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ID Date Author Type Category Subjectup
  2610   Wed Feb 17 12:45:19 2010 josephbUpdateComputersUpdated Megatron and its firewall

I updated the IP address on the Cisco Linksys wireless N router, which we're using to keep megatron separated from the rest of the network.  I then went in and updated megatrons resolv.conf and host files.  It is now possible to ssh into megatron again from the control machines.

  2392   Thu Dec 10 18:27:48 2009 MottUpdateGeneralUpdated R & T Measurements

Attached are updated plots of the T&R Measurements for a variety of mirrors, and diagrams for the setup used to make the measurements.

T is plotted for the 1064 nm measurement, since these mirrors are highly reflective at 1064, and either R or R&T are plotted for the 532 nm measurement, depending on how larger the R signal is.

As with the previous set of plots, the error bars here are purely statistical, and there are certainly other sources of error not accounted for in these plots.  In general, the T measurement was quite stable, and the additional errors
are probably not enormous, perhaps a few percent.

The mirrors are:

Y1-1037-00.50CC

Y1-2037-45S

Y1-2037-45P

Y1S-1025-0

Y1S-1025-45

 

Attachment 1: Y1S-0.png
Y1S-0.png
Attachment 2: Y1S-45.png
Y1S-45.png
Attachment 3: Y45P.png
Y45P.png
Attachment 4: Y45S.png
Y45S.png
Attachment 5: Y150CC.png
Y150CC.png
Attachment 6: Setup.png
Setup.png
  3612   Mon Sep 27 17:35:13 2010 josephbUpdateCDSUpdated Suspension screens/Megatron now c1ioo/Further work on fb

The medm screens have been updated further, with the hidden matrices added in bright colors.  An example screen shot is attached.

Megatron has been renamed c1ioo and moved to martian network.  Similarly, c1sus and c1iscex are also on the martian network.  Medm screens can be run on any of the control machines and they will work.

Currently the suspension controller is running on c1sus.

The frame builder is currently running on the fb machine *however* it is not working well.  Test points and daq channels on the new front ends tended to crash it when Alex started the mx_stream to the fb via our new DAQ network (192.168.114.XXX, accessible through the front ends or fb - has a dedicated 1 gigabit network with up to 10 gigabit for the fb).  So for the moment, we're running without front end data. Alex will be back tomorrow to work on it. 

Alex claimed to have left the frame builder in a state where it should be recording slow data, however, I can't seem to access recent trends (i.e. since we started it today).  The frame builder throws up an error "Couldn't open raw minute trend file '/frames/trend/minute_raw/C1:Vac-P1_pressure', for example.  Realtime seems to work for slow channels however.  Remember to connect to fb, not fb40m. So it seems the fb is still in a mostly non-functional state.

Alex also started a job to convert all the old trends to the correct new data format, which should finish by tomorrow.

RA: Nice screen work. The old screens had a 'slow' slider effect when ramping the bias so that we couldn't whack the optic too hard. Is the new one instantaneous?

Attachment 1: MC1_Example_Screen.png
MC1_Example_Screen.png
  3615   Tue Sep 28 10:07:29 2010 josephbUpdateCDSUpdated Suspension screens/Megatron now c1ioo/Further work on fb

Quote:

RA: Nice screen work. The old screens had a 'slow' slider effect when ramping the bias so that we couldn't whack the optic too hard. Is the new one instantaneous?

 Looking at the sliders, I apparently still need to connect them properly.  There's a mismatch between the medm screen channel name and the model name.  At the moment there is no "slow" slider effect implemented, so they are effectively instantaneous.  Talking with Alex, he suggests writing a little c-code block and adding it to the model.  I can use the c code used in the filter module ramps as a starting point.

  13004   Mon May 22 15:01:41 2017 jigyasaUpdatetelescope designUpdated Telescope design with 1'' eye piece

I examined the use of a single lens system for the available range of focal lengths, for the required magnification and found that a focal length of at most 100 mm would be required to sufficiently cover the object distance range. This would greatly compromise with the f-number and hence lead to a lot more spherical aberrations.

Therefore, a two lens system would be more useful to implement. Using an eyepiece of 1” puts an additional constraint on the system such that the separation between the lenses must now at least equal or be greater than half the image distance from the first lens to ensure that no light from the light cone is lost. This is clarified in the schematic. The image from the first lens in absence of the second lens would form at point A, subtending an angle θ. In order to ensure that no part this light cone emerging from the first lens is lost, the second lens must be placed at a distance atleast v/2 from the first lens.

A combination of 125mm focal length 2” diameter objective with a 250 mm 1” eyepiece covers the required range of object distances (650mm to 1500 mm). Increasing the focal length of the eye piece increases the minimum object distance accessible to 700 mm. 

A glance at the accessible u, v points shows that all magnifications are not possible at a given object distance. To image the entire surface of the test mass, a distance of at least 1.25m is required from the objective, while a beam spot of 1'' diameter can be imaged easily at upto 1200 mm from the objective . This holds true even for the 150-250 mm biconvex 2" lens combination proposed earlier. 

If this sounds reasonable, we could proceed with ordering the lenses.

Attachment 1: 1incep.pdf
1incep.pdf
  11395   Wed Jul 8 17:46:20 2015 JessicaSummaryGeneralUpdated Time Delay Plots

I re-measured the transfer function for Cable B, because the residuals in my previous post for cable B indicated a bad fit. 

I also realized I had made a mistake in calculating the time delay, and calculated more reasonable time delays today. 

Cable A had a delay of 202.43 +- 0.01 ns.

Cable B had a delay of 202.44 +- 0.01 ns. 

Attachment 1: resid_CableA.png
resid_CableA.png
Attachment 2: resid_CableB.png
resid_CableB.png
  3978   Tue Nov 23 16:55:14 2010 josephbUpdateCDSUpdated apps

Updated Apps:

I created a new setup script for the newest build of the gds tools (DTT, foton, etc), located in /opt/apps (which is a soft link from /cvs/cds/apps) called gds-env.csh.

This script is now sourced by cshrc.40m for linux 64 bit machines.  In addition, the control room machines have a soft link in the /opt directory to the /cvs/cds/apps directory.

So now when you type dtt or foton, it will bring up the Centos compiled code Alex copied over from Hanford last month.

  3983   Tue Nov 23 23:52:49 2010 ranaUpdateCDSUpdated apps

Wow. I typed DTT on rossa and it actually worked! No complaints about testpoints, etc. I was also able to use its new 'NDS2' function to get data off of the CIT cluster (L1:DARM_ERR from February). You have to use the kinit/kdestroy stuff to use NDS2 as usual (look up NDS2 in DASWG if you don't know what I mean).

