsETMX oplev
In the interests of getting the Xarm alignment script working again, I reset the local damping gains for the test masses to their previous known working values (1), then I noticed that the ETMX oplev was dead. Since the scripts use the oplev motion as a readback for the optic motion, this means the script was basically blindly swinging the optics around. Some monkeying around with swapping HeNe power supplies eventually led to the conclusion that the power strip is funky, since the laser works when plugged into another power strip. Even weirder, the HeNe and the power supply indicator light have some sort of XOR relationship going on. When one works, the other doesn't. Steve will sort out this confusion later; we're good for now.
  146   Fri Nov 30 13:46:50 2007 robConfigurationElectronicsETMX oplev dead again

Quote:
In the interests of getting the Xarm alignment script working again, I reset the local damping gains for the test masses to their previous known working values (1), then I noticed that the ETMX oplev was dead. Since the scripts use the oplev motion as a readback for the optic motion, this means the script was basically blindly swinging the optics around. Some monkeying around with swapping HeNe power supplies eventually led to the conclusion that the power strip is funky, since the laser works when plugged into another power strip. Even weirder, the HeNe and the power supply indicator light have some sort of XOR relationship going on. When one works, the other doesn't. Steve will sort out this confusion later; we're good for now.


Ech. The HeNe quit again. Let's replace it and see what happens.
  147   Fri Nov 30 19:11:05 2007 ranaConfigurationElectronicsETMX oplev dead again
I removed the ETMX HeNe and put in on a test table and it fired up fine. In its
previous location the light on the HeNe power supply was not lighting up. If
that's still on over the weekend we'l blame the power strip; the HeNe is a JDS
2.7 mW laser from 2002.
  165   Wed Dec 5 13:49:08 2007 albertoUpdateElectronicsRF AM PD lines monitor
In the last weeks Iíve been working on the design of an electronic board to measure directly the power of the main spectral lines on of the RF-AM photodiode from as many independent outputs. The idea is to have eventually a monitor channel in the CDS network for the power of each line.
Looking at at the spectrum from the RF-AM PD (see attached plot), there are 5 main lines:
Frequency
3 fsr = 33 195 439 Hz
4 fsr = 66 390 878 Hz
12 fsr = 132 781 756 Hz
15 fsr = 165 977 195 Hz
18 fsr = 199 172 634 Hz

Two main approaches have been proposed for the circuit depending on the way followed to isolate the lines:
1) Filters: the frequencies are separated by narrow notch filters, then a diode bridge rectifies and a low pass filter extracts the DC component.
2) Mixers: for each frequency there is a mixer driven by a copy of the correspondent modulation frequency provided by the function generators (the Marconi). The mixers automatically give the DC component of the rectified signals.
Because of the phase lags that we should compensate if we used mixers, we would prefer the first approach, if it works.
Starting with a tolerance of about 10% between the channels, the spectrum (see attachment) sets the constraint to the filterís suppression:
Filter central frequency [MHz]******Suppression within 30 Mhz [dB]
33*********************************-7-20 = -27
66**********************************7-20 = -13
133*********************************12-20 = -8
166********************************-12-20 = -32
199*********************************10-20 = 10

So far Iíve tried two kinds of designs for the filters, Butterworth (see attachment) and LC and I'm measuring transfer functions tuning the components to match the central frequency and the bandwdth of the filters with the requirements.

The frequencies weíre dealing with are rather high and several adjustments had to be done to the measurement system in order to shield the circuit from the impedance of the input and the output line (i.e., amplifier turned out to be necessary). Also, an the mixer had to be replaced to an RF one.
It seems I'm now measuring new transfer functions (which look quite different from what I've got with no amplifiers).
To be posted soon.
Attachment 1: alberto.spectrum2.png
alberto.spectrum2.png
Attachment 2: Butterworth.PNG
Butterworth.PNG
  173   Thu Dec 6 15:21:59 2007 albertoFrogsElectronicsRF Transfer Function of Stiff Aluminum Wires
Transfer function of 3cm long Aluminum wires and of 3cm stranded wires
Attachment 1: TF_3cm_stiff_wires.amplitude.png
TF_3cm_stiff_wires.amplitude.png
Attachment 2: DSC_0225compressed.JPG
DSC_0225compressed.JPG
Attachment 3: TF_3cm_stranded_wires.amplitude.png
TF_3cm_stranded_wires.amplitude.png
  174   Thu Dec 6 15:22:42 2007 AndreySummaryElectronicsPictures of the inside of He-Ne laser

Steve gave me an old "dead" He-Ne laser that long time ago was used for ETMX optical lever.

