Displaying reports 56101-56120 of 83004.Go to page Start 2802 2803 2804 2805 2806 2807 2808 2809 2810 End
Reports until 19:21, Wednesday 08 June 2016
H1 SEI (CDS, SEI)
krishna.venkateswara@LIGO.ORG - posted 19:21, Wednesday 08 June 2016 - last comment - 10:32, Thursday 09 June 2016(27656)
BRSX Damper Upgrade in Progress

Michael, Krishna

We made a lot of progress on the BRSX upgrades today.

The new belt driven turntable was installed which is designed to have less vibrations during damping. The previous turntable used gears and a loud stepper motor which caused vibrations which in turn drove up modes of the balance. (see 26265) The new turntable uses a belt and a much quieter Bekchoff stepper motor which has noticably less vibrations. Also, the Mightex camera, a 2048 pixel CCD read over USB, was replaced with a Basler camera which has 4096 pixels and is read over ethernet. This new camera will remove the USB communication error which was causing the system to crash every couple weeks.

Additionally, we replaced the laptop and NI DAQ card with a Beckhoff computer and electronics. Both the C# code, which turns images into angles, and the PLC code, which controls the damper and sends data out, are working and data is being sent out to the seismic front ends. However, the EPICS communication has yet to be set up so many of the diagnostic channels are not being read.

The balance is rung up to a very large amplitude due to the work today but we've begun to slowly damp it down with the new turntable.

Comments related to this report
michael.ross@LIGO.ORG - 10:32, Thursday 09 June 2016 (27665)SEI

Here are some pictures of the damper before and after the upgrade. The first one shows the old turn table in the bottom left under the arm and the Mightex camera wrapped in foil on the very top of the autocollimator. The second one show the old stepper motor and gears. The third shows the new turn table on the left, the new electronics box in front of the chamber, and the new Basler camera and mount on the top. The third is more detailed view of the turntable with the new stepper motor in the back and the drive belt running below the damping masses.

Also attached is a video showing the smooth motion of the damper. This was while the balance was rung up so the damper is moving from the counter-clockwise limit in beginning of the video to almost the clockwise limit about two thirds through.

Images attached to this comment
Non-image files attached to this comment
H1 PSL
jeffrey.bartlett@LIGO.ORG - posted 16:18, Wednesday 08 June 2016 (27655)
Change PSL In-Line Filters
   During the power outage recovery,(06/06/2016) took the opportunity to replace the PSL in-line coolant filters. 

   The first set of filters are located in the Chiller Room on the discharge side of the chiller. There was some debris in the bottom of the Crystal Chiller filter. There was significantly less debris in the bottom of the Diode Chiller filter. There was little difference in the discoloration between the two filters in the Chiller room. After 31K hours of operations these filters are in very good condition. 

   The second set of filters are located in the PSL enclosure on the intake side of the cooling system manifold block. There was very small amount of debris in the bottom of the Crystal chiller filter. There was no noticeable debris in the Diode chiller filter. There was no noticeable difference in discoloration between these two filters. As expected, these filters were not as discolored as the filters in the Chiller Room. 

   In general, the PSL filtration appears to be working very well. In the future, these filter will be replaced at the same time the primary and backup chillers are swapped (planned for once a year). 

   I am working on getting a local lab to analyze the debris from the Cristal chiller. When we know what all this material is, we can make a better informed decision as to the internals of the PSL cooling system.           
Images attached to this report
H1 SUS
nutsinee.kijbunchoo@LIGO.ORG - posted 16:15, Wednesday 08 June 2016 - last comment - 18:24, Monday 13 June 2016(27654)
Damp setting for violin mode 505.710

ETMX Mode3: FM1, FM2, FM4,  +10 gain (BP, -60deg, 100dB) seems to have worked quite well. No need to turn on a damping for 505.707 (which should be checked again with 0.0001 BW to see if it's really exists). 505.707 should be watched while damping 505.710 just in case.

The new violin mode table is being uplated slowly. The modes with Damp Setting column filled out are the one that's been sucessfully damped by the filter settings indicated in the table.

