Back from dinner. Taking measurements.

I measured the transfer function between MC_TRANS and TRX and I'm attaching the result.

That looks quite strange. Something's wrong. I'll repeat it tomorrow.

for the night I'm putting everything back. I'm also reconnecting the OMC_ISS_EXC and opening again the test switch on the ISS screen.

The RFAM monitor remains disable

I would have guessed that you have to calibrate the detectors relative to each other before trying this. Its also going to be tricky if you use 2 different kinds of ADC for this (c.f. today's delay discussion in the group meeting).

I think Osamu used to look at fast transmission signals by making sure the PD at the end had a 50 Ohm output impedance and just drive the 40m long cable and terminate the receiving end with 50 Ohms. Then both PDs go into the SR785.

I found elog got crashed. I rebooted the elog daemon just 10minutes before.

The on/off switch for the drill press is broken.  Replacement parts should be here tomorrow. 

Joe, Peter, Jay, Koji, Rana

We put the new CDS stuff at Y end 1Y9 rack.

Items

• megatron
• wireless router
• IO chasis (black)
• Extention cable (between megatron & IO chasis)
• 1 ADC card
• 1 DAC card
• 1 BIO card
• The adapter box for ADC
• The adapter box for DAC
• The adapter box for BIO
• 2x IDC-DB37 cable for the ADC box - AA chasis
• 1x IDC cable for the DAC box - Pentek
• 1x DB cable for the BIO box
• 1x +/-15V cable for the BIO box

 Joe and I moved megatron and its associated IO chassis from 1Y3 to 1Y9, in preparations for RCG tests at ETMY.

On Rana's suggestion I measured the trasfer function between the two photodiodes PDA255 that I'm using.

I took the one that I had on the end table and put it on the PSL table. I split the MC transmitted beam with a 50% beam splitter and sent the beams on the two diodes. (Rana's idea of picking off the beam and interposing the PDs before the ISS PDs was not doable: ISS PDs would be too close and there would be no room to install the PDA255 before them). See picture with the final setup.

The transfer function also includes the 40m long cable that I was using for the Arm Cavity measurement.

Here's what I got. It looks rather flat. Yesterday the calibration was probably not the problem in that measurement.

 I'm now going to install the PD back on the end table and measure the TFs between the excitation and several points of the loop.

(Trivia. At first, the PDs were saturating so Koji attached attenuation filters on to them. Suddenly the measurement got much nicer)

It seems that just repeating the measurement was enough to get a good transfer function of the x arm cavity. Here's what I got.

I'm going to fit the data on matlab, but at first sight, the pole seems to be at about 1.7KHz (that is where the phase is 45deg): as expected.

Probably it was useful to realign the beam on the Transmission PD. (btw, I'm using the PDA255 that was still on the X end table since the AbsL experiemtn that measured the arm length)

As for the X Arm, this the transfer function I measured for the Y arm cavity.

This time I'm using a different photodiode than the PDA255 on the Y end table.

The diode I'm using is the PDA520 from where TRY comes from.

I'm going to repeat the measurement with PDA255.

 Measurement repeated with the PDA255 PD at the end but not big changes

I disconnected the setup for the arm cavity TF measurement. I opened the scitation switch on the ISS medm screen. I reconnected the OMC ISS EXC cable to the breakout box on the floor.

The photodiode on the Y end is stilll connected.

Also the RFAm (whish is not disbaled anymore) still has a 50% beam splitter before it.

I'm also running the Align Full IFO script.

The RFMnetwork is down.  MC2 sus damping restored.

As noted by Steve, the RFM network was down this morning.  I noticed that c1susvme1 sync counter was pegged at 16384, so I decided to start with reboots in that viscinity.

After power cycling crates containing c1sosvme, c1susvme1, and c1susvme2 (since the reset buttons didn't work) only c1sosvme and c1susvme2 came back normally.  I hooked up a monitor and keyboard to c1susvme1, but saw nothing.  I power cycled the c1susvme crate again, and this time I watched it boot properly.  I'm not sure why it failed the first time.