I dismantled it (cutting the metallic enclosure with a metallic saw), and these are two pictures of what is inside.
Attachment 1: DSC_0226.JPG
DSC_0226.JPG
Attachment 2: DSC_0228.JPG
DSC_0228.JPG
  188   Wed Dec 12 16:22:22 2007 albertoOmnistructureElectronicsLC filter for the RF-AM monitor circuit
In the LC configuration (see attached schematic) the resonant frequency is tuned to one of the peak of our RF-AM monitor and it is amplified by a factor equal to the Q of the filter. As I wrote in one of the last elog entries, we would like amplifications of about 10-30 dB in order to have negligible couplings. Such values are obtained only with small capacitances (few or less pF). The drawback is relatively large inductance (uH or more) which has inevitably low Self Resonant Frequencies (SRF - the resonant frequencies of the RLC circuit usually associated with an actual inductor - ~ MHz). Even before, one limit is also the input impedance of the RF amplifier. Quality factors > 1 require megaohms, far from the 50 ohms in the MiniCircuit amplifiers Iím using now. So, if we plan to use these even for the final design of the circuit, we have to abandon the LC configuration.
For this same reason the only way I could get the expected responses from my several test boards was with a 10 megaohm input probe (see attachment for the measurement with and without probe). Assuming that impedance, I found these as the best trade-offs between the attenuation requirements and the values of the inductors for respectively the peaks at 33, 66,133, 166,199 MHz:
26uH, 6.6u, 20u, 73u, 16u
If we could find inductor with these values and high SRF the configuration should work. The problem is I couldnít find any. Above a few uH they all seem to have SRF ~ MHz.
That is why I switched to the Butterworth. This should work despite the input impedance of the amplifier and with much smaller inductances. I made a totally new test circuit, with surface mount components. I think I still have to fix some things in the measurements but (this time I got rid of the simulator I was using earlier and designed a new configuration with new values from the Horowitzís tables) it seems I have the expected peaks. More soon.
Attachment 1: TF_LC_filter_10pF_1.8uH_scope_probe.png
TF_LC_filter_10pF_1.8uH_scope_probe.png
Attachment 2: TF_LC_filter_10pF_1.8mH_no_probe.png
TF_LC_filter_10pF_1.8mH_no_probe.png
Attachment 3: LC_filter_schematic.png
LC_filter_schematic.png
  190   Thu Dec 13 12:05:36 2007 albertoOmnistructureElectronicsThe new Butterworth seems to work quite well
It works better probably because of the small inductors I'm using this time.
The peak is at 30 MHz because I didn't have the precise elements to get 33.

The bandwidth and the Q could be improved by adding one or two more order to the filter and trying to better match the low-pass' resonant frequency with the high-pass'.

Also I have to see if it could work at 166 and 199 MHz as well.
Attachment 1: TF_New_Butterworth_12-Nov-2007_TF.png
TF_New_Butterworth_12-Nov-2007_TF.png
Attachment 2: Bultervverth2.png
Bultervverth2.png
  193   Mon Dec 17 11:47:13 2007 albertoUpdateElectronicsan alternative design for the RFAM monitor's filter at 33Mhz
Since the Butterworth turned out o be rather wide-band, I tried an other configuration for the 33 MHz filter. Attached are the simulated transfer function and the measured. As one can see, the measured peak is much broader than expected.
Attachment 1: RFSim99-33MHz.png
RFSim99-33MHz.png
Attachment 2: RF99-SimmButterworthPrototype.png
RF99-SimmButterworthPrototype.png
Attachment 3: RFSim99-33MHz-TFplot.png
RFSim99-33MHz-TFplot.png
  246   Thu Jan 17 18:22:14 2008 AlbertoUpdateElectronicsRF Monitor Band-pass Filter
After we finalized the schematic for the RF monitor board based on buffered LC resonators, on Richard Abbott's suggestion to avoid the complication brought in by the fast op-amps, we gave another chance to the a passive configuration of the band-pass filter based on a Chebyshev topology. Rich and Ben gave me an old but very powerful software tool to design that kind of filters and showed me the way to circumvent many hassles in making RF test boards.

I made a test circuit for the 166MHz line (see attached schematic), using tunable inductors. The TF are also attached.
We get more than 20 dB of isolation after 33MHz (with a loss of only few dB at the resonance - it could be less), which is enough for all the other frequencies (33,133,199 MHz) but we would like more for the 166. We are going to add one or two extra orders to the filter.