  2844   Mon Apr 26 11:29:37 2010 josephbUpdateComputersUpdated bitwise.pm in RCG SVN plus other fixes

To fix a problem one of the models was having, I checked the CVS version of the Bitwise.pm file into the SVN (located in /home/controls/cds/advLigoRTS/src/epics/util/lib), which adds left and right bit shifting funtionality.  The yec model now builds with the SVN checkout.

Also while trying to get things to work, I discovered the cdsRfmIO piece (used to read and write to the RFM card) now only accepts 8 bit offsets.  This means we're going to have to change virtually all of the RFM memory locations for the various channels, rather than using the values from its previous incarnation, since most were 4 bit numbers.  It also means it going to eat up roughly twice as much space, as far as I can tell.

Turns out the problem we were having getting to compile was nicely answered by Koji's elog post.  The shmem_daq value was not set to be equal to 1.  This caused it to look for myrimnet header files which did not exist, and caused compile time errors.  The model now compiles on megatron.

[Edit by KA: 4 bit and 8 bit would mean "bytes". I don't recall which e-log of mine Joe is referring.]

 

  16037   Thu Apr 15 17:24:08 2021 JonUpdateCDSUpdated c1auxey wiring plan

I've updated the c1auxey wiring plan for compatibility with the new suspension electronics. Specifically it is based on wiring schematics for the new HAM-A coil driver (D1100117), satellite amplifier (D1002818), and HV bias driver (D1900163).

Changes:

  • The PDMon, VMon, CoilEnable, and BiasAdj channels all move from DB37 to various DB9 breakout boards.
  • The DB9 cables (x2) connecting the CoilEnable channels to the coil drivers must be spliced with the dewhitening switching signals from the RTS.
  • As suggested, I added five new BI channels to monitor the state of the CoilEnable switches. For lack of a better name, they follow the naming convention C1:SUS-ETMY_xx_ENABLEMon.

@Yehonathan can proceed with wiring the chassis.

Quote:

I finished prewiring the new c1auxey Acromag chassis (see attached pictures). I connected all grounds to the DIN rail to save some wiring. The power switches and LEDs work as expected.

I configured the DAQ modules using the old windows machine. I configured the gateway to be 192.168.114.1. The host machine still needs to be setup.

Next, the feedthroughs need to be wired and the channels need to be bench tested.

Attachment 1: C1AUXEY_Chassis_Feedthroughs_-_By_Connector.pdf
C1AUXEY_Chassis_Feedthroughs_-_By_Connector.pdf
  16052   Mon Apr 19 21:54:55 2021 YehonathanUpdateCDSUpdated c1auxey wiring plan

Except for the feed-throughs that require a DB9-M connector I finished wiring and labeling the Acromag, following Jon's updated wiring plan.

We can start testing the differential inputs until the missing connectors arrive.

 

  16092   Wed Apr 28 18:56:57 2021 Yehonathan, JonUpdateCDSUpdated c1auxey wiring plan

We took a Supermicro from the lab (along with a keyboard, a mouse, and a screen taken from a table on the Y arm) and placed it near the Acromag chassis.

We installed Debian 10 on the machine. I followed the steps on the slow machine wiki for setting up the host machine. Some steps had to be updated. Most importantly, in the new Debian, the network interfaces are given random names like enp3s0 and enp4s0 instead of eth0 and eth1. I updated the wiki accordingly.

To operate the chassis using one 15V source I disconnected the +24V cable from the Acromag units and jumpered the +15V wire into the power input instead. I started up the Acromags. They draw 0.7A. I connected an Ethernet cable to the front interface. I checked that all the Acromags are connected to the local network of the host machine by pinging them one by one.

 

  16098   Thu Apr 29 16:35:51 2021 YehonathanUpdateCDSUpdated c1auxey wiring plan

I installed the EPICs base, asyn and modbus modules according to Jon's instructions.

Since the modbus configurations files were already writtten for c1auxey1 (see elog 15292) the only thing I did was to change the IP addresses in ETMYaux.cmd to match the actual assigned IPs.

I followed the rest of the instructions as written.

The modbus service was activated succesfully.

The only thing left to do is to change ETMYaux.db to reflect to new channels that were added. I believe these are BI channels named C1:SUS-ETMY_xx_ENABLEMon.

 

  16103   Thu Apr 29 19:55:45 2021 YehonathanUpdateCDSUpdated c1auxey wiring plan

We received a stock of DB9 male feed-through connectors. That allowed me to complete the remaining wiring on the c1auxey Acromag chassis. The only thing left to be done is the splicing to the RTS.

 

  16107   Fri Apr 30 19:18:51 2021 Yehonathan, JonUpdateCDSUpdated c1auxey wiring plan

We finished the installation procedure on the c1auxey1 host machine. There were some adjustments that had to be made for Debian 10. The slow machine wiki page has been updated.

A test database file was made were all the channel names were changed from C1 to C2 in order to not interfere with the existing channels.

We starting testing the channels one by one to check the wiring and the EPICs software. We found some misswirings and fixed them.

Channel Name Type EPICs Test Acromag windows software test
C2:SUS-ETMY_ULPDMon AI Pass Pass
C2:SUS-ETMY_URPDMon AI Pass Pass
C2:SUS-ETMY_LLPDMon AI Pass Pass
C2:SUS-ETMY_SPDMon AI Pass Pass
C2:SUS-ETMY_LRPDMon AI Pass Pass
C2:SUS-ETMY_ULVMon AI Pass Pass
C2:SUS-ETMY_URVMon AI Pass Pass
C2:SUS-ETMY_LLVMon AI Pass Pass
C2:SUS-ETMY_SideVMon AI Pass Pass
C2:SUS-ETMY_LRVMon AI Pass Pass

Its getting late. I'll continue with the rest of the channels on Monday.

Notice that for all the AI channels the RTN was disconnected while testing.

 

 

 

 

 

 

  16114   Mon May 3 20:36:46 2021 Yehonathan, JonUpdateCDSUpdated c1auxey wiring plan

It seemed like the BIO channels were not working, both the inputs and the outputs. The inputs were working on the windows machine though. That is, when we shorted the BIO channel to the return, or put 0V on it, we could see the LED turn on on the I/O testing screen and when we ramped up the voltage above 3 the LED turned off. This is the expected behavior from a sinking digital input. However, the EPICs caget didn't show any change. All the channels were stuck on Disabled.

