40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log, Page 251 of 344  Not logged in ELOG logo
ID Date Author Type Categoryup Subject
  7223   Sat Aug 18 01:40:09 2012 MashaConfigurationPEMOnline Seismic Noise Classification Widget

I added a widget to the C1PEM_OVERVIEW MEDM screen. The screen shows the nine seismometer channels (GUR1, GUR2, and STS1 X, Y, and Z), the current signal class in dark red, and the overall confidence in the classification, as Rana suggested. The confidence indication thresholds range from 0.1 to 0.9, in intervals of 0.1. Basically, if a signal class is completely dark red, and the other two classes show only white, or, better yet, nothing at all, this means that we have a clear classification. If, however, the other regions have some yellow, or even red indicators, this means that we are not very confident in our signal classification.

Classification_Widget.png

This is a screenshot of the widget. The nine seismometer channels are classifying the signal as quiet, which is good both because it's the middle of the night, and because the nine seismometer signals somehow agree (I'd use the word correspond with one another, but that implies a strong level of coherence..). The confidence is high, seeing as there's little indication in the truck and earthquake regions (none whatsoever in the truck, meaning that the signal, given our classification method, could not possibly be a truck, and some in the earthquake region (below 0.1 of the quiet signal classification strength, however), possibly due to low seismic disturbance).

  7226   Sat Aug 18 19:29:56 2012 DenUpdatePEMEM 172 microphones noise

I've put EM 172 microphones inside Steve's isolation box to measure their noise. I've attached mics to each other and aligned them using the tape.

At low frequencies (below 1 Hz) the noise is limited by ADC as there is a 10 Hz high-pass filter inside mic readout box.

ADC noise is measured by splitting the signal from 1 mic into 2 ADC channels.

em172.png

  7228   Sun Aug 19 00:54:07 2012 MashaUpdatePEMADC channel switch, triangulation script

Since the classification finally works (or seems to work..), I wrote triangulation scripts in Python which triangulate the signals, and a plotting script in Matlab which generates a heat map of seismic noise source locations. I switched the ADC Streckeisen and Trillium connections in order to better triangulate with the current channels, and will return them either tomorrow, or when I come back from Livingston so that we can have weekday data as well.

  7229   Sun Aug 19 01:41:27 2012 MashaUpdatePEMEarthquake Classified

There was a 5.6 Earthquake that occurred near Tofino, Canada about 30 minutes ago. It showed up rather strongly on the BLRMS.

The neural network classification system also picked up on it, but oscillated from Earthquake (1.0) to Quiet (0.5) perhaps due to the filters we currently have installed. Here is a shot of the GUR1X classification channel at the time of the EQ:

 Earthquake_Found.png

  7244   Tue Aug 21 15:26:04 2012 SteveUpdatePEMtemp sensor for vacuum

Temperature sensor for vacuum. How many : 2 or 3 ?  $350 each

Glass encapsulated thermistor #55007  with Ceramabond 835-m glued onto spade connector and hooked up to controller DP25-TH-A with analoge output.

This zero to 10Vdc can go to ADC

  7251   Wed Aug 22 18:58:12 2012 JenneUpdatePEMWeird BLRMS increase

It seems as though there is something funny going on around ~1.5 Hz, starting a little over an hour ago.

We see it in the BLRMS channels, the raw seismometer time series, as well as in various suspensions and LSC control signals.  It's also pretty easy to see on the camera views of all the spots (MC, arms, transmissions....AS is a little harder to tell since it's flashing, but it's there too).

The plots I'm attaching are only for ~10min after the jump happened, but there has been no change in the BLRMS since it started.  Usually, we'd see an earthquake in all the channels, and even big ones ring down after a little while.  This is concentrated at a pretty narrow frequency (some of Den's plots for later have this peak), and it's not ringing down, so it's not clear what is going on.

Here is a whole pile of plots.  Recall that the T-240 is plugged into the "STS_3" channels, and we don't have BLRMS for it, so you can look at the time series, but not any frequency specific stuff.