We also have to understand the spike at about 320Mhz and eventually somehow get rid of it.


Alberto
Attachment 1: RF166Mhz.png
RF166Mhz.png
Attachment 2: Chebyshevb.png
Chebyshevb.png
Attachment 3: Chebyshev2b.png
Chebyshev2b.png
  248   Fri Jan 18 11:53:50 2008 AlbertoUpdateElectronicsRF Monitor Band-pass Filter
The response is asymmetric and on the left side of the peak, we have at least 33dB within 33Mhz, which is enough for all the frequencies. We probably don't need an higher order filter but just low pass filters in series.

The spike at 320MHz doesn't depend on the circuit board. It's either the cables, their connection, or the splitters.

Note that the frequency of this test circuit has still to be tuned exactly at 166MHz (now it's 149).


Alberto



Quote:
After we finalized the schematic for the RF monitor board based on buffered LC resonators, on Richard Abbott's suggestion to avoid the complication brought in by the fast op-amps, we gave another chance to the a passive configuration of the band-pass filter based on a Chebyshev topology. Rich and Ben gave me an old but very powerful software tool to design that kind of filters and showed me the way to circumvent many hassles in making RF test boards.

I made a test circuit for the 166MHz line (see attached schematic), using tunable inductors. The TF are also attached.
We get more than 20 dB of isolation after 33MHz (with a loss of only few dB at the resonance - it could be less), which is enough for all the other frequencies (33,133,199 MHz) but we would like more for the 166. We are going to add one or two extra orders to the filter.

We also have to understand the spike at about 320Mhz and eventually somehow get rid of it.


Alberto
Attachment 1: Chebyshevb.png
Chebyshevb.png
  268   Fri Jan 25 15:53:59 2008 AlbertoUpdateElectronics40 dB from the 3rd order Chebyschev
I managed to tune the 7 knobs in the 3rd order Chebyshev bandpass filter obtaining the tranfer function attached to this entry. We have now 40 dB of attenuation between 166 Mhz and 133 and 199. With this tuning the insertion loss is rather high. We need a better one.


Alberto
Attachment 1: 166MhzElog.png
166MhzElog.png
  285   Wed Jan 30 11:49:30 2008 AlbertoSummaryElectronicsRF monitor's filters final schematics and transfer functions
These are the final schematics for the 6th order Chebyshev filters of the RF monitor board. I'm also attaching the TF as I measured. The tuning is probably not optimal, less insertion noise could be achieved.
Attachment 1: 33Melog30Jan08.png
33Melog30Jan08.png
Attachment 2: 133Melog30Jan08.png
133Melog30Jan08.png
Attachment 3: 166Melog30Jan08.png
166Melog30Jan08.png
Attachment 4: 199Melog30Jan08.png
199Melog30Jan08.png
Attachment 5: 33elog30Jan08.png
33elog30Jan08.png
Attachment 6: 133elog30Jan08.png
133elog30Jan08.png
Attachment 7: 166elog30Jan08.png
166elog30Jan08.png
Attachment 8: 199elog30Jan08.png
199elog30Jan08.png
  314   Wed Feb 13 11:41:00 2008 AlbertoUpdateElectronicsSome characterization of the RF Monitor Box (StocMon)
I'm attaching a table with some measurements and the power spectrum from the pd to help evaluate the numbers.

The box output ranges from 0.5V to 2.1V. The coefficient between power and voltage is negative so higher voltage means lower power.

The red numbers are the outputs from each channel at their resonant frequencies. As one can see these are not very well centered on the dynamic range of the power detectors.

The cross coupling seems to be not a problem.

Even if the 166 filter, which handles the smallest of the frequencies and is also the most lossy (for construction reason), mounts a preamplifier, the output is still rather small. this explain also the high bias due to the noise amplification at the maximum power (13dB). A better insertion loss either remaking the filter or re-tuning that one would simplify many problems, i.e. there is not much room in the metal pomona box to fit the amplifier. I might want to consider, after everything else is ready and if I have time before leaving next week, to work on a new 166 filter.
Attachment 1: CircuitCharacterization.png
CircuitCharacterization.png
Attachment 2: alberto.spectrum3.png
alberto.spectrum3.png
  321   Mon Feb 18 12:04:39 2008 AlbertoUpdateElectronicsRF Monitor (StocMon)
I put the amplifiers next to the monitor on the PSL table, layed the power and the RF SMA cables out to the rack. I'm powering the box and the amplifiers with the power supply, waiting for someone to show me tomorrow how to connect it to the Sorensen (Steve, Ben?).