We checked the digital outputs by connecting the channels to a fluke. Initially, the fluke showed 13V. We tried to toggle the digital output channels with caput and that didn't work. We checked the outputs with the windows software. For that, we needed to stop the Modbus. To our surprise, the windows software was not able to flip the channels either. We realized that this BIO Acromag unit is probably defective. We replaced it with a different unit and put a warning sticker on the defective unit. Now, the digital outputs were working as expected. When we turned them on the voltage output dropped to 0V. We checked the channels with the EPICs software. We realized that these channels were locked with the closed loop definition. We turned on the channels tied to these output channels (watchdog and toggles) and it worked. The output channels can be flipped with the EPICs software. We checked all the digital output channels and fixed some wiring issues along the way.

The digital input channels were still not working. This is a software issue that we will have to deal with later.

(Yehonathan) Rana noticed that the BNC leads on the chassis front panel didn't have isolation on them so I redid them with shrinking tubes.

  4200   Tue Jan 25 15:20:38 2011 josephbUpdateCDSUpdated c1rfm model plus new naming convention for RFM/Dolphin

After sitting down for 5 minutes and thinking about it, I realized the names I had been using for internal RFM communication were pretty bad.  It was because looking at a model didn't let you know where the RFM connection was coming from or going to.  So to correct my previous mistakes, I'm instituting the following naming convention for reflected memory, PCIE reflected memory (dolphin) and shared memory names.  These don't actually get used anywhere but the models, and thus don't show up as channel names anywhere else.  They are replaced by raw hex memory locations in the actual code through the use of the IPC file (/opt/rtcds/caltech/c1/chans/ipc/C1.ipc).  However it will make understanding the models easier for anyone looking at them or modifying them.

 

The new naming convention for RFM and Dolphin channels is as follows.

SITE:Sending Model-Receiving Model_DESCRIPTION_HERE

The description should be unique to that data being transferred and reused if its the same data.  Thus if its transfered to another model, its easy to identify it as the same information.

The model should be the .mdl file name, not the subsystem its a part of.  So SCX is used instead of SUS.  This is to make it easier to track where data is going.

In the unlikely case of multiple models receiving, it should be of the form SITE:Sending Model-Receiving Model 1-Receiving Model 2_DESCRIPTION_HERE.  Seperate models by dashes and description by underscores.

Example:

C1:LSC-RFM_ETMX_LSC

This channel goes from the LSC model (on c1lsc) to the RFM model (on c1sus).  It transfers ETMX LSC position feedback.  The second LSC may seem redundant until we look at the next channel in the chain.

C1:RFM-SCX_ETMX_LSC

This channel goes from the RFM model to the SCX model (on c1iscex). It contains the same information as the first channel, i.e. ETMX LSC position feedback.

 

I have updated all the models that had RFM and SHMEM connections, as well as adding all the LSC communciation connections to c1rfm.  This includes c1sus, c1rfm, c1mcs, c1ioo, c1gcv, c1lsc, c1scx, c1scy.  I have not yet built all the models since I didn't finish the updates until this afternoon.  I will build and test the code tomorrow morning.

 

 

 

  4265   Wed Feb 9 15:26:22 2011 josephbUpdateCDSUpdated c1scx with lockin, c1gcv for green transmission pd

Updated the c1scx model to have two Lockin demodulators (C1:SUS-ETMX_LOCKIN1 and C1:SUS-ETMX_LOCKIN2).  There is a matrix C1:SUS-ETMX_INMUX which directs signals to the inputs of LOCKIN1 and LOCKIN2.  Currently only the GREEN_TRX signal is the only signal going in to this matrix, the other 3 are grounds.  The actual clocks themselves had to be at the top level (they don't work inside blocks) and thus named C1:SCX-ETMX_LOCKIN1_OSC and C1:SCX-ETMX_LOCKIN2_OSC.

 

There is a signal (IPC name is C1:GCV-SCX_GREEN_TRX) going from the c1gcv model to the c1scx model, which will contain the output from Jenne's green transmission PD which will eventually be placed. I've placed a filter bank on it in the c1gcv model as a monitor point, and it corresponds to C1:GCV-GREEN_TRX.

 

The suspension control screens were modified to have a screen for the Matrix feeding signals into the two lockin demodulators.  The green medm screen was also modified to have readbacks for the GREEN_TRX and GREEN_TRY channels.

 

So on the board, the top channel (labeled 1, corresponds to code ADC_0_0) is MCL.

Channel 2 (ADC_0_1) is assigned to frequency divided green signal.

Channel 3 (ADC_0_2) is assigned to the beat PD's DC output.

Channel 4 (ADC_0_3) is assigned to the green power transmission for the x-arm.

Channel 5 (ADC_0_4) is assigned to the green power transmission for the y-arm.

  3715   Thu Oct 14 10:59:10 2010 josephbUpdateComputersUpdated cshrc.40m and Computer Restart Procedures

I started modifying the cshrc.40m file in /cvs/cds/caltech/ so that it starts pointing at the new directories.

# misc aliases
alias target 'cd /opt/rtcds/caltech/c1/target'
alias scripts 'cd /opt/rtcds/caltech/c1/scripts'
alias chans 'cd /opt/rtcds/caltech/c1/chans'
alias c 'cd /opt/rtcds/caltech/c1'
alias s 'cd /opt/rtcds/caltech/c1/scripts'
alias u 'cd /cvs/cds/caltech/users'

I also added "alias screens 'cd /opt/rtcds/caltech/c1/medm'" as a quick way to get to the medm directory.

Once we get multiple compiled versions (i.e. i386, x86_64, Solaris) of the new gds tools from Alex, we'll have to some more serious surgery on this file.

I removed the "New Computer Restart Procedures" and simply moved the changes into the "Computer Restart procedures", found here.  I've removed everything I don't think applies anymore (all the VME FE reboot procedures for example).

  6161   Tue Jan 3 17:46:38 2012 Updated Stewart platform design requirementsUpdateGeneralUpdated design requirements for a Stewart platform

I updated the design requirements for the Stewart platform.  I weighed the unloaded "dirty" SOS that was sitting on the workbench in the control room; its mass is 11 kg.  Steve suggested that the OSEMs (not installed on this model) would add another 0.5 kg.  From the specs in the final SOS design document, LIGO-T970135, I added 0.25 kg for the optic itself; I am therefore taking the total payload mass to be 11.75 kg.  (Now, the upper stage of the Stewart platform itself will likely add a nontrivial amount, but I am not worrying about this yet.)

I have e-mailed Janeen Romie to obtain the actual center of mass and principal moments of inertia of the platform.  I also cooked up a simple scheme to measure both quantities, should this information not be available.  It would involve rigidly mounting the dirty SOS to a rigid bar hung from a pivot.  By translating the mount point in two dimensions and measuring the period of the pendulum, I ought to be able to find the center of mass and moments of inertia by multilinear regression.  However, this elaborate scheme is not necessary to just compute some ballpark figures; it could wait until a later stage in the design.  For the time being, I just rescaled the moment of inertia proportional to the increase in mass, such that the torque-to-force ratio is unchanged.