  7253   Thu Aug 23 00:18:54 2012 JenneUpdatePEMWeird BLRMS increase
While I was gone for dinner break, the BLRMS went back to normal. Then, almost 2 hours later, another peak appeared, this time closer to 1Hz. Den noticed that it was hard to maintain any lock, since the optics were ringing up so much.

The MC was moving pretty significantly, and just to check, I turned off the WFS for a moment. The MC transmitted power was fluctuating by almost 50% until I turned the WFS back on.

Attached is a spectrum of the BS OSEM sensors. The higher frequency peak around 1.65Hz is from the time I posted the time series about earlier. The lower frequency peak around 1.15Hz is from the second interval of noise.

Now, the noise is gone, and things are back to normal (for now....)
  7254   Thu Aug 23 10:08:13 2012 SteveUpdatePEMseismometers?

Quote:

It seems as though there is something funny going on around ~1.5 Hz, starting a little over an hour ago.

We see it in the BLRMS channels, the raw seismometer time series, as well as in various suspensions and LSC control signals.  It's also pretty easy to see on the camera views of all the spots (MC, arms, transmissions....AS is a little harder to tell since it's flashing, but it's there too).

The plots I'm attaching are only for ~10min after the jump happened, but there has been no change in the BLRMS since it started.  Usually, we'd see an earthquake in all the channels, and even big ones ring down after a little while.  This is concentrated at a pretty narrow frequency (some of Den's plots for later have this peak), and it's not ringing down, so it's not clear what is going on.

Here is a whole pile of plots.  Recall that the T-240 is plugged into the "STS_3" channels, and we don't have BLRMS for it, so you can look at the time series, but not any frequency specific stuff.

Atm1,  I'm not sure about the seismic data.   Baja earthquake magnitude 3.0 at  yesterday morning.Seismometers do not see them !

Atm2,  No posted seismic activity.  Someone is jump walking in the lab? Why are there time delays between the suspensions?

  7262   Thu Aug 23 21:53:18 2012 YaakovUpdatePEMAccelerometer location

The MC1 accelerometer cube (3 accelerometers arranged in x,y,z) is under the PSL table, as I found it at the beginning of the summer.

The MC2 accelerometer cube is on the table where I worked on the STACIS, right when you walk into the lab from the main entrance. Their cables are dangling near the end of the mode cleaner, so the accelerometers are ready to be placed there if wanted.

All accelerometers are also plugged into their ADC channels.

  7269   Fri Aug 24 11:46:59 2012 MashaUpdatePEMNew classification weights

I recently realized that I may have over-trained my classification neural network and used too many parameters, so that my weight vectors are too fine-tuned to my particular data set and do not generalize well. I lowered the number of hidden neurons in the network to 15, and the number of epochs to 25000, and regularized based on the deltas (the gradient). Here is the most recent learning curve:

 

current_learning_curve.png

 

 

The old weights and code are saved in the c1pem directory in the file "classify_seismic_20neurons.c", while the current 15 neuron network is saved as "classify_seismic.c". I'll monitor the performance of this current network throughout the day, and decide which one we should keep.

  7281   Mon Aug 27 08:34:18 2012 SteveUpdatePEMearthquakes

Shasky day yesterday postpones venting. We had about 11 shakes larger than mag 4.0 Mag5.5 was the largest at  13:58 Sunday, Aug 26 at  the Salton Sea area.

Atm3,  ITMX and ETMX  did not come back to it's position

  7373   Wed Sep 12 08:16:49 2012 SteveConfigurationPEMchamber must be sealed overnight!

Quote:

We conducted a beam scan on the AP table of the AS beam. We used a lens to focus the beam onto a power meter, and slowly moved a razor blade across the beam using a micrometer, vertically and horizontally both in front of and behind the beam. We also had to block the beam next to the AS beam in order to do this, but is unblocked now. Mike will begin curve fitting the data to try and see if there is a different spot size given by the x-axis vs. the y-axis, and if the lens has any effect.

 The vacuum envelope must be sealed with light doors on o-rings to insure a bug free IFO.  This was a violation!