I'm ready to hook up the channels into EPICS.
Attachment 1: DSC_0443.JPG
DSC_0443.JPG
  329   Thu Feb 21 19:55:46 2008 ranaUpdateElectronics2 BNC Cables, 1 Tee
I'm not sure where Ward and Miller went to Analyzer school, but it was probably uncredited.
I turned it on and used 2 BNC cables and a T to hook up the source to the 2 inputs and measured the always-exciting TF of cable.

Score:  HP Analyzer  1
        Rob & John   0


I have left the analyzer on in this complicated configuration. RTFM boys.


Quote:
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
  331   Fri Feb 22 08:29:07 2008 AlbertoUpdateElectronicsRF Monitor (StocMon)

Quote:
I put the amplifiers next to the monitor on the PSL table, layed the power and the RF SMA cables out to the rack. I'm powering the box and the amplifiers with the power supply, waiting for someone to show me tomorrow how to connect it to the Sorensen (Steve, Ben?).

I'm ready to hook up the channels into EPICS.


Me and Ben Abbot were plugging the cables that power that RF Monitor box into the PSL rack when inadvertently we made some arcs spark between the pins on the back of one of the ADC. Somehow that made the laser shut down although the MOPA stayed on. We also notice some smell of burn.

Later on, after several failed attempts, Rob, Ben and Steve could restart the laser. It took some times because the written procedure to start the chiller is not very precise.
  332   Fri Feb 22 08:33:18 2008 AlbertoUpdateElectronicsRF Monitor (StocMon)

Quote:
I put the amplifiers next to the monitor on the PSL table, layed the power and the RF SMA cables out to the rack. I'm powering the box and the amplifiers with the power supply, waiting for someone to show me tomorrow how to connect it to the Sorensen (Steve, Ben?).

I'm ready to hook up the channels into EPICS.


With Ben, we hooked up the RF Monitor box into the PSL rack and created 4 EPICS channels for the outputs:

C1:IOO_RF_STOC_MON_33
C1:IOO_RF_STOC_MON_133
C1:IOO_RF_STOC_MON_166
C1:IOO_RF_STOC_MON_199

The power cable bringing +15V to the preamplifier on the PSL table should be replaced eventually.
  333   Fri Feb 22 11:11:00 2008 robUpdateElectronicsREFLDD problem found

I used a network analyzer that actually works to find a problem in the REFLDD electronics chain. There was loose (=bad) SMA-BNC adaptor on the output of channel one of the HP RF Amplifier. It worked intermittently, so going onto the ISCT and fiddling with cables could sometimes temporarily fix the problem. The bad adaptor has been given to Andrey to discard.
  334   Fri Feb 22 11:13:15 2008 robUpdateElectronicsRF Monitor (StocMon)

Quote:
It took some times because the written procedure to start the chiller is not very precise.


It is actually very precise. Precisely wrong.
  337   Fri Feb 22 16:47:54 2008 robUpdateElectronicsBaloney
Well I guess Rana didn't study too hard at Professor School, either. If he'd even bothered to actually read John's entry, he might have looked at the RF Out from the HP Analyzer. As it is, this experience so far has been like taking your car to a highly respected mechanic, telling him it's having acceleration problems, and then he takes a rag and wipes some dirt off the hood and then tells you "It's running fine. That'll be 500 bucks."

I make the current score:

Snarkiness: 2
Education:  0



I did RTFM, and it doesn't mention anything about crazy behaviour on the RF Output. So, I set up the analyzer to do a sweep from 500MHz to 1MHz, with output power of 0dBm, and plugged the output directly into the 300MHz scope with the input set to 50 Ohm impedance. The swept sine output looks totally normal from 500Mhz to 150MHz (measuring ~220mVrms below 300MHz -- 0dBm), where it abruptly transitions to a distorted waveform which the scope measures as having a frequency of ~25MHz and with 450mVrms (+6dBm). It then transitions again at some other part of the sweep to a cleaner-looking 25MHz waveform with ~1.2Vrms (+15dBm). See the attached Quicktime movie. The screeching in the background is the PSL door.

With this bizarre behaviour, it's actually possible that even someone who does everything carefully and correctly could break sensitive electronics with this machine. Let's get it fixed or get a new one.

Don't use the HP4195A anymore unless you want broken electronics.