As such, the design requirements are now 

  • linear travel: 40 microns peak to peak (based on SOS design requirements in LIGO-T950011)
  • angular travel: 3 mrad peak to peak (based on SOS design requirements in LIGO-T950011)
  • payload mass: 11.75 kg (measured unloaded mass, plus educated guesses about combined mass of OSEMs and optic)
  • payload moment of inertia: 0.0232 kg m^2 (wild guess)
  • bandwidth: 500 Hz (suggestion of Rana and Koji: ~kHz)

From these assumptions, the revised actuator requirements and dimensions are:

  • peak actuator force: 2.04 kN
  • minimum radius of top platform: 15 cm
  • minimum radius of bottom platform: 30 cm
  • minimum height: 26 cm

See the attached PDF document.

It appears that the actuator that I had originally nominated, PI's model P-225.80, would very nearly meet the actuator force requirement.  Steve also pointed out the following single-axis shakers that are already in use in the 40m:

  • Brüel & Kjær type 4809
  • Brüel & Kjær type 4810

I want to find out if either of these would meet the present need, but I'm waiting on a response from the manufacturer to get access to the data sheets.

 

Attachment 1: stewart.pdf
stewart.pdf stewart.pdf stewart.pdf stewart.pdf stewart.pdf stewart.pdf stewart.pdf stewart.pdf
  10383   Thu Aug 14 14:58:03 2014 JenneUpdateGeneralUpdated game plan

2014_Aug_14.pdf

(Updated as of 4pm)

  10385   Thu Aug 14 15:42:29 2014 KojiUpdateGeneralUpdated game plan

 - ALS

End PDH UGF improvement / post mixer LPF investigation (with in 2 weeks)

- MC/FSS

Riju measured the MC REFL PD transimpedance. See ELOG and related.

- ASC

Why do we want to see less PRM motion? I thought PRC motion was causing
LSC issue of the central part. We wanted to maximize the PRM effect, don't we?
(Or is this to supress ETM motion during full lock?)

  10386   Thu Aug 14 15:51:37 2014 JenneUpdateGeneralUpdated game plan

Quote:

 - ALS

End PDH UGF improvement / post mixer LPF investigation (with in 2 weeks)

- MC/FSS

Riju measured the MC REFL PD transimpedance. See ELOG and related.

- ASC

Why do we want to see less PRM motion? I thought PRC motion was causing
LSC issue of the central part. We wanted to maximize the PRM effect, don't we?
(Or is this to supress ETM motion during full lock?)

 End PDH - good point, thanks.

ASC - Yes, this is so that we can use the POP QPD to feed back to the common ETMs after the CARM offset is already quite small.  We will not use POP DC QPD for PRC any more. 

Also, for future PRC ASC, I keep coming back to this in my head, but maybe it is less painful to install oplevs for PR2, PR3 than it would be to make an RF QPD.  Neither is going to be trivially easy.  But if we had sensors of the tip tilt motions, we could feed all of that back to the PRM to stabilize the PRC.

  10387   Thu Aug 14 18:02:11 2014 KojiUpdateGeneralUpdated game plan

Got the idea of ASC.

- Oplevs for PR2, PR3 => PR2 seems OK. PR3 almost impossible. well turned out not too crazy. We need outside electronics.

- RF QPD => not trivial and very technical but possible. All outside work.

- Better TT => might be a good solution.

  10388   Thu Aug 14 18:05:05 2014 JenneUpdateGeneralUpdated game plan

Quote:

- Oplevs for PR2, PR3 => Almost impossible.

 Because of the limited table space inside?  That's the main reason I can think of that this method is hard.  Am I missing something?

  10423   Fri Aug 22 13:51:00 2014 JenneUpdateGeneralUpdated game plan

40mToDoList.pdf

  4212   Thu Jan 27 15:16:43 2011 josephbUpdateCDSUpdated generate_master_screens.py

I modified the generate_master_screens.py script in /opt/rtcds/caltech/c1/medm/master/ to handle changing the MCL (and MC_L) listings to ALS for the two ETM suspension screens and associated sub-screens.

The relevant added code is:

custom_optic_channels = ['ETMX',
{'MCL':'ALS','MC_L':'ALS'},
'ETMY',
{'MCL':'ALS','MC_L':'ALS'}]

 

for index in range(len(custom_optic_channels)/2):
   if optic == custom_optic_channels[index*2]:
     for swap in custom_optic_channels[index*2+1]:
       sed_command = start_sed_string + swap + "/" + custom_optic_channels[index*2+1][swap] + middle_sed_string + optic + file
       os.system(sed_command)

When run, it generates the correctly named C1:SUS-ETMX_ALS channels, and replaces MCL and MC_L with ALS in the matrix screens.

 

  11745   Tue Nov 10 02:34:28 2015 gautamUpdateLSCUpdated interpretation of peaks

After thinking about the interpretation of the various peaks seen in the scan through 2 FSRs, I have revised the information presented in the previous elog. Yutaro pointed out that the modulation frequency isn't exactly 11MHz, but according to this elog, is 11.066209 MHz. So instead of using mod(11e6,FSR), I really should have been using mod(11.066209,FSR) and mod(5*11.066209,FSR) to locate the positions of the 11MHz and 55MHz sidebands relative to the carrier resonances. With this correction, the 'unknown' peaks identified in Attachment #1 in elog 11743 are in fact the 55MHz sideband resonances. 

However, this means that the peaks which were previously identified as 55MHz sideband resonances have to be interpreted now - I'm having trouble identifying these. If we assume that the types of peaks present in the scan are 11 MHz sideband, 55MHz sideband, and the TEM00, TEM10, TEM20, TEM30, and TEM40 mode resonances, then the peaks marked in grey in Attachment #1 to this elog can be interpreted as TEM30 (right of a carrier resonance) and TEM40 (left of a carrier resonance) mode resonances - however, the fitted center frequencies differ from the expected center frequencies (determined using the same method as elog 469) by ~3% (for TEM30) and ~20% (for TEM40) - therefore I am skeptical about these peaks, particularly the 4th HOM resonances. In any case, they are the smallest of all the peaks, and any correction due to them will be small. 

The updated modulation depths are as follows (computed using the same method as described in elog 11743, the updated plot showing the ratio of bessel functions as a function of the modulation depth is Attachment #2 in this elog):

@11.066209 MHz ---- 0.179

@5*11.066209 MHz --- 0.226

These numbers are now reasonably consistent with those reported in elog10211.

