(Peter K, Richard M, , Filiberto C, Daniel S)

We noticed that the fast channels corresponding to H1:IMC-PWR_IN and H1:IMC-PWR_EOM were never hooked up. This required installing the PD interface box in the PSL enclosure, running the DAQ cable into the PSL and installing a tee in the photodetector readback. (These channels have previously been hooked up to the EtherCAT system, so they that they are available to the rotation stage.) The EOM channel is currently railed and needs an adjustment of the PD gain.

EPICS updates:

• Added buttons for these channels to the IMC overview screen.
• Fixed the screen for the PSL rotation stage in the sitemap.
• Added rotation stage button to the IMC overview screen.

K. Venkateswara

In response to the problems reported in 16391, I centered the beam-balance in BRS within the nominal range of the angular readout. To do so, I physically moved a small mass on the balance using the bellows mounted on the front face of the vacuum can. After a few tries I was able to center it to within a ~1/3 of the full range. The balance was then damped to low amplitudes and I repositioned the damper.

BRS is now functioning correctly. The first attached plot shows the tilt-subtraction at work. The second shows the coherence between various sensors. The low coherence between the tilt-subtracted super-sensor and BRS RY shows the subtraction is working reasonably well.

Had to boot EX which seems to be a biweekly occurrence. The problem aren't the PLCs or the hardware interface but the communications. The tcioc stops updating with a "No DS mailbox available" error message. This is always preceded by numerous "CAS: UDP  recv error". So far, the only way to fix it is to reboot. I did notice that h1ecatx1 runs the Windows firewall whereas the c1 and y1 run a commercial product.

C. Reed, D. Moraru

In an effort to ameliorate the daqd crashes on framewriters 0 and 1, we have enabled jumbo frames on the private network links between the framewriters and the QFS gateways under WP 5035.  This was the last remaining major difference between our configuration and the LLO DAQ (that we know of).  If this doesn't help, we will need to keep looking for a cause for our framewriting woes.

Betsy, Travis

Because of new filters loaded by Rana last week, I wasn't sure there had been an update to the safe.snap file for the ITM and ETMs.  Since the IFO was down for Tuesday chaos, we therefore took new ones and committed them to svn.  While we were at it, we committed the safe.snaps for the 3 MC SUSes due to my addition of the SDF column to the files yesterday.

WP #5031

Dataviewer has been updated to version 2.9.1.1 for Ubuntu workstations in the control room.  This is to fix bugzilla 786, allowing dataviewer to display raw data of multiple signals in a single plot in playback mode.

• We edited the guardian so that it reliably gets us to a CARM offset of approximately 10 pm, (TR_CARM = 30)
• We are now using an OPLev servo at DC on PR3 to help with the alingment drifts we see everytime we get some decent power build up in the IFO. 
• We noticed that the SRCL and MICH gains needed adjsutment.  At a TR CARM offset of 30 we reduce the SRCL gain by about 50%, from -45 to -26, and increase the  MICH gain by a factor of 3 to 6
• We attempted to use the MICH WFS, they worked well without the arms, we used the highbandwidth configuration.  We tried the CARM offset reduction with these two loops on, the alingment indeed stayed better, but we also lost lock suddenly.  Elli saw in at least one of these lock losses that the MICH WFS were oscillating, so we are now leaving them off. It would probably be worthwhile to try the low bandwidth version. 
• We went to ISCT6, replaced the 2 0.5 ND filters with an absorptive ND 1.0 filter and checked the centering on ASAIR A. This turned out to be a different level of attenuation than we had with the 2 ND 0.5s so we changed the gain in ASAIR_A_RF45_I and Q to 5.4

We then made several attempts to transition off of TR_CARM.  As on friday, we are able to get to low CARM offsets, and sit there stably, but haven't been able to turn off TR_CARM yet.  We found that we could sit at about 5 pm (TR CARM = -39) stably with just TR_CARM on. 

Transition attempts:

At -36 in TR_CARM, engage analog REFLAIR 9 with 40 dB total gain on summing junction and CM board. 

At -36. engage REFLAIR9 with and offset of -1.8, tried turning off FM 9 (the complex pole compensation) in TR_CARM.  Lost lock at 7:23:45

We've had trouble engaging the DHARD WFS with the opposite sign at the small CARM offsets tonight, which on Friday seemed like it was key to being stable at low offsets.  

J. Kissel, H. Radkins,

In further pursuit of HEPI Pump Servo Noise -- found to be coherent with the IFO at low-frequencies (see G1500099, and LHO aLOGs 16386, 16342, and 16239) -- Hugh and I briefly terminated the pressure sensor inputs to the HEPI pump servo (see times in LHO aLOG 16419), in attempt to measure the ADC noise of the PC/104, Athena II, 16-bit ADC (see Diamond System's product website for data sheet and user manual). 