Quote:
I'm not sure where Ward and Miller went to Analyzer school, but it was probably uncredited.
I turned it on and used 2 BNC cables and a T to hook up the source to the 2 inputs and measured the always-exciting TF of cable.

Score:  HP Analyzer  1
        Rob & John   0


I have left the analyzer on in this complicated configuration. RTFM boys.


Quote:
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
Attachment 1: bustedHP.mov
  347   Thu Feb 28 19:49:21 2008 robUpdateElectronicsRF Monitor (StocMon)


Quote:

With Ben, we hooked up the RF Monitor box into the PSL rack and created 4 EPICS channels for the outputs:

C1:IOO_RF_STOC_MON_33
C1:IOO_RF_STOC_MON_133
C1:IOO_RF_STOC_MON_166
C1:IOO_RF_STOC_MON_199

The power cable bringing +15V to the preamplifier on the PSL table should be replaced eventually.


I changed the names of these channels to the more appropriate (and informative, as they're coming from the RFAMPD):

C1:IOO-RFAMPD_33MHZ
C1:IOO-RFAMPD_133MHZ
C1:IOO-RFAMPD_166MHZ
C1:IOO-RFAMPD_199MHZ

I also added them in an aesthetically sound manner to the C1IOO_LockMC.adl screen and put them in trends. Along the way, I also lost whatever Alberto had done to make these monitors read zero when there's no light on the diode. It doesn't appear to be written down anywhere, and would have been lost with a reboot anyway. We'll need a more permanent & automatable solution for this.
  397   Sun Mar 23 10:42:54 2008 ValeraSummaryElectronicsRFAM of the RF stabilization box is measured
I reconstructed Tobin's setup to measure the RFAM after the RF stabilization box in the 166 MHz modulation path.
The setup consisted of the splitter and the mixer followed by the RF low pass filter and the SR560 (gain x100).
The RF level into splitter was 20 dBm. The Mini-Circuits ZLW-3H (17 dBm LO) mixer was used. The LO was taken
straight out of the splitter and the RF path was attenuated by 11 dBm, The DC out of the mixer was 700 mV.
The noise floor was measured with the RF input of the mixer terminated on 50 Ohm. The 45 MHz measurement
in broad band setting looks better than the noise floor at high frequencies. I am not sure what was wrong with
one or both of those measurements. The 9 MHz measurements are above the noise floor.

The RFAM meets the AdvLIGO requirements in the detection band (f > 10 Hz).

The attached zipped files are:
SRS003 9 MHz DC-200 Hz
SRS004 9 MHz DC-26 kHz
SRS006 45 MHz DC-200 Hz
SRS005 45 MHz DC-26 kHz
SRS007 Noise floor DC-200 Hz
SRS008 Noise floor DC-26 kHz
Attachment 1: RFAM.zip
Attachment 2: amplitudenoise.pdf
amplitudenoise.pdf
  398   Mon Mar 24 13:03:54 2008 robUpdateElectronicsHP4195A is back



Quote:
The swept sine output looks totally normal from 500Mhz to 150MHz (measuring ~220mVrms below 300MHz -- 0dBm), where it abruptly transitions to a distorted waveform which the scope measures as having a frequency of ~25MHz and with 450mVrms (+6dBm). It then transitions again at some other part of the sweep to a cleaner-looking 25MHz waveform with ~1.2Vrms (+15dBm).


The HP4195A is back from repair. At first, it exhibited exactly the same behaviour for which it was sent in for repair, and which is described above (pillage from entry 337). After speaking with the repair tech on the phone, who tried to imply that the digital scope was tricking us, I plugged the output into our HP8591E spectrum analyzer, just to have firm ammunition to combat the repair guy's looniness. This led to even weirder behaviour, like no output and overload signals on the inputs (with nothing connected). After turning the unit on and off several times, and firmly seating (and screwing in) the DB9 connectors in the back of the unit, it appears to be working properly. Except for a brief glitch as it passes through 150MHz, the swept sine signal now appears normal, both on the scope and in the spectrum analyzer.

Apparently the whole thing is due to a loose connection somewhere in the box, which wasn't actually fixed by the repair, but has at least been temporarily fixed by me stumbling around with a screwdriver and then pushing the power button a couple of times.
  580   Thu Jun 26 22:08:33 2008 JenneUpdateElectronics3.7MHz bandstop filter in MC Servo
The 3.7MHz elliptical bandstop filter that I made during my SURF summer is now installed in the MC servo loop to reduce the noise at 3.7MHz.