  7392   Fri Sep 14 21:03:02 2012 DenUpdatePEMBS and AS tables

I've measured seismic and acoustic noise on BS and AS tables. It seems that horizontal motion of BS table is ~1.5-2 times more then AS table in the frequency range 5-50 Hz.

Edit by Den: this was POI table, not BS!

vert.png  horiz_4_50.png

acoustic.png      coh.png

  7394   Sat Sep 15 18:46:50 2012 DenUpdatePEMmicrophone location

I've suspended microphones around the lab

C1:PEM-MIC_1 - MC2
C1:PEM-MIC_2 - ETMX
C1:PEM-MIC_3 - PSL
C1:PEM-MIC_4 - AS
C1:PEM-MIC_5 - POI
C1:PEM-MIC_6 - ETMY

mics.png

  7395   Sat Sep 15 20:27:54 2012 DenUpdatePEMBS and AS tables

Quote:

I've measured seismic and acoustic noise on BS and AS tables. It seems that horizontal motion of BS table is ~1.5-2 times more then AS table in the frequency range 5-50 Hz.

Edit by Den: this was POI table, not BS!

 This seismic measurement is for BS and AS tables.

bs_as_h.jpg       bs_as_v.jpg

  7396   Mon Sep 17 07:57:58 2012 ranaUpdatePEMBS and AS tables for REFL change

 

 This was in response to my suggestion to move the REFL beam path to the table containing the BS/PRM Oplevs. From this seismic data it is clear that the BS table is no worse than the AS table, so we should plan to make the layout change during the next vent.

  7429   Sat Sep 22 01:03:30 2012 DenUpdatePEMETMY table

I've installed Guralp readout box back and it turned out that it does not work with voltage provided from the rack (+13.76 0 -14.94).  +/-12 voltage regulators inside the box convert it to -0.9 0 -12. I've connected the box to +/-15 DC voltage supply to measure seismic motion at the ETMY table. Readout box works fine with +/- 15.

Seismic noise on the ETMY table measured to be a few times higher then on the floor in horizontal direction in the frequency range 50 - 200 Hz. Attached are compared spectrums of X, Y and Z motions.

  7433   Mon Sep 24 17:03:39 2012 JenneUpdatePEM1X1 rack power

Quote:

I've installed Guralp readout box back and it turned out that it does not work with voltage provided from the rack (+13.76 0 -14.94).  +/-12 voltage regulators inside the box convert it to -0.9 0 -12. I've connected the box to +/-15 DC voltage supply to measure seismic motion at the ETMY table. Readout box works fine with +/- 15.

 I'm not sure what the problem is here.  Den and I looked at it for a few minutes, before I went back to helping with putting doors on.  The Sorensons are not supplying the rack power for 1X1.  There are some flat cables which go from the fuses on the side of the rack up to the cable tray, and go elsewhere.  Den is going to continue looking into this, but I think it's a moderately high priority, since lots of things should be getting served by that same power.

  7459   Mon Oct 1 19:21:03 2012 ranaConfigurationPEMchanged PEM DQ channels

Changed the list of channels to be written to frames from having the IN1 suffix to OUT. Now we can load the calibration of the channel into the filter module and the DQ channel will be calibrated.

We should do this wherever possible so that our channels will have real calibrations associated with them.
SEIS_GUR1_X_OUT 256
SEIS_GUR1_Y_OUT 256
SEIS_GUR1_Z_OUT 256
SEIS_GUR2_X_OUT 256
SEIS_GUR2_Y_OUT 256
SEIS_GUR2_Z_OUT 256
SEIS_STS_1_X_OUT 256
SEIS_STS_1_Y_OUT 256
SEIS_STS_1_Z_OUT 256
SEIS_STS_2_X_OUT 256
SEIS_STS_2_Y_OUT 256
SEIS_STS_2_Z_OUT 256
SEIS_STS_3_X_OUT 256
SEIS_STS_3_Y_OUT 256
SEIS_STS_3_Z_OUT 256
MIC_1_OUT 2048
MIC_2_OUT 2048
MIC_3_OUT 2048
MIC_4_OUT 2048
MIC_5_OUT 2048
MIC_6_OUT 2048
ACC_MC1_X_OUT 2048
ACC_MC1_Y_OUT 2048
ACC_MC1_Z_OUT 2048
ACC_MC2_X_OUT 2048
ACC_MC2_Y_OUT 2048
ACC_MC2_Z_OUT 2048
XARM_DIFFERENTIAL_MOTION_IN1 256
XARM_DIFFERENTIAL_MOTION_OUT 256
YARM_DIFFERENTIAL_MOTION_IN1 256
YARM_DIFFERENTIAL_MOTION_OUT 256