Sadly, there appears to be no difference between the channels when the sensors are plugged in and when the sensors are terminated.

What's confusing about this, is that we know the pressure preamp (D1101839, which adds a gain of 151 [V_diff/V_diff] to each supply and return sensor) and the input instrumentation amplifier inside the servo (pg 2 of D0901559, adding a gain of 2 [V_se / V_diff] for a total of 300 [V_se / V_diff]) are functional and calibrated correctly in the EPICs database. If that weren't true, the DC signal on each sensor's EPICs readback would not match the dial gauges on the system.

Further, as mentioned on pg 13 of G1500099, if the pressure sensor's calibration is 0.3 [mV/PSI] (0 to 100 [mV] over a 0 to 300 [PSI] range), typical supply pressure is 70-80 [PSI], then the pre-amplified, instrumentation-amplified, supply pressure signal reaching the Pump Servo ADC should be roughly 6.3-7.2 [V] single-ended, using plenty of the range of the 0-10 [V] ADC range. On the other hand, the return pressure, typically ~5 [PSI], would arrive at the ADC as only 0.45 [V]. Small, but still well above the 10 / 2^16 = 1.5e-4 [V/ct] resolution.

So, the DC signals add up and agree with dial gauges, the signals should fit well within the ADC's range well above it's bit resolution, and responds appropriately to little steps in the control pressure. So why don't we get a change in ASD between terminated and connected?

We'll continue to investigate tomorrow morning. 

I attach three things:
(1) 2015-02-02_H1HPI_PumpServo_ADCNoiseCharacterization.pdf 
The pudding. Amplitude spectral densities of the Supply Pressure (H1:HPI-PUMP_L0_BSC2SUP_PRESS), Return Pressure (H1:HPI-PUMP_L0_BSC2RET_PRESS), and the calculated Differential Pressure (H1:HPI-PUMP_L0_DIFF_PRESSURE) for three different times. RED is with the pump servo closed (the current, nominal running state), BLUE is the with the pump servo open, but the sensors still connected, and MAGENTA is with the pump servo open and the sensor inputs terminated. As you can see -- no change between BLUE and MAGENTA.

(2) 2015-02-02_HPI_PumpServo_Pics_A.pdf 
A collection of pictures of the HEPI Pump system, as built at LHO.

(3) 2015-02-02_HPI_PumpServo_Pics_B.pdf 
More pictures of the HEPI Pump system, including pictures of the terminating plug used and how / where it was connected (starting on pg 9).

Following the pin out shown in D0901559, where (on pg 1, upper left corner) connectors J1A and J1B are shown to bring in the field Supply and Return pressure signals, I crafted two, dummy, DB9, pressure sensor terminators by connecting the + and - legs (pins 4 and 6) of the differential input with a 100 [ohm] resistive load. All other pins (i.e. the +10 [V] supply voltage to the pressure sensor, and the +/- 15 [V] supply voltage to the pressure sensor preamp) were left open. Again, see pgs 9 and 10 of 2015-02-02_HPI_PumpServo_Pics_B.pdf.

On Saturday we closed the ISS second loop and dither-locked the OMC, with a single bounce from ITMX.  In this state we were able to measure the RIN at the OMC DCPDs with the 2nd loop open and closed.

With the ISS second loop closed, the relative intensity noise at the OMC DCPDs at 100Hz is about 5x10^-8 / rt[Hz].  Above 100Hz, the OMC DCPD RIN is limited by intensity noise; below 100Hz the noise is from something else.  See the first plot.  The OMC DCPD sum was ~14mA at the time of the measurement, and the shot noise RIN should be 5x10^-9/rt[Hz], well below the measured noise floor.

Compared to Gabriele's measurement from November, the noise with the ISS 2nd loop open is ~10x worse, compare the second plot, upper right, to his third plot, lower right & left.  Is the excess noise due to jitter into the IMC?  We did not take the time to fiddle with the IMC WFS offsets.  Gabriele measured 10^-8 RIN/rt[Hz] at 100Hz with the 2nd loop closed, but we measure 3x10^-8 /rt[Hz], so above 100Hz we may be limited by the gain of the ISS 2nd loop.  If this is the case, then improving the RIN out of the IMC could reduce the intensity noise at the AS port.

In the second plot, we compare some signals with the ISS loops open and closed.  The second loop suppresses the noise at the OMC DCPDs by about a factor of 100 (lower right plot).  Note that in the lower left plot, of the RIN observed by the IM4 trans PD, the ISS first loop only improves the noise at high frequency.