I have taken transfer functions with and without the filter between TP1A and TP2A, with EXCA at -20dBm, using the HP4195A Network Analyzer. I have also taken power spectra of TP1A with and without the filter, and time domain data with the filter of OUT2 on the MC Servo Board and Qmon on the Demod board just before the MC servo board. The filter is between Qmon and OUT2 in the loop.

The UGF and phase margin don't change noticeably with and without the filter, and the MC still locks nicely (after the minor fiasco this afternoon), so I think it's okay. The UGF is around 57kHz, with about 38 degrees phase margin.

1 July 2008: I redid the plots. Same info, but the traces with and without the filters are now on the same graph for easier readability.
Attachment 1: MCLoopGainBoth.png
MCLoopGainBoth.png
Attachment 2: TP1ASpectrumBoth.png
TP1ASpectrumBoth.png
Attachment 3: QmonWithFilt.png
QmonWithFilt.png
Attachment 4: MCOut2WithFilt.png
MCOut2WithFilt.png
  584   Fri Jun 27 18:03:46 2008 JenneUpdateElectronicsAnother bad cable in the MC servo
Eric was helping me to measure the response of the LO input on the MC's Demod board, and when we disconnected the end of the cable between the demod board and the delay line phase shifter for the 29.5MHz oscillator, we noticed that the phase shifter's end of the cable was loose, like the connector wasn't fully connected. When we checked it by wiggling the connector, the SMA end fell off. I made a new SMA end for the cable, and reinstalled the cable. The MC locked as soon as I plugged the cable in, so everything seems good again. I tried to not change the cable length when I remade the connector, but the cable is shorter than it was by a small amount, due to the way the end fell off.
  585   Fri Jun 27 18:21:01 2008 JenneUpdateElectronicsResponse of the LO input on the MC demod board
The alarm handler has been flipping out saying that the LO input of the MC's demod board is too low, so at Rana's suggestion, Eric and I measured the response of the LO input. We used an SR345 function generator at 29.485MHz and several different amplitudes to make a table. The demod board should see an input from the LO between 0-2dBm. When I measured what was going into the LO input from the 29.5MHz delay line phase shifter, the LO input was seeing 4dBm. I'm going to put a 3dB attenuator between the phase shifter and the demod board.

Also, now that we have this table of response values, I'm going to change the settings of the alarm handler to something more reasonable.
Amplitude of 29.485MHz input sine wave [dBm]    |        Value of channel C1:IOO-MC_DEMOD_LO
--------------------------------------------    |        -----------------------------------
-10                                             |        -0.000449867
-8                                              |        -0.000449867
-6                                              |        -0.000449867
-4                                              |        0.000384331
-2                                              |        0.00526733
0                                               |        0.0199163
2                                               |        0.0492143
4                                               |        0.0931613
6                                               |        0.161523
8                                               |        0.229885
10                                              |        0.293364
  605   Mon Jun 30 15:56:22 2008 JenneUpdateElectronicsFixing the LO demod signal
To make the alarm handler happy, at Rana and John's suggestion I replaced R14 of the MC's Demod board, changing it from 4.99 Ohms to 4.99 kOhms. This increased the gain of the LO portion of the demod board by a factor of 10. Sharon and I have remeasured the table of LO input to the demod board, and the output on the C1:IOO-MC_DEMOD_LO channel:

Input Amplitude to LO input on demod board [dBm]: | Value of channel C1:IOO-MC_DEMOD_LO
------------------------------------------------- | -----------------------------------
-10 | -0.00449867
-8 | 0.000384331
-6 | 0.0101503
-4 | 0.0296823
-2 | 0.0882783
0 | 0.2543
2 | 0.542397
4 | 0.962335
6 | 1.65572
8 | 2.34911
10 | 2.96925
  888   Tue Aug 26 18:19:16 2008 ranaOmnistructureElectronicsResistor Noise at the 40m
As Stefan points out in his recent ISS ilog entries at LLO, Daniel Sigg recently wrote a
recommendation memo on resistor and capacitor
choices: T070016.

While working on the PMC I have had to use leaded resistors and wondered about the noise. As it turns
out we have the RN series of 1/4 W resistors from Stackpole Electronics. The RN series are
metal film resistors (datasheet attached); metal film is what Sigg recommends for lowest flicker
noise.