Next we should up the rate at which the model runs up to 16 kHz so that we can record the microphones at 16 kHz. FM radio has information up to 20 kHz. AM radio goes up to ~8 kHz. We should be at least as modern as AM radio. How do we make the change? How do we make sure the FOTON file stays OK?

I have made some changes to the daily summary file to compensate. New files is /users/public_html/40m-summary/share/c1_summary_page.ini.

  7468   Wed Oct 3 15:37:04 2012 SteveUpdatePEMants on the PSL table

We observed one or two ants climbing over PMC optics without booties and safety glasses.

The floor was mopped with strong Bayer Home Pest Control solution in the Vertex area.

Do not work inside the 40m lab if you are sensitive to chemicals!

 

  7470   Wed Oct 3 16:26:58 2012 ManasaUpdatePEMants on the PSL table

I spotted around 4 within 30 minutes working at the PSL table even after the deathly spray. They seem to be running down from the cables on the oscilloscope rack to the table and the optics.

  7487   Fri Oct 5 00:29:34 2012 DenUpdatePEMreadout box power

Guralp readout box received +13.7 /0/ -15V instead +15V because of the broken fuse. Power provided by the source is normal.

Edit by Den: I've found a similar fuse on one of the tables and borrowed it. Guralp is not working again.

  7488   Fri Oct 5 01:36:49 2012 DenConfigurationPEMchanged PEM DQ channels

Quote:

We should do this wherever possible so that our channels will have real calibrations associated with them.

Next we should up the rate at which the model runs up to 16 kHz so that we can record the microphones at 16 kHz. FM radio has information up to 20 kHz. AM radio goes up to ~8 kHz. We should be at least as modern as AM radio. How do we make the change? How do we make sure the FOTON file stays OK?

 I've added calibration gains to Guralp (to um/sec) and EM172 (to Pa) channels.

We can run PEM at 16 kHz. I think Foton file stores both sos-representation and filter commands which are independent of the sampling frequency, so it should be possible to change model sampling frequency quickly.

In fact, we can save data at 64 kHz from iop models. I've done this once with MC_F channel. However, I did not test EM172 noise at frequencies > 1 kHz.

  7490   Fri Oct 5 11:11:00 2012 DenUpdatePEMreadout box power

Quote:

Guralp readout box received +13.7 /0/ -15V instead +15V because of the broken fuse. Power provided by the source is normal.

Edit by Den: I've found a similar fuse on one of the tables and borrowed it. Guralp is not working again.

 I've meant Guralp is NOW working again 

  7539   Fri Oct 12 22:44:49 2012 DenUpdatePEMETMY table

Quote:

Seismic noise on the ETMY table measured to be a few times higher then on the floor in horizontal direction in the frequency range 50 - 200 Hz. Attached are compared spectrums of X, Y and Z motions.

Accelerometers were installed on the ETMY table and nearby ground to measure amplification of the seismic noise due to the table. During this experiment ground and table motions were measured simultaneously.

DSC_4734.JPG     DSC_4736.JPG

  7540   Sun Oct 14 11:41:42 2012 DenUpdatePEMETMY table

Quote:

 

Accelerometers were installed on the ETMY table and nearby ground to measure amplification of the seismic noise due to the table. During this experiment ground and table motions were measured simultaneously

 I've added xml file with measurement settings and data to 40m svn at directory 40m_seismic/etmy.