As for the mode-matching efficiency, the overall number is almost unchanged if I assume the TEM30 peaks are accurately interpreted: 92.11%. But the dominant HOM contribution comes from the first HOM resonance: (TEM00 = 1, TEM20 = 0.0325, TEM10 = 0.0475, TEM30 =  0.0056). These numbers may change slightly if the 4th HOM resonances are also correctly identified.

ETMx is still not well behaved and the mode cleaner isnt too happy either, so I think we will save the measurement of the round trip arm loss for daytime tomorrow.  

Attachment 1: Y_scan.pdf
Y_scan.pdf
Attachment 2: modDepth.pdf
modDepth.pdf
  11746   Tue Nov 10 11:06:02 2015 yutaroUpdateLSCUpdated interpretation of peaks
Quote:
Quote:

- modulation depth = 0.390 +/- 0.062

There are two modulation frequencies that make it to the arm cavities, at ~11MHz and ~55MHz. Each of these will have their own modulation depth indepedent of each other. Bundling them together into one number doesn't tell us what's really going on. 

 

I'm sorry. I misunderstood two things when writing elog 11741: the number of modulation frequencies, and how to distinguish modulation peaks and HOM peaks.

 

Now, I report about interpretation of the peaks marked in grey in Attachment #1 in elog 11745.

Summary:

The peaks marked in grey are interpreted as 3rd and 4th HOM resonance, if we assume that the radius of curvature of ETMY is slightly different from measured value. (measured: 57.6 m --> assumed: 59.3 m)

 

What I have done:

I plotted the differences in frequency between HOM peaks and 00 mode peaks (see Attachment #1) vs. expected orders of modes. The plot is shown in Attachement #2.

By fitting these data points, I calculated most likely value of gradient of this plot. This value corresponds: g_ITMYg_ETMY=0.3781. However, measured data of the radii of curvature suggests that g_ITMYg_ETMY=0.358. Assuming that this disagreement comes from the difference between measured and real values of ROC of ETMY (ITM is almost flat so that change of ROC of ITM doesn't have significant effect on g_ITMg_ETM), ROC of ETMY should be 59.3 m, different from measured value 57.6 m.

 

What I'd like to know:

-- Is such disagreement of ROC usual? Could it happen?

-- Are there any other possible explanations for this disagreement (or interpretations of the peaks marked in grey)?

Attachment 1: HOMlocation.png
HOMlocation.png
Attachment 2: homfit.png
homfit.png
  11747   Tue Nov 10 11:40:03 2015 KojiUpdateLSCUpdated interpretation of peaks

What is the uncertainty of your RoC estimation?

One measurement of the ETMY ROC was 57.6m, but we trust another measured value of 60.26m than the other.
The value is always dependent on the spotposition on the mirror and how the ROC is calculated from the mirror phase map (e.g. spotsize, averaging method).
So I don't think this is a huge deviation from the spec.

  11748   Tue Nov 10 11:41:56 2015 KojiUpdateLSCUpdated interpretation of peaks

FYI: I've also reported the similar mod depths of

11M: 0.194
55M: 0.234

in ELOG11036 with a different kind of measurement method.

  11749   Tue Nov 10 16:34:00 2015 yutaroUpdateLSCUpdated interpretation of peaks
Quote:

What is the uncertainty of your RoC estimation?

The uncertainty came from the residual of linear fitting and based on my estimation,

ROC_ETMY = 59.3 +/- 0.1 m.

 

And I attach the updated figure of the fitting (with residual zoomed up).

Data points in the lower are (intentionally) slightly shifted horizontally to make it easy for us to see them.

It is hard, I think, to estimate the error of each data point, but I used 17 kHz for the errors of all data points; 17 kHz is the error of FSR estimation of this measurement, and since FSR is the distance between two carrier peaks we can consider that HOM distances, which are the distance between carrier peaks and HOM peaks, have similar order errors comared with that of FSR. 

Attachment 1: homfit2.png
homfit2.png
  2872   Mon May 3 16:53:27 2010 josephbUpdateCDSUpdated lsc.mdl and the ifo plant model with memory locations

I've updated the LSC and IFO models that Rana created with new shared memory locations.  I've used the C1:IFO- for the ifo.mdl file outputs, which in turn are read by the lsc.mdl file.  The LSC outputs being lsc control signals are using C1:LSC-.  Optics positions would presumably be coming from the associated suspension model, and am currently using SUP, SPX, and SPY for the suspension plant models (suspension vertex, suspension x end, suspension y end).

I've updated the web view of these models on nodus.  They can be viewed at: https://nodus.ligo.caltech.edu:30889/FE/

I've also created a C1.ipc file in /cvs/cds/caltech/chans/ipc  which assigns ipcNum to each of these new channels in shared memory.

  4344   Wed Feb 23 11:53:30 2011 josephbUpdateCDSUpdated mx drivers

Alex and I updated the open mx drivers from 1.3.3 to 1.3.901 (1.4 release candidate).  We downloaded the drivers from: http://open-mx.gforge.inria.fr/

We put them in /root/open-mx-1.3.901 on the fb machine (and thus get mounted by all the front ends.).  We did configure and make and make install.

We did a quick check with /opt/mx/bin/mx_info on the fb machine at this point and realized the MAC addresses and host names were all messed up, including two listings for c1iscex with different mac addresses (neither of which was c1iscex).

We then brought all the front ends mx_streams down, brought the fb down, then cleared all the peer names with mx_hostname.  We then brought the fb up, and the front end mx_stream processes.

/opt/mx/mx_info now shows a clean and correct set of hostnames and mac addresses.  Testpoints and trends are working.

  3546   Wed Sep 8 14:44:37 2010 josephbUpdateCDSUpdated parse_mdl_to_ipc.py and feCodeGen.pl

I updated parse_mdl_to_ipc.py to correctly work with the 3 new cdsIPCx parts, namely cdsIPCx_PCIE (for dolphin connections), cdsIPCx_RFM (for our traditional reflected memory connections), and cdsIPCx_SHMEM (local shared memory on the computer).  These parts replaced cdsIPCx awhile back (see here ).

The code now correctly counts each type independantly with regards to ipcNum (I.e. you can have ipcNum = 0 for RFM and ipcNum = 0 for SHMEM for example).

 

I also went in and modified a few sections of the feCodeGen.pl (in /opt/rtcds/caltech/c1/core/advLigoRTS/src/epics/util/) so as to properly assign names to matrix adl files, matrix of filter bank adl files, and filter bank adl files.