So we are OK for using the Stackpole 1/4 W leaded resistors in low noise circuits.
Attachment 1: SEI-RN_RNM.pdf
SEI-RN_RNM.pdf SEI-RN_RNM.pdf
  915   Wed Sep 3 18:43:19 2008 YoichiConfigurationElectronicsTwo more active probes
I found two active probes, an HP41800A and a Tektronix P6201.
Thanks John for telling me you saw them before.
Now we have three active probes, wow !
We have to find or make a power supply for P6201.
The manual of the probe is attached.
Attachment 1: Tektronix-P6201-active-probe.pdf
Tektronix-P6201-active-probe.pdf Tektronix-P6201-active-probe.pdf Tektronix-P6201-active-probe.pdf Tektronix-P6201-active-probe.pdf Tektronix-P6201-active-probe.pdf Tektronix-P6201-active-probe.pdf Tektronix-P6201-active-probe.pdf Tektronix-P6201-active-probe.pdf
  939   Wed Sep 10 13:28:25 2008 YoichiSummaryElectronicsIOO rack lost -24V (recovered)
Alberto, Yoichi

This morning, the MC suddenly started to be unwilling to lock.
I found a large offset in the MC servo board.
It turned out that -24V was not supplied to the Eurocard crate of the IOO rack.
We found two loose cables (violet, that means -24V) around the cross connects with fuses.
We connected them back, and the -24V was back.
The MC locks fine now, and Alberto can continue his arm length experiment.
  1036   Wed Oct 8 22:23:43 2008 YoichiConfigurationElectronicsElectronics work bench cleanup
Yesterday, I cleaned up the electronics work bench. I figured that keeping the work bench
in order has larger effect on the work efficiency than buying expensive soldering stations.
Whoever works there should clean up the table after the work to the state shown on
the right side of the picture (at least).
If you leave the bench for a while (more than 30min) but intend to return later and
resume the work, please write your name and time on a piece of paper and put it on the bench.
Otherwise, your stuff can be taken away anytime.
Attachment 1: Cleanup.jpg
Cleanup.jpg
  1135   Fri Nov 14 17:41:50 2008 JenneOmnistructureElectronicsSweet New Soldering Iron
The fancy new Weller Soldering Iron is now hooked up on the electronics bench.

Accessories for it are in the blue twirly cabinet (spare tips of different types, CD, and USB cable to connect it to a computer, should we ever decide to do so.

Rana: the soldering iron has a USB port?
Attachment 1: newSolderingIron.JPG
newSolderingIron.JPG
  1139   Mon Nov 17 11:01:15 2008 AlbertoHowToElectronicsCalibrating the Frequency Standard of the Marconi
I locked the SRS Rubidium Frequency Standard FS275 to the the 1pps from the GPS. The specs from the manual provide a frequency accuracy of 5x10^-11, that is 5x10-4 @ 10 MHz, since this is the reference signal frequency we're are going to use.
The Marconi internal frequency standard is provided by a TCXO oscillator. The instrument can be set in either one of these ways: 1) Indirect Synchronization, by which the internal TCXO is phase-locked to the external frequency standard (i.e. the SRS FS275 in our case) 2) Direct Sync, in which the internal TCXO is bypassed and the frequency standard is the external one.

I checked the specs of both frequency standards and found:

SRS FS275: 5x10^-11 -> 5x10^-10 Hz @ 10 MHz

Marconi: here what the data sheet says is that "the temperature coefficient is 7 in 10^7 in the temperature range between 0 and 55 C" and so should be also the frequency accuracy.

The SRS FS275 seems more accurate than the TCXO therefore I'm going to set the Marconi on the direct external mode.
Attachment 1: 2023ASeriesOperatingManual.pdf
2023ASeriesOperatingManual.pdf 2023ASeriesOperatingManual.pdf 2023ASeriesOperatingManual.pdf 2023ASeriesOperatingManual.pdf
Attachment 2: SRS_FS275_Rubidium_Frequency_Standard.pdf
SRS_FS275_Rubidium_Frequency_Standard.pdf SRS_FS275_Rubidium_Frequency_Standard.pdf
  1146   Wed Nov 19 10:32:11 2008 AlbertoConfigurationElectronicsAll the Marconi Set to the Rubidium Frequency Standard
I placed the SRS Rubidium FS275 over the PSL rack, next to the frequency counter. This one and the Marconi on the PSL rack have been connected to the 10MHz output of the frequency standard. I set also the first Marconi, the one that used to drive the others, to external, direct frequency reference. Now it reads 166981718 Hz versus 166981725 Hz measured by the frequency counter: 8 Hz difference.
  1147   Wed Nov 19 18:02:18 2008 ranaConfigurationElectronicsAll the Marconi Set to the Rubidium Frequency Standard
Not sure what was going on before. I changed the frequency counter to use an AC coupled input, and had it average
for 50 seconds. The output now agrees with the Marconi front panel to less than 1 Hz. Its still not 0.000 Hz,
but not bad.
  1208   Tue Dec 30 18:51:18 2008 rana,yoichiConfigurationElectronicsIlluminator Power Supply reset
We noticed that none of the illuminators were working.