DSC_4739.JPG 

  7541   Sun Oct 14 16:44:20 2012 DenUpdatePEMETMX table

 I've measured ETMX table motion compared to ground motion using accelerometers. Data and settings in the xml file are at the svn directory 40m_seismic/etmx.

DSC_4742.jpg

  7542   Sun Oct 14 17:26:03 2012 DenUpdatePEMETMX table

Quote:

 I've measured ETMX table motion compared to ground motion using accelerometers. Data and settings in the xml file are at the svn directory 40m_seismic/etmx

 High frequency (>60 Hz) resonances that are present at the ETMX motion spectrum seem to be understandable. Amplification ETMX/GROUND of a factor of 2 at 1 Hz is interesting. I've monitored ACC DQ channels for a few hours and noticed that usually spectrum looks like in the previous elog. But every ~40 min ETMX motion is much higher then ground motion at low frequencies (<5 Hz). I wonder if this a reaction of a table to outside disturbances or accelerometer issue.

 

  7543   Sun Oct 14 20:51:20 2012 DenUpdatePEMAA board

Quote:

 

 But every ~40 min ETMX motion is much higher then ground motion at low frequencies (<5 Hz). I wonder if this a reaction of a table to outside disturbances or accelerometer issue. 

 This could come from AA board, its range is +/- 2.5 V, RMS of the ETMX table motion is a few times higher then ground motion, so ETMX accelerometer signal was corrupted.

acc.png

As this small AA range has already caused problems before, I decided to increase it. I've looked through the board scheme and found that all its differential line receives and output amplifiers have absolute maximum range of 40V. We used KEPKO power supply for this board with a voltage range up to 6 V. So I've replaced it with a BK PRECISION power supply and set it to +/- 15 V. Now AA board range is 7.5 V.

DSC_4747.JPG 

I'll leave accelerometers near ETMX table. It's interesting to measure table motion in the morning when trucks drive by.

  7546   Mon Oct 15 10:14:22 2012 DenUpdatePEMAA board

Quote:

 

 I'll leave accelerometers near ETMX table. It's interesting to measure table motion in the morning when trucks drive by.

 That low frequency effect was due to AA board, now it is gone.

  7562   Tue Oct 16 21:57:47 2012 DenUpdatePEMaccelerometers

All accelerometers are now at the table behind 1X4, cables are near readout box.

  7567   Wed Oct 17 09:01:37 2012 SteveUpdatePEMants on the PSL table

Quote:

We observed one or two ants climbing over PMC optics without booties and safety glasses.

The floor was mopped with strong Bayer Home Pest Control solution in the Vertex area.

Do not work inside the 40m lab if you are sensitive to chemicals!

 

 The floor is mopped again with strong PEST CONTROL SOLUTION in water in the Vertex area.

Do not plane to work in the IFO-room till noon if you are sensitive to chemicals!

  7626   Thu Oct 25 21:02:34 2012 DenUpdatePEM1x7 dc power

 We now stop using bench DC power supplies for microphone preamp and PEM AA board. DC power is wired from 1x5 rack suppliers. I've installed a beam to mount fuse houses in the 1x7 as we did not have one.

DSC_4779.JPG

  7645   Wed Oct 31 14:31:34 2012 SteveUpdatePEMhigh particle count

High particle count confirmed with #2 counter

  7650   Wed Oct 31 22:56:41 2012 DenUpdatePEMacoustic noise

Microphone preamp box had a low-pass filter at 2kHz, Ayaka changed it to 20 kHz by replacing 100pF capacitor with a 10pF.

We've measured frequency response of the box. Signal from the microphone was split into two. One path went to the box, while another was amplified by the gain 20 (and bandpass filter 1Hz - 300kHz) and sent to spectrum analyzer. Coherence and frequency response were measured using box output and amplified input. Low-pass filter in the box does not limit our sensitivity.