There is a peak in the intensity noise at 700Hz that is not suppressed by the second loop.  This also seems to be ~10x worse than what Gabriele measured in November.  It's not clear where the peak is coming from, it's seen by the IMC WFS (see third plot), but not by any PEM or IMC length channels that I can find.  This peak is broad enough that it may cause trouble with the OMC ASC dither lines.  (L1's dither frequencies are around 550-650Hz.)

Elli, Dan

On Saturday we made some changes to the DC centering loops in HAM6, for the AS WFS and the OMC.

==== AS WFS loops diagonalized ====

We started by measuring and inverting the sensing matrix for the AS WFS.  The new control matrix has been loaded into the ASC output matrix.  The old control scheme was AS-WFS-A --> DC3 --> OM2, AS-WFS-B --> DC4 --> OM1, all with matrix elements of unity.  The new output matrix elements are:

To compensate for the new matrix elements we changed the gains on the DC3 and DC4 loops to be 0.03.  Based on the plot of the noise suppression it looks like this corresponds to a UGF of ~1-2Hz, but we need to measure the loop shapes during a break in the lock commissioning.

==== Alignment of OMC REFL path ====

With the fast shutter installed we felt confident to realign the beam going to the OMC REFL QPDs.  Previously this path had been roughly aligned, but we hadn't worked out the assignment of the in-vac picomotors and centered the beam on both OMCR QPDs.  The picomotors are on mirrors M9 and M10, see the diagram in D1000342-v14.  Both picomotors are upstream of the OMCR QPD sled.

We centered the beam on OMCR_A and moved each picomotor until OMCR_A_SUM dropped to 50% of the peak value.  Pico #6 moved half the distance of Pico #5, so we inferred that Pico #5 is driving M10 in the diagram, and Pico#6 is driving M9.  So, the HAM6 picomotor assignment is:

After centering the beam on the OMCR QPDs we checked ISCT6 to make sure the OMCR beam was still coming out.  We found it was still well-aligned on the table (centered in periscope mirrors and lenses).

==== OMC SUS -> OMC {POS,ANG}  transfer function and OMC alignment topology ====

To decouple the OMC alignment from the AS WFS centering, we wanted to use the OMC SUS as an actuator.  (Following L1, we had added this functionality to the OMC and OMCS models in December.)  The trick is to make the OMCS look like a simple pendulum so that the OMC ASC loops can drive OM3 (a tip-tilt) and the OMCS at the same time.

We measured the OMCS --> OMC QPD transfer function with white noise, in the style of the SUS group.  The result, for pitch, is the first plot attached.  Then, we constructed some filters to remove the peaky features in the TF and make it look more like a damped tip-tilt.  The poles and zeros were loaded into the OMCS ASC filter banks, along with a 30Hz cheby low pass.  The result is a somewhat bumpy 1/f^2 transfer function above a ~1.7Hz feature that looks like a low-Q resonance; see the before/after comparison in the second plot.  The TF is a little more gnarly that we would like, I think we will make some tweaks after measuring the shape of the full OMC alignment loops.

With the new filters for OMCS ASC pitch and yaw we were able to measure an {OM3, OMCS} --> OMC QPD sensing matrix, invert, and closed the OMC alignment loops.  A screenshot of the output matrix is attached.  Because of the short lever arm from OM3 to the OMC QPDs the control matrix is not very diagonal, this could be a problem.  The loops were stable (at least, on a Saturday evening), and we could close the AS WFS DC centering and the OMC alignment loops independently.  We found that if we set the gain of the OMC alignment loops too high we would saturate the OMC suspension drive.  This could also be a problem for this alignment topology (along with cross-coupling between the OMCS degrees of freedom), depending on how much gain we want with the dither loops.  We need to measure the OLTFs, trend the control signals during weekday seismic noise, etc. before we can be confident that this distribution of the control is robust.

The fourth plot compares the beam jitter on AS WFS A and OMC QPDA, with the loops open and closed.  The noise befow 1Hz is suppressed by a factor of ~several.  The loops add some noise around 3Hz.

Daniel, Jim, Dave:

WP5034. We have changed the PEM, CAL and ISC models for EX and EY and created the new ALS model. For this week's test, CAL will be integrated into PEM and the ISC model split into two (ISC and ALS). The IOP and ODC models will remain unchanged. 

We have compiled the models h1iscex, h1alsex, h1pemex, h1iscey, h1alsey, h1pemey against a modified H1.ipc file. We have not performed "make install" and have reverted back to the running H1.ipc overnight.