The RFM network is now operating normally.  I have re-enabled the watchdogs again after having turned them off for the reboots.  Steve and I also re-enabled the ITMY coil drivers when I noticed them not damping once the watch dogs were re-enabled.  The manual switches had been set to disabled, so we re-enabled them.

  In this experiment, we used a feedback control to create a stable trap for a NdFeB permanent magnet. The block diagram is the following:

signal into another  SR560 as a low-pass filter with a gain of 100 above 30 Hz. We used the "DC" coupling modes in both

preamplifers. The output is then used to drive a coil. The coil has a dimension of 1.5 inch in diameter and 2 inch in length.

The inductance of the coil is around 0.5 H and the resistance is 4.7 Om. Therefore, it has a corner frequency aournd 10/2pi Hz.

The coil has a iron core inside to enhance the DC force to the permanent magnet. The low-frequency 1/f response of the magnet is produced

by the eddy current damping of the aluminum plane that is below the magnet. This 1/f response is essential for a stable configuration. In the

next stage, we will remove the aluminum plane, and instead we will use a filter to create similar transfer function. At high-frequencies, it behaves as 

a free-mass and has a 1/f^2 response. Finally, the magnet is stably levitated.

The Ranger seismometer has been moved to ~the middle of the Mode Cleaner tube, and it's orientation has been changed to horizontal (using all of the locking/mass centering procedures).  This is similar in orientation to the way things were back in the day when Rana and Matt had the OAF running nicely.

While I was writing up an elog entry, the elog died again, and I restarted it.  Not sure what caused it to die since no one was uploading to it at the time.

I have removed the RFM card from Megatron and left it (along with all the other cables and electronics) on the trolly in front of the 1Y9 rack.

Megatron proceeded to boot normally up until it started loading Centos 5.  During the linux boot process it checks the file systems.  At this point we have an error:

/dev/VolGroup00/LogVol00 contains a file system with errors, check forced

Error reading block 28901403 (Attempt to read block from filesystem resulted short read) while doing inode scan.

/dev/VolGroup00/LogVol00 Unexpected Inconsistency; RUN fsck MANUALLY

So I ran fsck manually, to see if I get some more information.  fsck reports back it can't read block 28901403 (due to a short read), and asks if you want to ignore(y)?.  I ignore (by hitting space), and unfortunately touch it an additional time.  The next question it asks is force rewrite(y)?  So I apparently forced a rewrite of that block.  On further ignores (but no forced rewrites) I continue seeing short read errors at 28901404, *40, *41,*71, *512, *513, etc.  So not totally continugous.  Each iteration takes about 5-10 seconds.  At this point I reboot, but the same problem happens again, although it starts 28901404 instead of 28901403.  So apparently the force re-write fixed something, but I don't know if this is the best way of going about this.  I just wondering if there's any other tricks I can try before I just start rewriting random blocks on the hard drive.  I also don't know how widespread this problem is and how long it might take to complete (if its a large swath of the hard drive and its take 10 seconds for each block that wrong, it might take a while).

So for the moment, megatron is not functional.  Hopefully I can get some advice from Alex on Monday (or from anyone else who wants to chime in).  It may wind up being easiest to just wipe the drive and re-install real time linux, but I'm no expert at that.

  Koji, Joe, and I are planning to try controlling the ETMY, on Monday or Tuesday.  Our plan is to try to do this with megatron out of the RFM loop.   The RCG system includes pos, pit, yaw, side, and oplevs.  I will use matrix elements as currently assigned (i.e. not the ideal case of +1 and -1 everywhere).   I will also match channel names to the old channels.   We could put buttons on the medm screen to control the analog DW by hand.  

Something strange was going on in the OAF code, printf would print a double precision number in %f format but not in %lf or %e format!

Since we know this problem now, we can move forward, but it will be important to know why printf was restricted and if there are other such constraints which we should remember while making changes in the codes.

elog was acting up again (not running), so I restarted it. 

And again.  This makes 4 times since lunchtime yesterday....something bad is up.