Comments related to this report
sheila.dwyer@LIGO.ORG - 01:07, Thursday 09 June 2016 (27660)

Jenne, Sheila

With the long lock tonight we got to do some more violin damping.  I haven't updated the wiki or guardian.

At first we thought the largest mode was the 505.71 mode that Nutsinee logged about, and tried to damp it without sucsess using the settings she described.   After getting a 0.002 Hz spectrum we could see that it was really 505.706Hz. (on the wiki there is a note asking if this mode really exists, looks like it does) I tried to damp this with ETMX MODE 2, which has a narrower filter, and in the last 5 minutes of the lock it looked like a phase of -60 and gain of 30 was working, with the 505.71 notch engaged, but we unlocked before we could be really sure it was working.

We damped the mode at 506.922 (ETMX mode5) using a phase of 0 degrees and a gain of 30.  FM1 and FM4.  (This is different from what is on the old wiki)  the new wiki has this mode not damped.

We also damped a 500.062Hz mode (ITMX mode 1, 0 degrees gain +30, also different from the wiki)  With higher gain and the same filter settings we rang the mode up.

The top panel shows the fundamental violin mode forest at the begining of the lock in blue, and the end in red.  (There is a tiny improvement in 505.707Hz)  The bottom panel shows the 0.002 Hz spectrum with cursors at 505.71 and 505.707Hz.

Images attached to this comment
evan.hall@LIGO.ORG - 01:22, Saturday 11 June 2016 (27697)

A negative gain for the 505.707 mode worked for me (although it's not clear whether it damped 505.707 or 505.710).

nutsinee.kijbunchoo@LIGO.ORG - 18:24, Monday 13 June 2016 (27713)

The setting I had seems to work on both 505.707 and 505.71.

Images attached to this comment
H1 General
nutsinee.kijbunchoo@LIGO.ORG - posted 15:56, Wednesday 08 June 2016 (27653)
Ops Day Shift Summary

Morning Meeting

- ER9 in a month

- Extended maintenance is cutting in commissioning time. Try to not do it on Mon,Wed, Fri

SEI: No issue on recivering

CDS: "Fine"

Software: Don't assume things are perfect (due to the recovery from scratch).

FAC: Facility assessment tomorrow


Activities (All time in UTC)

~15:30 Fil to EX

16:00 Kristina to MX, Karen to MY

16:48: Robert setting up stuff by PSL

17:00 Robert out

18:04 Karen leaving MY

18:20 Betsy to LVEA

18:30 Betsy out

19:20 Fil back

~19:30 dave to Mid stations

20:00 Dave back

20:05 Betsy to optics lab

20:20 Fil to EX outside VEA (pulling cables)

21:01 Kyle to CP3 overfill

          Patrick, Krishna, Michael, Dave, Jim to EX to install BRS Beckhoff comp.

21:29 Kyle back

21:55 Dave+Jim back

22:07 Patric+Fil back

22:10 Fill dropping stuff at EX

H1 IOO (IOO, SUS)
cheryl.vorvick@LIGO.ORG - posted 14:51, Wednesday 08 June 2016 (27651)
IM2 and IM3 show signs of dissipating charge after ISI trip

Drift over 3+ hours:

Images attached to this report
Non-image files attached to this report
LHO VE
kyle.ryan@LIGO.ORG - posted 14:38, Wednesday 08 June 2016 (27652)
Manually over-filled CP3
1410 - 1425 hrs. local -> To and from Y-mid 

Opened exhaust check valve bypass, opened LLCV bypass valve 1/2 turn -> LN2 at exhaust after 4 minutes and 40 seconds -> Restored valves to as found -> Increase CP3 LLCV manual %open from 19% to 20%.  