Morning meeting:

SEI running TFs as target of opportunity for feedforward on all ISIs

Krishna will be here this week for BRS work at EX

HEPI pumpstation work

TJ working on RM and OM SUS Guardians

Jamie will be here this week working on Guardian

Matt Heintze will be here this week for 3IFO work

Beamtube cleaning ongoing

Bubba working on 3IFO purge plumbing in LVEA

OPS Shift Summary:

6:30 Cris and Karen to LVEA

8:19 Karen to EY, Cris to EX

8:23 Ken working on air handlers at EX and EY

8:50 Corey to squeezer bay

8:51 Ken to EY

8:51 Bubba to LVEA H2 input area

9:05 Corey done

9:19 Jodi to mid stations

9:23 Karen done

9:33 JeffK, Krishna, and Hugh to HEPI pumpstation

9:40 Jodi back

10:06 JeffK, Krishna, and Hugh done

12:00 Ken to EX HVAC work

13:48 Ken done at EX

13:54 Fil to MY for parts hunt

14:24 Fil done
 

I locked both arms with green this morning, and attempted to lock DRMI, but was foiled due to sneaky filter settings and constantly changing methodology (unable to follow OPS instructions due to changes by commissioners).

J. Kissel, H. Radkins

Hugh and I continue to investigate the corner station HEPI pump servo noise at its source. As such, we've switched the servo OFF and terminated the two pressure sensors used for the loop error point (read in as H1:HPI-PUMP_L0_BSC2SUP_PRESS, and H1:HPI-PUMP_L0_BSC2RET_PRESS) with 100 [ohms] at 3:45 pm (23:45 UTC). The hope is to quantify the servo's ADC noise floor. We intend to leave it in this configuration for an hour or so before restoring it. Meanwhile, Hugh continues to manually maintain the pump pressure (though very little has been required but for a few 1 [ct] tweaks).

The first attachment is a time series of the HAM6 Watchdog, the Fastshutter State, and a GS-13 trace on HAM6.  The switch to low Gain is clear on this last trace.  This is a 5 day trend and the ~20 minutes needed to get the below .005Hz BW data is comfortably unmolested by the ISI or the fastshutter--the start times of the Spectra calculations begin at the vertical black lines.  As for ISI trips and shutter fires--there were none.

The High Gain Spectra period begins at 0800utc on 29 Jan, the Low Gain Spectra begins at 0800utc 1 Feb.

The second attached graph has Horizontal GS13s on HAM6 in High and Low Gain on the upper plot.  The Verticals are in the lower plot. High Gain Spectra is Dashed, Low Gain traces are Solid.  Also shown is our ADC noise in counts.

One caveat is that the ground motion is different at the two times.  The third attachment shows the Cartesian DOFs for the HAM6 GS-13s in the upper two plots and the ground noise in the bottom plot.  We've had a ground motion decrease in the microseism frequencies and below during the low gain period.  You can see the Low Gain Spectra are at the ADC level below 50mHz.  And the 10x signal reduction expected is more like 5x below these frequencies.  If this conclusion passes mustard, we'll have to revisit the GS13 triggering delays/levels.

DTT template is /ligo/svncommon/SeiSVN/seismic/Common/MatlabTools/HAM6_GS13_GainNoiseTest.xml

J. Kissel, J. Warner, D. Barker, E. Merilh, TJ Shaffer

The one final quiver in our arrow against the sharp HAM3 0.6 [Hz] resonant feature was a computer (as suggested e.g. here), so we did so this morning. Sadly, it did not cure the problem. For now, we continue on, running in the configuration defined by Seb last week, see LHO aLOG 16100, in which the RY blend filters at a higher blend configuration, which is the only thing we can find that seems to help (see LHO aLOG 16001). This has now officially become a low-priority until it begins to quantifiably impact IFO performance.

A Recap of all of the things we've tried that DIDN'T make the feature go away:
- Restarting the front-end process LHO aLOG 15759

- Full power-down of Front-end and I/O Chassis (This aLOG)

- Coil Driver Swap LHO aLOG 16071, LHO aLOG 16061, LHO aLOG 15981

- Changing Suspension Damping LHO aLOG 16013, LHO aLOG 16001

- Changing Isolation Loops LHO aLOG 16001

- Location of Sensor Correction; ISI vs HPI LHO aLOG 15941. LHO aLOG 15933

- Changing from STS2 B to A; In analog LHO aLOG 15811, In digital LHO aLOG 15927, LHO aLOG 15894

- Checking between ADC and sensor correction bank LHO aLOG 15783

- Turning OFF CPS satellite amplifiers, checking jumper settings (oscillators, jumpers, etc.) LHO aLOG 15751

- Adding a large mechanical offset to relieve supposed mechanical rubbing LHO aLOG 15751

- Waiting LHO aLOG 15565