I am using SR785 Spectrum Analyzer now and also tomorrow. 
I will put it back on Sunday. If anyone needs it during the weekend,
please just take it and I can reset it by myself later. Thanks.

I measured the open-loop transfer function of the magnetic levitation system.

The schematic block diagram for this measurement is the following:

I injected a signal at a level of 20mV between two preamplifiers, and the corresponding open-loop

transfer function is given by B/A.  I took a picture of the resulting measurement, because

I encountered some difficulties to save the data to the computer via the wireless network.

The bode plots for the transfer function shown on the screen is the following:

I am puzzled with the zero near 10 Hz. I think it should come from the mechanical response function, because there is no zero in the transfer functions

of the preamplifer and the coil itself. I am not sure at the moment.

The corresponding configuration of the levitated magnet is

This afternoon I re-enabled the ETMY coils after I found that the watchdogs for the mirror had tripped last night at 2:06am.

Tonight I aligned the IFO by running the scripts one by one.

SRC was far off and I had to align SRM by hand before the script could work. SPOB is still low when DRM is aligned.

I'm restoring the full IFO now that I'm taking off.

I used the coh_carpet.m function from the mDV to calculate this plot:

coh_carpet('C1:PEM-ACC_MC1_X','C1:PEM-ACC_MC2_X',gps('now - 3 days'),3600*12,4,10,64)

It shows the coherence v. time of two of our X-direction accelerometers starting around 1AM on Friday and going for 12 hours.

I'm not sure what it means exactly, but it looks like the coherence is relatively steady as a function of time. I will need more RAM than Rosalba or a smarter code to calculate longer time stretches.

MC2 damping restored,  MZ locked and the arms are flashing now.

I'm working on the PSL table to set up the PLL setup for the AbsL experiment.

Alex and I took a look at megatron this morning, and it was in the same state I left it on Friday, with file system errors.  We were able to copy the advLIGO directory Peter had been working in to Linux1, so it should be simple to restore the code.  We then tried just running fsck, and overwritting bad sectors, but after about 5 minutes it was clear it could potentially take a long time (5-10 seconds per unreadable block, with an unknown number of blocks, possibly tens or millions).  The decision was made to simply replace the hard drive.

Alex is of the opinion that the hard drive failure was a coincidence.  Or rather, he can't see how the RFM card could have caused this kind of failure.

Alex went to Bridge to grab a usb to sata adapter for a new hard drive, and was going to copy a duplicate install of the OS onto it, and we'll try replacing the current hard drive with it.

Apparently the random file system failure on megatron was unrelated to the RFM card (or at least unrelated to the physical card itself, its possible I did something while installing it, however unlikely).

We installed a new hard drive, with a duplicate copy of RTL and assorted code stolen from another computer.  We still need to get the host name and a variety of little details straightened out, but it boots and can talk to the internet.  For the moment though, megatron thinks its name is scipe11.

You still use ssh megatron.martian to log in though.

We installed the RFM card again, and saw the exact same error as before.  "NMI EVENT!" and "System halted due to fatal NMI".

Alex has hypothesized that the interface card the actual RFM card plugs into, and which provides the PCI-X connection might be the wrong type, so he has gone back to Wilson house to look for a new interface card.  If that doesn't work out, we'll need to acquire a new RFM card at some point

After removing the RFM card, megatron booted up fine, and had no file system errors.  So the previous failure was in fact coincidence.

I removed the beam splitter and the PDA 255.

the beam path to the RFAM photodiode is clear again.

 Drill press is all better now.  A spare switch is in the top drawer with the drill bits.

It won't start--it just sits at Waiting for EPICS BURT, even though the EPICS is running and BURTed.

[controls@c1omc c1omc]$ sudo ./omcfe.rtl
cpu clock 2388127
Initializing PCI Modules
3 PCI cards found
***************************************************************************
1 ADC cards found
        ADC 0 is a GSC_16AI64SSA module
                Channels = 64
                Firmware Rev = 3

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

***************************************************************************
0 DIO cards found
***************************************************************************
1 RFM cards found
        RFM 160 is a VMIC_5565 module with Node ID 130
***************************************************************************
Initializing space for daqLib buffers
Initializing Network
Waiting for EPICS BURT




From looking at the recorded data, it looks like the c1omc started going funny on the afternoon of Nov 5th, perhaps as a side-effect of the Megatron hijinks last week.