Next manual overfill to be Friday, June 10th.
H1 ISC (ISC, SUS)
rich.abbott@LIGO.ORG - posted 11:41, Wednesday 08 June 2016 - last comment - 11:16, Thursday 09 June 2016(27650)
Oscillation on ETMX ESD Driver
Terra, Carl B., Rich

Terra and Carl had noticed a ~20mVp-p 1.3MHz oscillation on the ETMX ESD Driver at viewed with an oscilloscope at the output (SHV connectors on the front panel) leading to the ETM.  After confirming that the oscillation was really generated by the ESD Driver, Carl and I opened the spare to see if we could find a set of conditions that might produce such an oscillation.  By examining the spare, we were able to trace the potential instability to the first stage of the two stage pole-zero dewhitening filter.  Poking at this stage with my finger will occasionally get it to latch into the 1.3MHz oscillation state.  We drove the output of the opamp in question with a 1vp-p, 1kHz square wave through 400 ohms to get a better feel for the dampling and phase margin under normal operating conditions.  This stage is completely stable with the pole-zero stage engaged, but becomes marginally stable with the pole-zero stage bypassed.  The problem can be cured by the addition of a small (~30pf) capacitor across the feedback 21kohm resistor implying it is worsened by input capacitance.

We opted not to pull all the drivers and fix this problem.  The reasoning is that this stage is in its stable state (pole-zero engaged) while the driver is used as a low noise driver for length control of the ETM.  There is really no driving need to fix this at this point, but we wanted to document its existence for optional repair at a later date.  A fault report will be written to further document the issue.  
Comments related to this report
rich.abbott@LIGO.ORG - 11:16, Thursday 09 June 2016 (27666)
Added to FRS https://services.ligo-la.caltech.edu/FRS/show_bug.cgi?id=5675
H1 SEI
hugh.radkins@LIGO.ORG - posted 10:12, Wednesday 08 June 2016 - last comment - 08:32, Thursday 09 June 2016(27648)
H1 ITMX ISI Stage1 V1 CPS Still Noisy

As I reported in 27622, the elevated noise is still present in the Stage1 V1 CPS of the ITMX.  We should try a power cycle of the chassis at earliest opportunity.  I don't have access to DetChar at the moment to see if this noise is impacting the ISI performance.

Comments related to this report
richard.mittleman@LIGO.ORG - 07:41, Thursday 09 June 2016 (27662)

 It is very likely that a noisy vertical sensor will create excess noise in the horizontal direction, particularly if the 45mhz blends are being used

 I'm going to guess that a power cycle isn't going to help, I would consider swapping the electronics

hugh.radkins@LIGO.ORG - 08:32, Thursday 09 June 2016 (27663)

But Rich,  If you look at the history in the plots and words, you see that this type of noise has come and gone.  The noise on this channel wasn't there before the power outage cycle and the others that were present have gone away.

H1 IOO (IOO, SUS)
cheryl.vorvick@LIGO.ORG - posted 06:59, Wednesday 08 June 2016 (27646)
IM1-4 alignment shift investigation - data suggesting IM1-3 are suffering a mechanical interference

I have analyzed the IM OSEM signals from the May 19th ISI trip, while both the ISI and the IM optics were tripped, and have injected a step funtion into TEST PIT and TEST  YAW to measure Q values.

 

Power Spectrums:

 

Length signals for IM1-4, and the signal for IM4 shows clean peaks for yaw and it's 1st harmonic and length and it's first harmonic.  All other IMs have peaks that are lower than the peaks in IM4.

 

Q values:

 

I measured the length and yaw Q values for each IM, and my original post is alog 27327.  In that post, I list pitch and yaw, however the resonant frequency I measured that's labeled as pitch is actually length. 

 

IM4 shows the highest Q values for length and yaw, and comparing the Q values for IM1-3, they are all between 54% and 95% of the IM4 Qs.

 

Time Series:

 

The time series of the individual OSEM signals reveals a difference in amplitude in the oscillations of OSEMs, when comparing the four OSEMs on each optic.  

 

I measured the period of oscillations for each OSEM on each IM, and in reality the period was not very enlightening, however, I also collected the oscillation amplitude of each OSEM near the end of the time the optic was tripped.  The oscillation amplitudes proved to be very revealing, and show that the OSEMs on IM4, the IM that has never shown an alignment shift , have very different behavior than the OSEMs on IM1-3, that have all had significant alignment shifts. 