Acoustic noise significantly decreases at frequencies higher then 2kHz. So we need to modify the circuit by adding whitening filter.

pre_after_mic.png  freq_resp.png

I've plugged in PMC length channel into PEM board CH15 through and amplifier (gain=200) that is AC coupled to avoid ~2.5 DC V coming from PMC servo.  I measured coherence with microphone that was located ~30 cm higher. Measurements show contribution of acoustic noise to PMC length in the frequency range 20-50 Hz. In this range PMC length / MC length coherence is ~0.5.

Acoustic noise couples to PMC length in a non-stationary way. 5 minutes after the first measurement I already see much higher contribution. This was already discussed here. I've made C1:X02-MADC3_TP_CH15 a DQ channel at 64kHz. This a fast PMC length channel.

Next step will be to use several microphones located around PMC for acoustic noise cancellation.

DSC_4792.JPG    DSC_4793.JPG

  7680   Wed Nov 7 11:43:29 2012 SteveUpdatePEMhigh particle count ALART

The BS camber is open only. We should close ASAP

Outside air quality is 1.7- 2.2  million particles  / cf min of 0.5 micron

  7681   Wed Nov 7 14:59:35 2012 SteveUpdatePEMhigh particle count ALART & oplevs

Quote:

The BS camber is open only. We should close ASAP

Outside air quality is 1.7- 2.2  million particles  / cf min of 0.5 micron

 Air is still bad and the chambers are closed. Before lunch  Jamie repointed the PRM oplev. Manasa and I reset oplevs: BS and ITMX.

ETMX and ETMY are fine.

SRM and ITMY oplevs needs more work.

  7733   Tue Nov 20 15:24:52 2012 AyakaUpdatePEMSeismometers and a microphone

 I got two seismometers and one microphone back from Tara.

They are now near the Gurlap under the MC.

  7734   Tue Nov 20 16:03:37 2012 janoschUpdatePEMSeismometers and a microphone

Quote:

 I got two seismometers and one microphone back from Tara.

They are now near the Gurlap under the MC.

 If anybody wants a fancy single-axis seismometer for a while (GS-13), then please let me know.

  7744   Mon Nov 26 10:58:20 2012 SteveUpdatePEMair cond maitenance tomorrow

Air conditioning maintenance is scheduled for tomorrow morning till noon.

  7745   Mon Nov 26 18:36:17 2012 JenneUpdatePEMBLRMS back

Quote:

 I got two seismometers and one microphone back from Tara.

They are now near the Gurlap under the MC.

 I have finally plugged GUR1 back in....it is down at ETMY for now, since that's where the cable was.  BLRMS are back up on the projector.

  7754   Tue Nov 27 11:27:22 2012 SteveUpdatePEMparticle count is going up

Jeff is still working on the filter banks.
  7759   Wed Nov 28 23:18:35 2012 CharlesUpdatePEMDecreased RMS in Seismometers

The attached plots display RMS noise from various accelerometers and seismometers over the past 90 days. One can see how after the reinstallation of the seismometers in November, RMS from the GUR1Z and GUR1X channels decreases by a factor of about 100 from data in August. Additionally, the RMS over the course of the last 90 days has notably decreased in all instruments. In many cases, the RMS is only the result of inherent electronics noise, rather than from a signal.

  7762   Thu Nov 29 02:43:48 2012 AyakaUpdatePEMDecreased RMS in Seismometers

Quote:

The attached plots display RMS noise from various accelerometers and seismometers over the past 90 days. One can see how after the reinstallation of the seismometers in November, RMS from the GUR1Z and GUR1X channels decreases by a factor of about 100 from data in August. Additionally, the RMS over the course of the last 90 days has notably decreased in all instruments. In many cases, the RMS is only the result of inherent electronics noise, rather than from a signal.

The Image is replaced

[Den, Ayaka]

We found that seismometer was working and the calibration in the filter banks should have been wrong.
We turned off the all FM2 filter in RMS filter banks.

We also installed STS seismometer. It is under the BS. Now we have spectrum of three seismometers.
GUR1Xfilterbank.pngseismometers1129.pdf


 

RA: the above plot is kind of unreadable and useless. Please replace with something legible and put in some words about why there is a wrong filter, what exactly it is, etc., etc. etc. And why would you leave in a filter which is not supposed to be on? We might as well leave a few secretly broken chairs in the control room...