It works when megatron is shutdown.

To estimate the noise floor of the Ranger, Rana and I locked the mass on the seismometer, so there will be no (aka minimal) signal from the motion of the ground in the pickup coil.  We should be seeing primarily the noise of the readout electronics.  We also put the Ranger on top of one of the foam lids from the Seismometer Isolation Boxes to further isolate from ground motion (this didn't change the signal noticeably).  

In this plot, Green is the locked-mass-on-foam noise floor, blue is the regular spectra, with the SR560 AC coupled, and the red is the regular seismic spectra with the SR560 DC coupled.  There doesn't seem to be a noticeable difference between blue and red (the spectra were taken at different times of day, with the red taken at night, when we generally expect things to be quieter).  I'm leaving the SR560 DC coupled.  (Rana had found it earlier this afternoon GND coupled....not sure yet why).

Also, we're not sure that the green curve is true readout noise, vs. how much of it is specifically due to the fact that the mass is locked down.  Especially around a few hundred Hz, the green curve is much higher than the other 2, and at a few tens of Hz there is some weird peak action.  However, this will be okay as a first-run noise estimate for the Ranger's noise floor.

The question at hand is: Do we need to redo any of the Ranger's readout electronics (i.e. replace the SR560 with a Pomona Box circuit) to lower the noise floor, or is it okay as-is?

We found that someone had set the name of megatron to scipe11. This is the same name as the existing c1aux in the op440m /etc/hosts file.

We did a /sbin/shutdown on megatron and the OMC now boots.

Please: check to see that things are working right after playing with megatron or else this will sabotage the DR locking and diagnostics.

Last night around 5pm or so, Alex had remotely logged in and made some fixes to megatron.

First, he changed the local name from scipe11 to megatron.  There were no changes to the network, this was a purely local change.  The name server running on Linux1 is what provides the name to IP conversions.  Scipe11 and Megatron both resolve to distinct IPs. Given c1auxex wasn't reported to have any problems (and I didn't see any problems with it yesterday), this was not a source of conflict.  Its possible that Megatron could get confused while in that state, but it would not have affected anything outside its box.

Just to be extra secure, I've switched megatron's personal router over from a DMZ setup to only forwarding port 22.  I have also disabled the dhcp server on the gateway router (131.215.113.2).

Second, he turned the mdp and mdc codes on.  This should not have conflicted with c1omc.

This morning I came in and turned megatron back on around 9:30 and began trying to replicate the problems from last night between c1omc and megatron.  I called Alex and we rebooted c1omc while megatron was on, but not running any code, and without any changes to the setup (routers, etc).  We were able to burt restore.  Then we turned the mdp, mdc and framebuilder codes on, and again rebooted c1omc, which appeared to burt restore as well (I restored from 3 am this morning, which looks reasonable to me). 

Finally, I made the changes mentioned above to the router setups in the hope that this will prevent future problems but without being able to replicate the issue I'm not sure.

From fitting the arm cavity transfer functions I got the following values for the cavity pole frequencies.

X ARM: fp_x = (1720 +/- 70) Hz

Y ARM: fp_y = (1650 +/- 70) Hz

Attached are the plots from the fitting.

Aligning the beam for the PLL of the AbsL Experiement I rotated the polarizer along the path of the MC Input pick off beam (= the pick off coming from the MC periscope).

I've been trying to lock the PLL for the AbsL Experiment but I can't see the beat (between the auxiliary NPRO and the PSL).

I believe the alignment of the PLL is not good. The Farady Isolator is definitely not perfectly aligned (you can see it from the beam spot after it) but still it should be enough to see something at the PLL PD.

it's probably just that the two beams don't overlap well enough on the photodiode. I'll work on that later on.

I'm leaving the lab now. I left the auxiliary NPRO on but I closed its shutter.

All the flipping mirrors are down.