 

 

Details / Summary of power spectrums for IM1-4: attachment 1

 
Details / Summary of Q values:
 
IM1 length 1.21
IM2 length 1.43
IM3 length 1.36
IM4 length 1.50
IM1 yaw 1424
IM2 yaw 1087
IM3 yaw 1270
IM4 yaw 2009

 

Details / Summary of oscillation amplitude data for IM1-4: attachment 2

IM4: no alignment shifts observed in my IM investigation, highest average percent of max oscillation at 94%

IM2: largest and most consistent alignment shifts observed, has the OSEM with the lowest percent of max OSEM oscillation at 70%

IM3: second largest alignment shifts, has the lowest average percent of max oscillation at 81%

IM1: smallest alignment shifts, one OSEM at 92%of max oscillation, others at 76% and 82%

Non-image files attached to this report
H1 General
travis.sadecki@LIGO.ORG - posted 23:57, Tuesday 07 June 2016 - last comment - 09:46, Wednesday 08 June 2016(27644)
Ops Eve Shift Summary

TITLE: 06/08 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
INCOMING OPERATOR: None
SHIFT SUMMARY:  Spent the entire shift getting through Initial Alignment.  Major by-hand alignment required at every step of IA.  Things are still drifting as a result of temperature excursion during power outage.  But we made it . . through IA that is.
LOG:  8 hours of aligning
 

Comments related to this report
evan.hall@LIGO.ORG - 02:13, Wednesday 08 June 2016 (27645)

We were able to engage vertex angular loops and hard arm loops without issue. The soft arm loops pulled the recycling gain up but made the sideband powers drop. This may indicate the PRM pointing loop is fighting the soft loops.

Violin modes are still high (about where they were on Friday) and will need attention if we want to engage DCPD whitening.

sheila.dwyer@LIGO.ORG - 09:46, Wednesday 08 June 2016 (27647)

One of the problems we encountered was that the X arm alignment was so far off when we started that the ITM camera image was clipped on the digital aperature, and the servo appeared to be running but didn't bring the spot to the reference position.  Travis moved the ITM by hand to fix this. 

H1 CDS (DAQ)
david.barker@LIGO.ORG - posted 21:01, Tuesday 07 June 2016 (27643)
CDS maintenance summary

DAQ frame writers

The frame writers instability cleared up overnight without us doing anything. Today fw1 was more unstable than fw0 (one fw0 restart, three fw1 restarts). Still a far cry from fw0 restarting every few minutes yesterday afternoon.

DAQ EDCU connection to digital video channels

After the power outage the DAQ EDCU would not connect to any digital video channels. Today I remembered that the EDCU only uses EPICS gateways to access IOCs on other subnets. The gateway between the H1AUX lan and the H1FE lan was not in the start script. I started the gateway and corrected the script. The only channels not connecting to the EDCU are now the end station HWS channels.

HWS code at end stations

Nutsinee, Jim, Dave:

When we tried to start the HWS EY code ('python run_HWS.py') on h1hwsey, the EPICS IOC started with both ETMY and ETMX channels (though only the ETMY channels had valid data). This appears only a problem with the new python based system at EY, EX only runs ETMX channels. We'll continue this tomorrow.

SUS PI work

Terra, Rich, Jeff, Carl, Betsy, Tega, Ross, Dave

model changes were made to h1susitmx, h1susitmy, h1susbs, h1susitmpi, h1omcpi. DAC allocations were changed, SHMEM IPC added for binary data exchange, new quad master, new C code. There were several rounds of model and DAQ changes.

ETMY HWWD

Dave, Jim

We are unsure if the hardware watchdog unit at ETMY is working after restoration of power. One sure way is to power cycle the unit and monitor the LEDs for the startup sequence, but that would power down the ISI coil drivers. We can check if the code is running by disconnecting one of the monitor cables and checking for the LED error. We'll test some more on the test stand before risking ETMY.

DTS

Jim

The DTS was powered up and made fully functional. Interestingly like H1 some front ends wound up with the incorrect time because the boot server had not synced up. We'll remember to check on that in future (Tega got compile errors on x1lsc0 because of this).