The switches were off on all the ports. After turning them on it still didn't work.

The +24 V Sorensen power supply which powers all of the illuminators had its OVP light on.
We turned it off, ramped the voltage to zero, turned it back on, and then went back to +24 V.

We then checked the operation of the illuminators; ETMY is still MIA.

Each of the illuminators sucks ~0.6-0.7 A when the (unlabeled) rheostat knob panel is set
to the "25" setting.

It seems pretty unwise, in the EMI sense, to be sending Amps of unshielded, high current,
switching supply outputs for 40m down the arms. This creates a huge antenna for radiating
the switching noise. I hereby assign minus 5 points to whoever designed this system.

Illuminator Upgrade:
- Use LEDs of a wavelength that the OSEMs don't see. LEDs are also cool so that the
  Suspension won't drift in alignment.

- Use 2 power supplies so that the power is balanced.

- Make is +/-12 V twisted AWG 14 wire so that the EMI is contained. Should also
  be shielded cable.
  1252   Sat Jan 24 11:50:24 2009 AlbertoConfigurationElectronicsPhotodiode Filters' Transfer Functions
I found an elog entry by Jenne with the measurement of the transfer functions of the filters of some of our photodetectors. Since it might turn useful to us these days, while I'm thinking about posting them on the wiki sometime, I also copy the link here:
Jenne's on the PD's TF

If we still had the data for those plots, it would be great. Do we have it?
  1315   Mon Feb 16 23:09:52 2009 ranaUpdateElectronicsMC Servo Board offset gone bad!

The attached plot shows that someone broke the MC_SUM_MON channel around 10:30 AM this past Wednesday the 11th. This is the EPICS monitor of the MC error point.

Come forward now with your confession and I promise that I won't let Steve hurt you.

Attachment 1: mcoff.png
mcoff.png
  1326   Thu Feb 19 22:40:33 2009 KiwamuUpdateElectronicsPSL angle QPD

I checked a broken QPD, which was placed for PSL angle monitor, and finally I cocluded one segment of the quadrant diode was broken.

The broken segment has a offset voltage of -0.7V after 1st I-V amplifier. It means the diode segment has a current offset without any injection of light.

Tomorrow I will check a new QPD for replacement.

Kiwamu IZUMI

 

  1345   Mon Mar 2 16:27:40 2009 AlbertoConfigurationElectronicsMC Drum Mode SR560 Preamplifier Replaced

Today I checked out the SR560 around the lab. I confirmed that the one with the label "channel A noisy" is effectively mulfuctioning.

It was coonected to the lock-in amplifier set up for the drum mode peak readout.

I repleaced that with a working one.

  1407   Mon Mar 16 15:19:52 2009 OsamuDAQElectronicsSR785

I borrowed SR785 to measure AA, AI noise and TF.

  1445   Mon Mar 30 15:51:27 2009 steveUpdateElectronicsHP4291A left the lab to be repaired

Eric Gustafson is handling the old HP4291A rehabilitation. Tarac picked both units up today.

March of 2008 Tucker Electronics failed to fix it's intermittent ~25MHz 0.5V oscillation at the swept sine output

See 40m-elog id:398 on 3-24-2008 by Rob Ward

 

  1476   Sun Apr 12 19:31:43 2009 ranaSummaryElectronicsAmphony 2500 Headphones
We bought the Amphony 2500 Digital Wireless headphones recently. The other cheapo headphones we have are OK for control room use, but have a lot of noise
and are, therefore, not useful for noise hunting.

The new digital ones are pretty much noise-free. With the transmitter next to rosalba, you can walk halfway down the east arm and all around the MC area
before the reception goes bad. For real noise hunting, we will want to put the transmitter next to the BS chamber and take an analog pickoff from the DC PDs.

In the OMC diagram, we should put an AUDIO filterbank and wire it to the DAC so that we can do arbitrary IIR filtering on the audio signal.
ELOG V3.1.3-