Mostly a note to self:  I have put terminators on the ADC inputs which are usually the PEM-SEIS-GUR2_(XYZ) channels.  Since these 3 signals are currently going into the ASS ADC, these PEM ADC inputs are open, and have predefined channel names.  I'll collect the data and put it as the ADC noise level in my nifty plot which will show the noise limits of all things which affect Wiener Filtering.

 I've added the side coil to the model controller and plant, and the oplev quad to the model controller and plant.  After the megatron wipe, the code now lives in /home/controls/cds/advLigo/src/epics/simLink.  The files are mdc.mdl (controller) and mdp.mdl (plant).  These RCG modules go at 16K with no decimation (no_oversampling=1 in the cdsParameters block) so hopefully will work with the old (16K) timing.

I've loaded many of the filters, there are some eft to do.  These filters are simply copied from the current frontend.  

Next I will port to the SUS module (which talks to the IO chassis).  This means channel names will match with the current system, which will be important when we plug in the RFM.

RFAMPD_DCMON disappered on Nov 5, 2009

The attached plot shows the spectra of the 3 Z axes of the 3 seismometers we have (this data is from ~20Aug2009, when the Ranger was in the Z orientation) in Magenta, Cyan and Green, and the noise of each of the sensors in Red, Blue and Black.  The noise curves were extracted from the spectra using the Huddle Test / 3 Corner Hat method.  The Blue and Black traces which are just a few points are estimates of the noise from other spectra.  The Blue points come from the Guralp Spec Sheet, and the Black comes from the noise test that Rana and I did the other day with the Ranger (elog 2223).  

I'm not really happy with the black spectra - it looks way too high.  I'm still investigating to see if this is a problem with my calibration/method....

I've opened the AP table and I'm working on it.

I re-aligned the Faraday on the AP table. I also aligned the beam to the periscope on the PSL and all the other optics along the beam path.  Now I have a nice NPRO beam at the PLL which overlaps with the PSL beam. The alignment has to be further improved because I see no beat yet.

I wonder if the all the tinkering on the PSL laser done recently to revive the power has changed the PSL NPRO temperature and so its frequency. That could also explain why the beat doesn't show up at the same temperature of the NPRO as I used to operate it. Although I scanned the NPRO temperature +/- 2 deg and didn't see the beat. So maybe the misalignment is the casue.

Not feeling very well right now. I need to go home for a while.

AP table closed at the moment.

NPRO shutter closed

 We definitely changed the PSL NPRO temp while fiddling around, trying to increase the laser power.  I think it's noted in the elog both times that it's happened in the last few months (once when Rana, Koji and I worked on it, and then again when it was just Koji), but we opened up the side of the MOPA box so that we could get at (and change) the potentiometer which adjusts the NPRO temp.  So you may have to search around for a while.

Yes it did.

For long time, the crystal temperature C1:PSL-126MOPA_LTMP was 43~46deg. Now it is 34deg. Try ~10deg lower temperature.

The .mdl code for the mdc and mdp development modules is finished.  These modules need more filters, and testing.  Probably the most interesting piece left to do is putting in the gains and filters for the oplev model in mdp.  It might be OK to simply ignore oplevs and first test damping of the real optic without them.   However, it shouldn't be hard to get decent numbers for oplevs, add them to the mdp (plant) module, and make sure the mdc/mdp pair is stable.  In mdp, the oplev path starts with the SUSPIT and SUSYAW signals. Kakeru recently completed calibration of the oplevs from oplev cts to radians:   1403  .  From this work we should find the conversion factors from PIT and YAW to oplev counts, without making any new measurements.  (The measurements wouldn't be hard either, if we can't simply pull numbers from a document.)  These factors can be added to mdp as appropriate gains.

I've also copied mdc to a new module, which I've named "sas" to address fears of channel name collisions in the short term, and replaced the cpu-to-cpu connections with ADC and DAC connections.  sas can be the guy for the phase I ETMY test.  When we're happy with mdc/mdp, we hopefully can take the mdc filter file from chans, replace all the "MDC" strings with "SAS", and use it.