H1 SUS
betsy.weaver@LIGO.ORG - posted 18:33, Tuesday 07 June 2016 (27640)
ETM Charge measurements from this and last week

Attached are the usual long trends of the charge on ETMx and ETMy with the latest data appended.  The ETMx charge accumulation is still decaying towards 0, but not there yet.  The ETMy charge is also near zero in almost all 4 quadrants.  Kissel and I decided we will leave the signs of the ESD bias as they are for another week.  It doesn't look like the ETMx data from today was affected too much with the ISI tripped this morning (the SUS was still damped).

Images attached to this report
H1 SUS (CAL, CDS, ISC, SUS)
jeffrey.kissel@LIGO.ORG - posted 18:29, Tuesday 07 June 2016 - last comment - 20:47, Wednesday 08 June 2016(27641)
H1 SUS ITM LV ESD Driver Installed and Functional
J. Kissel, R. Abbott, T. Hardwick, C. Blair, D. Barker, and J. Betzwieser

After a good bit of chasing our tails and simulink model juggling, we've confirmed that the new infrastructure necessary for the new ITM ESD drivers (see E1600064) is ready to go. 

I'll post more details and screens later, but below are a summary of the things we'd touched during the day's installation:
- Several top-level models are affected by this change, 
/opt/rtcds/userapps/release/sus/h1/models
h1susauxb123.mdl   <-- for the new voltage monitor channels
h1susbs.mdl        <-- in charge of distributing the BIO signals
h1susitmx.mdl      <-- integration into the control system
h1susitmy.mdl      <-- integration into the control system

- We also, sadly needed to create a new QUAD library part, because the ITM ESD driver infrastructure is that much different from the ETM ESD driver system; that now lives here: 
/opt/rtcds/userapps/release/sus/common/models/QUAD_ITM_MASTER.mdl

and in addition, we added a new function to the 
/opt/rtcds/userapps/release/sus/common/src/
CD_STATE_MACHINE.c

called "ESD_ITM" which is called in the BIO block of the new QUAD library part. 
- Also, in the clean up of models, we also re-installed all DAC cards directly from the CDS_PARTS library, which means that a few of the MEDM macro descriptions needed updating -- plus the new macros for the ITM ESD drivers themselves. Those are in 
/opt/rtcds/userapps/release/sus/common/medm
susitmx_overview_macro.txt
susitmy_overview_macro.txt

- Both the new BIO block and QUAD Library parts needed associated entirely new MEDM screens which are now separate offshoots of the ETMs, 
/opt/rtcds/userapps/release/sus/common/medm/quad/
SUS_CUST_QUAD_ITM_OVERVIEW.adl
SUS_CUST_QUAD_ITM_BIO.adl

- I updated the sitemap to call these new SUS_CUST_QUAD_ITM_OVERVIEW screens, passing the appropriate macro files for each optic. The sitemap has been committed here: 
/opt/rtcds/userapps/release/cds/h1/medm/
SITEMAP.adl
Images attached to this report
Comments related to this report
jeffrey.kissel@LIGO.ORG - 20:47, Wednesday 08 June 2016 (27657)
More details about this install can be found in G1601304.
LHO VE (VE)
gerardo.moreno@LIGO.ORG - posted 17:04, Tuesday 07 June 2016 (27639)
IP9 Controller Replacement Attempt at Mid-Y

During the power outage the controller at Mid-Y failed its transition from facility power to generator power, Kyle borrowed the controller from Y-End to power the ion pump at Y-Mid (IP9).  Today I attempted to swap the DUAL type controller (borrowed controller) with a Gamma type, but the Gamma controller failed, brand new controller, so by mistake I installed the original controller that had been removed by Kyle, such controller decided to work now without problems, so I left installed.  I returned the borrowed controller back to Y-End station to power IP11, but it turns out that the signal wire connector is falling apart and needs to be fixed, which will be done on the next opportunity.

The new Gamma controller was bench tested and fuses checked, it continues to fail, it only outputs -50 VDC, not good, it will get send out for warranty repair.

LHO VE (VE)
gerardo.moreno@LIGO.ORG - posted 17:01, Tuesday 07 June 2016 (27638)
BSC5 Annulus Ion Pump Signal Cable

Pulled cable from the annulus ion pump controller on BSC5 all to way to the rack on the south wall of X-End VEA.  Next opportunity we'll have the cable landed and terminated.
 