  15429   Wed Jun 24 22:47:21 2020 YehonathanUpdateWikiUpdated phase maps webpage
I uploaded the new phase maps measurements made by GariLynn to nodus and updated the optics phase maps page.
I also added MetroPro and Matlab analysis for these phase maps.
  10108   Fri Jun 27 18:07:38 2014 NichinUpdateComputer Scripts / ProgramsUpdated script for acquiring data from Agilent 4395A network analyzer

The updated script for remotely getting data from Agilent 4395A network analyzer is located at /users/nichin

This network analyzer device is located at crocetta.martian (192.168.113.108)

How to run the script:

> python NWAG4395A_modified.py [filename.yml]

  1. The script accepts sweep parameters and output options via a .yml file that is written following a template that can be found at /users/nichin/NWAG4395template.yml
  2. The data obtained is stored as a .dat file and the corresponding details regarding the acquired data is in a .par parameter file
  3. You can choose to get a plot of the data obtained by specifying it in the .yml file. The plots are automatically stored as PDF.
  4. Plots, data and parameter files are all stored in a new folder that is created with a timestamp in its name.
  5. NOTE: Plotting options are only available in computers running numpy versions of 1.6.0 or above. The plotting sections of the code worked on Chiara, which has a 1.6.1 numpy, but did not work on Rossa which only had 1.3.0 numpy. Anyway, I have added an extra function that checks the version and skips the plotting part if needed.

Test Run:

I connected a simple 2MHz Low pass filter between the modulation output and signal input of the NA and ran a scan from 0Hz to 20MHz. The script was run from Chiara.

The expected plot was obtained and is attached here.

Further work:

I now have to work on setting up the RF switch in rack 1Y1 to select between required PDs and also on the code that chooses which channel is being selected.

There is also a problem of 2 8x1 RF switches being present, instead of one 16x1. Alex's code for RF switching does not take this into account.

RXA: I've deleted your plot because it didn't meet the minimal Bode plot standards. Please look up "Bode Plot" using Google/Wikipedia and try to follow some good example. Bode plot should contain Phase as well as magnitude. Also, the axes must be labeled with some physical units.

  10111   Mon Jun 30 00:18:15 2014 NichinUpdateComputer Scripts / ProgramsUpdated script for acquiring data from Agilent 4395A network analyzer

Quote:

 

RXA: I've deleted your plot because it didn't meet the minimal Bode plot standards. Please look up "Bode Plot" using Google/Wikipedia and try to follow some good example. Bode plot should contain Phase as well as magnitude. Also, the axes must be labeled with some physical units.

Sorry Rana for not giving much attention to the plot. I will definitely change the way they are being plotted.

I was more focused on getting the data acquisition to work. Also, the current script gets only the magnitude and not the phase... I still have to work on that.

  4134   Tue Jan 11 13:32:52 2011 josephb, kiwamuUpdateCDSUpdated some DAQ channel names

[Joe, Kiwamu]

We modified the activateDAQ.py script which lives in /opt/rtcds/caltech/c1/chans/daq/ and updates the C1SUS.ini, C1MCS.ini, C1RMS.ini, C1SCX.ini and C1SCY.ini files.  These files contain the DAQ channels for all the optics.

It has been modified so that channels like C1:SUS-ITMX_ULSEN_OUT_DAQ become C1:SUS-ITMX_SENSOR_UL.  Similarly the oplev signals go from C1:SUS-ITMX_OLPIT_OUT to C1:SUS-ITMX_OPLEV_PERROR.

After some debugging, we ran the script successfully and checked the output was correct.  We then restarted the frame builder (telnet fb 8088 and then shutdown) and also hit the DAQ reload button for all the front ends.

I tested in dataviewer that I could go back several years as well as going back just 1 hour in the history and see data for C1:SUS-ITMX_SENSOR_LL as well as C1:SUS-ITMX_OPLEV_YERROR.  I also tested realtime is also working for these channels.

 

The contents of the script are below.

 

inputfiles=["C1SUS.ini","C1RMS.ini","C1MCS.ini","C1SCX.ini","C1SCY.ini"]
prefix="[C1:SUS-"
optics=["BS_","ITMX_","ITMY_","PRM_","SRM_","MC1_","MC1_","MC2_","MC3_","ETMX_"]
#channels=["SUSPOS_IN1","SUSPIT_IN1","SUSYAW_IN1","SUSSIDE_IN1","ULSEN_OUT","URSEN_OUT","LRSEN_OUT","LLSEN_OUT","SDSEN_OUT","OL_SUM_IN1","OLPIT_IN1","OLYAW_IN1"]
channels_dict = {'SUSPOS_IN1':'SUSPOS_IN1_DAQ',
'SUSPIT_IN1':'SUSPIT_IN1_DAQ',
'SUSYAW_IN1':'SUSYAW_IN1_DAQ',
'SUSSIDE_IN1':'SUSSIDE_IN1_DAQ',
'ULSEN_OUT':'SENSOR_UL',
'URSEN_OUT':'SENSOR_UR',
'LRSEN_OUT':'SENSOR_LR',
'LLSEN_OUT':'SENSOR_LL',
'SDSEN_OUT':'SENSOR_SIDE',
'OLPIT_OUT':'OPLEV_PERROR',
'OLYAW_OUT':'OPLEV_YERROR',
'OL_SUM_OUT':'OPLEV_SUM'}

suffix="_DAQ]\n"

## set datarate
datarate=2048

## read the ini files
for inputfile in inputfiles:
    print inputfile
    outputfile=inputfile
    ifile = open(inputfile,'r')
    lines = ifile.readlines()
    ifile.close()

    for k in range(len(lines)):
        for op in optics:
            for ch in channels_dict:
                if (prefix+op+ch+suffix) in lines[k]:
                    lines[k]=prefix + op + channels_dict[ch] + "]\n"
                    lines[k+1]=lines[k+1].lstrip("#").rstrip(lines[k+1].split("=")[1])+"1\n"
                    lines[k+2]=lines[k+2].lstrip("#")
                    lines[k+3]=lines[k+3].lstrip("#").rstrip(lines[k+3].split("=")[1])+str(datarate)+"\n"
                    lines[k+4]=lines[k+4].lstrip("#")
    ofile = open(outputfile,'w')
    for k in range(len(lines)):
        ofile.write(lines[k])
        #print lines[k]
    ofile.close()

  4160   Fri Jan 14 20:39:20 2011 ranaUpdateCDSUpdated some DAQ channel names

I like this activateDAQ script, but someone (Jenne with Joe's help) still needs to add the PEM channels - we still cannot see any seismic trends.

  4292   Mon Feb 14 21:59:35 2011 ranaUpdateCDSUpdated some DAQ channel names

Although Joe and Kiwamu claim that they have inserted the correct DAQ names for the OPLEVs (e.g. PERROR and YERROR) back in Jan. 11, when I look today, I see that these channels are missing!