  7763   Thu Nov 29 09:58:06 2012 DenUpdatePEMDecreased RMS in Seismometers

Quote:

[Den, Ayaka]

We found that seismometer was working and the calibration in the filter banks should have been wrong.
We turned off the all FM2 filter in RMS filter banks.
 

We also installed STS seismometer. It is under the BS. Now we have spectrum of three seismometers;
 

RA: the above plot is kind of unreadable and useless. Please replace with something legible and put in some words about why there is a wrong filter, what exactly it is, etc., etc. etc. And why would you leave in a filter which is not supposed to be on? We might as well leave a few secretly broken chairs in the control room...

 First of all, STS-2 is in the end of X arm, GUR2 is under BS, GUR1 is in the end of Y arm.

BLRMS were small because we applied calibration from counts to um/s two times. In the past we had calibration in the RMS BP filter bank (vel2vel = FM2). Now we have calibration in the seismometer input filter bank so we can save calibrated _OUT channels.

  7777   Mon Dec 3 16:37:09 2012 SteveUpdatePEMEM 172 microphones ordered

Quote:

I've put EM 172 microphones inside Steve's isolation box to measure their noise. I've attached mics to each other and aligned them using the tape.

At low frequencies (below 1 Hz) the noise is limited by ADC as there is a 10 Hz high-pass filter inside mic readout box.

ADC noise is measured by splitting the signal from 1 mic into 2 ADC channels.

em172.png

 BT EM172 microphones  are ordered.

  7780   Tue Dec 4 10:44:36 2012 SteveUpdatePEMshort power outage

 

CALIFORNIA INSTITUTE OF TECHNOLOGY

                 FACILITIES MANAGEMENT

 

**PLEASE POST**

 

 

Building:         Campus

 

Date:             Thursday October 04,2012

 

This morning at 2:17 a.m. much of the City of Pasadena including our Campus experienced a electric power sag of short duration, approximately 1/10 of a second. The cause was a fault on one of Pasadena’s 17KV circuits. Some sensitive equipment have been impacted.

                 

Contact:          Mike Anchondo x-4999

  7807   Tue Dec 11 08:53:52 2012 SteveHowToPEMcables needs care

How NOT to:

The janitor can not clean in areas like this. He may only steps on these cables accidentally as he dust wiping our chambers.

  7809   Tue Dec 11 10:09:04 2012 AyakaHowToPEMcables needs care

Quote:

How NOT to:

The janitor can not clean in areas like this. He may only steps on these cables accidentally as he dust wiping our chambers.

 Sorry for the mess. I fixed it.

  7819   Thu Dec 13 01:49:53 2012 ranaUpdatePEMseismometers

Quote:

I've installed Guralp readout box back and it turned out that it does not work with voltage provided from the rack (+13.76 0 -14.94).  +/-12 voltage regulators inside the box convert it to -0.9 0 -12. I've connected the box to +/-15 DC voltage supply to measure seismic motion at the ETMY table. Readout box works fine with +/- 15.

Seismic noise on the ETMY table measured to be a few times higher then on the floor in horizontal direction in the frequency range 50 - 200 Hz. Attached are compared spectrums of X, Y and Z motions.

 Looking at the PEM BLRMS, I noticed that the GUR1Z channel had a much reduced microseism compared to the GUR1X. Looking at the BLRMS screens everything seems ON, although its a mess (too many filters in the banks, etc. - clean this up, PEM people).

 Looking at the Z channel in DTT, I see that the Z spectra looks double high pass filtered below ~1 Hz.     Needs some attention in the daytime.

From Den and Ayaka's elog entry from Nov 29, its clear that this problem is there at that time. It seems that the seismometer was not even hooked up before then. Perhaps Tara returned the seismometer around Thanksgiving and then someone here hooked it up but neglected to log this work? If so, please make an elog now describing the installation of this sensor at the 40m and log any future work which takes place at the 40m lab even if you think it is inconsequential.

ELOG V3.1.3-