H1 SEI
krishna.venkateswara@LIGO.ORG - posted 16:22, Tuesday 07 June 2016 (27637)
BRS-Y overnight test under progress

Michael, Krishna

We are investigating the electrostatic/capacitive actuator on BRS-Y by driving it with a small 50 mV modulation at 20 mHz and at different Bias voltages. BRS sensor correction is turned off and should not be turned ON during the test (winds are low). Avoid going near the instrument, if possible.

H1 ISC (ISC)
carl.blair@LIGO.ORG - posted 10:42, Tuesday 07 June 2016 - last comment - 10:19, Wednesday 08 June 2016(27609)
ETMX PI transfer functions
[Rich,[Rich, Evan, Terra, Carl]
[Rich, Evan, Terra, Carl]
We measured the transfer function from the ETMX PI DAC LL channel to the LVLN outputs of D1500129.
The injection was made at the damping filter H1:SUS-ETMX_PI_OMC_DAMP_MODE4_DAMP_EXC.  With H1:SUS-ETMX_PI_OMC_DAMP_OUT_MTRX_1_4 = 1.  H1:SUS-ETMX_PI_ESD_DRIVER_PI_DAMP_SWITCH = ON.  H1:SUS-ETMX_BIO_L3_UL_STATEREQ = 1. H1:SUS-ETMX_BIO_L3_PI_ULLL_SW = ON. H1:SUS-ETMX_BIO_L3_LL_VOLTAGE_SW = OFF 
 
We used imaging to drive from 500Hz to 95kHz.  For example driving at 1kHz we read out a 1kHz, 64.5kHz and 66.5kHz signals.  In the first figure the transfer function is compared to a simulated transfer function derived from components:
>Gain of 80,000/2^17 as we used 80k counts
>sin(pi*f/fs)/(pi*f/fs) for the response of the DAC
>PI Bandpass filter transfer function from LIGO-S1500135-v1
>LVLN ESD amplifier transfer function from LIGO-D1500129-v1 (rough estimate from TF plot -> main error term)
The simulation is in agreement with the measurement other than at low frequency,  Not sure what happened there.  We will make more measurements with an uncertainty estimate from the measured SNR.
 
Friday we found a 20mv peak 1.26MHz noise (a clean sinusoid) on the ETMX LL channel, was not present on other channels.  Going back to investigate with Rich made this noise go away.
When the "ESD drive from DAC" input (J1B) is connected without the lowpass filter selected (PZ3 and PZ4) in the binary I/O there is ~2mV peak noise around 16kHz see second figure.
When the DAC input is connected without the lowpass filter selected in the binary I/O there is ~2mV peak noise around 16kHz. [Rich, Evan, Terra, Carl]
We measured the transfer function from the ETMX PI DAC channels to the LVLN outputs of D1500129
 
We used imaging to drive from 500Hz to 95kHz.  In the figure transfer function is compared to a simulated transfer function that has components:
Gain of 80,000/2^17 as we used 80k counts
sin(pi*f/fs)/(pi*f/fs) for the response of the DAC
PI Bandpass filter transfer function from LIGO-S1500135-v1
LVLN ESD amplifier transfer function from LIGO-D1500129-v1 (rough estimate from TF plot -> main error term)
 
The simulation is in reasonable agreement with the measurement.
 
We found at one point a 20uv peak 1.6MHz noise (a clean sinusoid) on the ETMX LL channel.  Going back to investigate with Rich made this noise go away.
When the DAC input is connected without the lowpass filter selected in the binary I/O there is ~2uV peak noise around 16kHz.Evan, Terra, Carl]
We measured the transfer function from the ETMX PI DAC channels to the LVLN outputs of D1500129
 
We used imaging to drive from 500Hz to 95kHz.  In the figure transfer function is compared to a simulated transfer function that has components:
Gain of 80,000/2^17 as we used 80k counts
sin(pi*f/fs)/(pi*f/fs) for the response of the DAC
PI Bandpass filter transfer function from LIGO-S1500135-v1
LVLN ESD amplifier transfer function from LIGO-D1500129-v1 (rough estimate from TF plot -> main error term)
 
The simulation is in reasonable agreement with the measurement.
 