I want my PERROR/YERRORs back!

 

  4300   Tue Feb 15 11:56:17 2011 josephbUpdateCDSUpdated some DAQ channel names
That is my fault for not running the activateDAQ.py script after a round of rebuilds. I have run the script this morning, and confirmed that the oplev channels are showing up in dataviewer.

Quote:

Although Joe and Kiwamu claim that they have inserted the correct DAQ names for the OPLEVs (e.g. PERROR and YERROR) back in Jan. 11, when I look today, I see that these channels are missing!

I want my PERROR/YERRORs back!

 

 

  10957   Thu Jan 29 16:14:10 2015 manasaUpdateGeneralUpdated to do list for FOL

Since there will be some work that supposedly will involve moving stuff on the table and racks; here is the updated to-do list for FOL.

  14461   Fri Feb 15 20:07:02 2019 JonUpdateVACUpdated vacuum punch list

While working on the vac controls today, I also took care of some of the remaining to-do items. Below is a summary of what was done, and what still remains.

Completed today

  • TP2/3 overcurrent interlock raised from 1 to 1.2 A. This was tripping during normal operation as the pump accelerates from low-speed (standby) to normal-speed mode.
  • Interlock conditions on VABSSCO/VABSSCI removed. Per discussion with Steve, these are not vent valves, but rather isolation valves between the BS/IOO/OMC annuli. The interlocks were preventing the valves from opening, and hence the IOO and OMC annuli from being pumped.
  • Channel exposed for interlocking in-vacuum high-voltage drivers. The channel name is C1:Vac-interlock_high_voltage. The vac interlock service sets this channel's value to 0 when the main volume pressure is in the range 3 mtorr-500 torr, and to 1 otherwise.
  • Annuli pumping integrated into the set of recognized states. "Vacuum normal" now refers to TP1 and TP2 pumping on the main volume AND TP3 pumping on all the annuli. The system is currently running in this state.
  • TP1 lowered to the nominal speed setting recommended by Steve: 33.6 krpm (560 Hz).

Still remaining

  • Implement a "blinker" input-output signal loop between two Acromags to detect hardware failures like the one today.
  • Add an AC power monitor to sense extended power losses and automatically put the system into safe shutdown.
  • Migrate the RGA to c1vac. Still some issues getting the serial comm working.
  • Troubleshoot the SuperBee (backup) main volume Parani gauge. It has not communicated with c1vac since a serial adapter was replaced two weeks ago. Chub thinks the gauge was possibly damaged by arcing during the replacement.
  • Scripting for more automated pumpdowns.
  • Generate a bootable backup hard drive for c1vac, which could be swapped in on a short time scale after a failure.
  2267   Fri Nov 13 14:04:27 2009 josephb, kojiUpdateComputersUpdated wiki with RCG instructions/tips

I've placed some notes pertaining to what Koji and I have learned today about getting the RCG code working on the 40m wiki at:

http://lhocds.ligo-wa.caltech.edu:8000/40m/Notes_on_getting_the_CDS_Realtime_Code_Generator_working

We're still trying to fix the tst system, as the moment its reporting an invalid number of daq channels and during daq initialization it fails.  (This from the /cvs/cds/caltech/target/c1tst/log.txt file). Note: This problem is only on megatron and separated from the conventional DAQ system of the 40m.

cpu clock 2800014
Warning, could open `/rtl_mem_tst' read/write (errno=0)
configured to use 2 cards
Initializing PCI Modules
2 PCI cards found
***************************************************************************
1 ADC cards found
        ADC 0 is a GSC_16AI64SSA module
                Channels = 64
                Firmware Rev = 512

***************************************************************************
1 DAC cards found
        DAC 0 is a GSC_16AO16 module
                Channels = 16
                Filters = None
                Output Type = Differential
                Firmware Rev = 3

***************************************************************************
0 DIO cards found
***************************************************************************
0 IIRO-8 Isolated DIO cards found
***************************************************************************
0 IIRO-16 Isolated DIO cards found
***************************************************************************
0 Contec 32ch PCIe DO cards found
0 DO cards found
***************************************************************************
0 RFM cards found
***************************************************************************
Initializing space for daqLib buffers
Initializing Network
Found 1 frameBuilders on network
Waiting for EPICS BURT at 0.000000 and 0 ns 0x3c40c004
BURT Restore = 1
Waiting for Network connect to FB - 10
Reconn status = 0 1
Reconn Check = 0 1
Initialized servo control parameters.
DAQ Ex Min/Max = 1 32
DAQ Tp Min/Max = 10001 10094
DAQ XTp Min/Max = 10094 10144
DAQ buffer 0 is at 0x8819a020
DAQ buffer 1 is at 0x8839a020
daqLib DCU_ID = 10
DAQ DATA INFO is at 0x3e40f0a0
Invalid num daq chans = 0
DAQ init failed -- exiting

  2268   Fri Nov 13 15:01:07 2009 JenneUpdateComputersUpdated wiki with RCG instructions/tips

Quote:

I've placed some notes pertaining to what Koji and I have learned today about getting the RCG code working on the 40m wiki at:

http://lhocds.ligo-wa.caltech.edu:8000/40m/Notes_on_getting_the_CDS_Realtime_Code_Generator_working

We're still trying to fix the tst system, as the moment its reporting an invalid number of daq channels and during daq initialization it fails.  (This from the /cvs/cds/caltech/target/c1tst/log.txt file).

 Dmass tells me that you have to record at least one channel.  ie at least one channel in your .ini file must be set to acquire, otherwise the DAQ will flip out.  It seems to be unhappy when you're not asking it to do things.

  2269   Fri Nov 13 22:01:54 2009 KojiUpdateComputersUpdated wiki with RCG instructions/tips

I continued on the STAND ALONE debugging of the megatron codes.

- I succeeded to run c1aaa with ADC/DAC. (c1aaa is a play ground for debugging.)

  The trick was "copy DAC block from sam.mdl to aaa.mdl".
  I don't understand why this works. But it worked.
  I still have the problem of the matrices. Their medm screens are always blank. Needs more works.

- Also I don't understand why I can not run the build of c1tst when I copy the working aaa.mdl to tst.mdl.