We found at one point a 20uv peak 1.6MHz noise (a clean sinusoid) on the ETMX LL channel.  Going back to investigate with Rich made this noise go away.
When the DAC input is connected without the lowpass filter selected in the binary I/O there is ~2uV peak noise around 16kHz.
Images attached to this report
Comments related to this report
terra.hardwick@LIGO.ORG - 15:46, Tuesday 07 June 2016 (27630)

We saw the noise at XEnd ESD LL again at ~1.28 MHz, 15mV pk2pk. Rich A. came out to have a look; believe the noise be real (a real oscillation in the hardware). 

On LR drive, we also saw the spectrum glitching (bouncing up and down) when driving at 15.5kHz; goes away with no drive signal (note we did not try other drive frequencies yet). Some beat making a low frequency component?

carl.blair@LIGO.ORG - 10:19, Wednesday 08 June 2016 (27649)

The source of the 1.2Mhz oscillation was identified by opening the spare chasis and looking for marginally stable opamp stages.  
The stage that is marginally stable is U6 page 7 of D1500016.  It can be made to oscillate at ~600khz or ~1.2Mhz.  The stage is a configurable with the pole/zero bypass bit.  

When for example the H1:SUS-ETMX_BIO_L3_UL_STATEREQ control word is set to 2 the stage has a pole at 2.2Hz.  This is the normal low noise configuration.  In this configuration there is no 1.2MHz oscillation.
When this control word is set to 1 the stage is nominally a unitly gain stage.  In this configuration some channels (like UL UR LL and LR) have a Q of >5 at 1.2MHz and can be induced to freely oscillate.  This oscillation may be damped with a 30pF capacitor across R21.

As this oscillation is not a problem in the low noise configuration no changes will be made.  Testing PI channels should be performed with the H1:SUS-ETMX_BIO_L3_UL_STATEREQ control word set to 2.

H1 INJ (INJ)
keith.riles@LIGO.ORG - posted 14:24, Friday 03 June 2016 - last comment - 20:04, Tuesday 07 June 2016(27548)
Implemented new inverse actuation for CW injections with time delay correction
I have copied Evan's new actuation function to the h1hwinj1 directory currently used
for CW injections: ~hinj/Details/pulsar/O2test/. I used the one that corrects for the
actuation delay:  H1PCALXactuationfunction_withDelay.txt.

For reference, the uncorrected version (no "_withDelay") sits in the same directory,
along with the one we first tried last week: H1PCALXactuationfunction.txt.25may2016.
The perl script that generates the command files in.N (N=0-14) has been updated to
use "_withDelay" and the command files regenerated.

The CW injections have been killed and automatically restarted by monit. Attached 
are second trends before and after the gap showing that things look about the same,
as expected, but there is a small increase in injection amplitude (~5%).
Images attached to this report
Comments related to this report
keith.riles@LIGO.ORG - 20:04, Tuesday 07 June 2016 (27642)INJ
Evan wondered if the ~5% increase in total injection amplitude was dominated
by the highest frequency injection or one at lower frequencies. I took a look 
for this time interval and found that the total amplitude is dominated by
the injection at ~1220.5 Hz. Simply comparing spectral line strengths 
before and after the changeover turned out not to be a robust way to
estimate the frequency-dependent ratio of the new to the old inverse actuation 
function, because some pulsar injections (especially the highest frequency one)
are going through rapid antenna pattern modulations during this period.

But comparing the new to the old spectral line strengths at the same
sidereal time several days later (after power outage recovery) gives
robust measures for a sampling of low-, medium- and high-frequency
injections:

Freq (Hz)"Old" amplitude (before switchover)New amplitude (4 sidereal days later)Ratio (new/old)
190.900.322920.322111.00
849.0060.50262.3441.03
1220.5299.37318.701.06
1393.1207.50224.371.08
1991.228.56532.7881.15
These results seem in reasonable agreement with Evan's expectation of a new/old ratio rising with frequency, reaching 15% at 2 kHz. Plots and text files of 4-minute spectral averages are attached for June 3 before the switchover and for June 7 with the newer inverse acuation function.
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