- The problem Joe reported: "# of channels to be daqed" was solved by

make uninstall-daq-aaa
make install-daq-aaa

  This command is also useful.

daqconfig

- Now I am in the stable development loop with those commands

killaaa
make uninstall-daq-aaa
make aaa
make install-aaa
make install-daq-aaa
make install-screens-aaa
startaaa

  I have made "go_build" script under /home/controls/cds/advLigo

usage:
./go_build aaa

- Note for myself: frequently visited directories

/home/controls/cds/advLigo/src/epics/simLink (for model)
/home/controls/cds/advLigo
(to build)
/cvs/cds/caltech/target/c1aaa
(realtime code log)
/cvs/cds/caltech/target/c1aaaepics (ioc log)
/cvs/cds/caltech/medm/c1/aaa (medm screens)
/cvs/cds/caltech/chans
(filter coeffs)
/cvs/cds/caltech/chans/daq (daq settings)

  2270   Sat Nov 14 06:46:48 2009 KojiUpdateComputersUpdated wiki with RCG instructions/tips

I am still working on the c1aaa code. Now it seems that C1AAA is working reasonably (...so far).

1) At a certain point I wanted clean up the system status. I have visited /etc/rc.local to add c1aaa for realtime to non-realtime task

before:
/usr/bin/setup_shmem.rtl mdp mdc tst&
after:
/usr/bin/setup_shmem.rtl mdp mdc tst aaa&

   I rebooted the system several times.

sudo /sbin/reboot

2) I found that gabage medm screens accumulated in ~/cds/advLigo/build/aaaepics/medm after many trials with several simulink models.
This directory is always copied to /cvs/cds/caltech/medm/c1/aaa at every make install-screens-aaa
This caused very confusing MEDM screens in the medm dir like C1AAA_ETMX_IN_MATRX.adl (NOT ETMY!)

I did

cd ~/cds/advLigo
make clean-aaa

to refresh aaaepics dir. The current development procedure is

killaaa
make clean-aaa
make uninstall-daq-aaa
make aaa
make install-aaa
make install-daq-aaa
make install-screens-aaa
startaaa

3) Sometimes startaaa does not start the task properly. If the task does not work, don't abandon.
Try restart the task. This may help. 

killaaa
(deep breathing several times)
startaaa

What to do next:

- MEDM works

* make more convenient custom MEDM screens so that we can easily access to the filters and switches
* retrofit the conventional SUS MEDM to the new system

- once again put/confirm the filter coeffs and the matrix elements

- configure DAQ setting so that we can observe suspension motion by dataviewer / dtt

- connect the suspension to megatron again

- test the control loop

  2278   Tue Nov 17 00:42:12 2009 KojiUpdateComputersUpdated wiki with RCG instructions/tips

Dmass, Joe, Koji


A puzzle has been solved: Dmass gave us a great tip

"The RGC code does not work unless the name of the mdl file (simulink model) matches to the model name "

The model name is written in the second line. This is automatically modified if the mdl file is saved from simulink.
But we copied the model by using "cp" command. This prevent from the TST model working!

megatron:simLink>head tst.mdl
Model {
  Name                    "tst"
  Version                 7.3
  MdlSubVersion           0

...
...
...

This explained why the AAA model worked when the DAC block has been copied from the other model.
This was not because of the ADC block but the saving model fixed the model name mismatch!


Now our current working model is "C1TST". Most of the functionalities have been implemented now:

  • The simulink model has been modified so that some of the functionalities can be accomodated, such as LSC/ASC PIT/ASC YAW.
  • Some filter names are fixed so as to inherit the previous naming conventions.
  • The SUS-ETMY epics screen was modified to fit to the new channel names, the filter topologies, and the matrices.
  • The chans file was constructed so that the conventional filter coefficients are inherited.
  • All of the gains, filter SWs, matrix elements have been set accordingly to the current ETMY settings.
  • burt snapshot has been taken: /cvs/cds/caltech/target/c1tstepics/controls_1091117_024223_0.snap
    burtrb -f /cvs/cds/caltech/target/c1tstepics/autoBurt.req -o controls_1091117_024223_0.snap -l /tmp/controls_1091117_024215_0.read.log -v

What to do next:

  • Revisit Oplev model so that it accomodates a power normalization functionality.
  • ETMY QPD model is also missing!
  • Clean up mdl file using subsystem grouping
  • Check consistency of the whitening/dewhitening switches.
  • Connect ADC/DAC to megatron
  • Test of the controllability
  • BTW, what is happened to BIO?
  • Implementation of the RFM card

Directories and the files:

  • The .mdl file is backed up as
    /home/controls/cds/advLigo/src/epics/simLink/tst.mdl.20091116_2100

  • The default screens built by "make" is installed in
    /cvs/cds/caltech/medm/c1/tst/
    They are continuously overridden by the further building of the models.

  • The custom-built medm screens are stored in
    /cvs/cds/caltech/medm/c1/tst/CustomAdls/

    The backup is
    /cvs/cds/caltech/medm/c1/tst/CustomAdls/CustomAdls.111609_2300/

  • The custom-built chans file is
    /cvs/cds/caltech/chans/C1TST.txt

    The backup is
    /cvs/cds/caltech/chans/C1TST.111609

  • burt snap shot file
    /cvs/cds/caltech/target/c1tstepics/controls_1091117_024223_0.snap
  16001   Tue Apr 6 18:46:36 2021 Anchal, PacoUpdateSUSUpdates on recent efforts

As mentioned in last post, we earlier made an error in making sure that all time series arrays go in with same sampling rate in CSD calculation. When we fixed that, our recursive method just blew out in all the efforts since then.


We suspect a major issue is how our measured sensing matrix (the cross-coupling matrix between different degrees of freedom on excitation) has significant imaginary parts in it. We discard the imaginary vaues and only use real parts for iterative method, but we think this is not the solution.

Here we present cross-spectral density of different channels representing the three sensed DOFs (normalized by ASD of no excitation data for each involved component) and the sensing matrix (TF estimate) calculated by normalizing the first cross spectral density plots column wise by the diagonal values. These are measured with existing ideal output matrix but with the new input matrix. This is to get an idea of how these elements look when we use them.

Note, that we used only 10 seconds of data in this run and used binwidth of 0.25Hz. When we used binwidth of 0.1 Hz, we found that the peaks were broad and highest at 13.1 Hz instead of 13 Hz which is the excitation frequency used in these measurements.


How should we proceed?

  • We feel that we should figure out a way to use the imaginary value of the sensing matrix, either directly or as weights representing noise in that particular data point.
  • Should we increase the excitation amplitude? We are currently using 500 counts of excitation on coil output.
  • Are there any other iterative methods for finding the inverse of the matrix that we should be aware of? Our current method is rudimentary and converges linearly.
  • Should we use the absolute value of the sensing matrix instead? In our experience, that is equivalent to simply taking ratios of the PSD of each channel and does not work as well as the TF estimate method.
Attachment 1: FirstMeasurementPlots.pdf
FirstMeasurementPlots.pdf FirstMeasurementPlots.pdf
ELOG V3.1.3-