model restarts logged for Fri 30/Jan/2015
2015_01_30 04:45 h1fw0
2015_01_30 08:03 h1fw0
2015_01_30 11:02 h1fw0
2015_01_30 17:27 h1fw1

C1PLC1 7:54 1/30 2015

C1PLC2 7:54 1/30 2015

C1PLC3 7:54 1/30 2015

unexpected daq restarts. Beckhoff corner station restart for fast shutter install. Conlog frequently changing channels report attached.

Alexa, Elli, Sheila, Kiwamu, Rana, Evan

Summary

With CARM controlled by a combination of sqrt(TRX+TRY) and TR_REFL9 (i.e., REFL9I normalized by TRY), we've achieved a power buildup in each arm that is 800× the single-arm buildup. We believe this corresponds to a CARM detuning of 5 pm.

At this point, REFL_A_LF is at about 2.3 mW, compared to 40 mW when the arms are anti-resonant. If this is truly an indication of the power reflected back from the PRM, this means that the visibility of the interferometer is in excess of 90 %.  We do not have TCS on today.

One major roadblock to further progress seems to be angular instability that is seen at the AS port. We have ASC feedback from AS_B_45_Q to ETMX and ETMY, but the bandwidth is too low to suppress the 1 Hz motions that we see. We may need to spend some time increasing the WFS bandwidth, or resort to more aggressive oplev damping.

Details

A laundry list of things we've done today to troubleshoot the transition:

• Locking at 4 W input power. This appears to reduce the amount of angular instability during CARM offset reduction.
• Engaged oplev damping on ITMs.
• Increased the DHARD WFS BW. The gains are now 0.1, FM2 (+20dB) is no longer on compared to Elli's old alog (LHO#16345)
• Changed the DARM loop shape (LHO#16387) to achieve higher bandwidth.
• Switched from REFL_A to REFLAIR_A to avoid saturation while locking (LHO#16381).
• Because TCS was accidentally turned off (LHO#16385), we decided to retune the demod phases of the 3f signals. With CARM controlled by sqrt(TRX+TRY), we've adjusted the phases as follows:
  • 27 MHz: 91.3°→111.8°
  • 135 MHz: 65°→25°
• We took a TF from TR_REFL9 to sqrt(TR) at -25 ct of offset on sqrt(TR). Above 10 Hz, the TF was about 50 dB with -180° of phase. Below 10 Hz, the TF began to rise. Therefore, we installed a 1.6 Hz pole, 40 Hz zero in the TR_REFL9, and +50 dB. This behavior does not seem to correspond with simulated TFs given, e.g., in T1400298.

Based on the measured losses in the arms (an average of 110 ppm), we expect an interferometer recycling gain of 32 W/W and a coupled cavity pole of 0.6 Hz (i.e., 9 pm) [using eqs. 6 and 8 from Fritschel et al. 2001]. Therefore, we believe that the arm buildup should be about 1000× the single-arm power with CARM at 0 pm. This is consistent with earlier estimates made by others (LHO#15390, T1000294).

A list of transition steps not yet implemented in the guardian:

• Increase the gain of IN1 on the IMC board by 6 dB.
• Starting at a sqrt(TR) offset of −20 ct, ramp the offset to −30 ct while reducing the DARM gain in the input matrix from 40 ct/ct to 20 ct/ct.
• Turn off the WFS (they appear to flip sign around here).
• Ramp the offset to −36 ct, and ramp the DARM input matrix coefficient to 8 ct/ct. Turn on the WFS with the opposite sign, and 10 dB less gain.
• Turn on TR_REFL9I→CARM feedback with an input matrix gain of 3 ct/ct, and no TR_REFL9I offset.
• Adjust the CARM offset to -41 cts, and hold the TR_X/Y_NORM outputs

Our last three attempts are 11:24:48 UTC, 11:00:27 and 10:37:35 Jan 31.

New models have been prepared for the splitting the end station isc model:

• New model directories were created in als/h1/models and als/common/models
• als/h1/models contains h1alsex.mdl (DCU 85) and h1alsey.mdl  (DCU 95), as well as the updated IPC file H1.ipc_alsnew.
• isc/h1/models contains h1iscex_new.mdl (DCU 126) and h1iscey_new.mdl (DCU 127).
• als/common/models contains ALS_END.mdl
• isc/common/models contains ASC_END amd LSC_END (no change).
• The integrator has been moved to cds/commmon/models/integrator.mdl and cds/common/src/integrator.c.
• Ramping functions are located in cds/common/models/ramp.mdl and cds/common/src/ramp.c.

The old h1iscex and h1iscey are still the default. To activate the new split models, h1iscex_new  and h1iscey_new need to be renamed, the IPC file copied over chans/H1.ipc, and then everything recompiled. All in svn.

J. Kissel, R. Adhikari, S. Dwyer,

By happenstance calling for another reason (see LHO aLOG 16390), Rana and Sheila informed me of woes at ETMX: a sudden trip, some further trip, followed by more trips of the watchdog. Unsure of what was going on, they had mashed a bunch of buttons in attempt to fix the problem. 

After some remote MEDM'ing, I could tell that the BRS-rotation-corrected, GND X STS signal had gone bonkers, which was being used as the X -direction Sensor Correction signal since Krishna had resurrected the BRS earlier this afternoon (see LHO aLOG 16380). 

I've since switched the STS2CART input matrix to use the normal X-direction STS signal for sensor correction (changed the STS2CART matrix to use STS B for X input to sensor correction instead of STS C). I'm not sure what's gone wrong with the BRS (too difficult to diagnose remotely), we'll figure that out later.

Further, Sheila and I used the SDF system to restore all of the button mashing they'd done. Now only the expected differences from "nominal" remain -- my switch of the STS2CART input matrix, and Krishna's turning on the outputs of the Rotation and Torque correction paths for the STS. Again, the latter no longer has any impact because this GND super sensor output is no longer being used. I second Hugh's love of the new SDF system!

J. Kissel

Since Hugh had left the servo OFF for later characterization (see LHO aLOG 16388), I wanted to be sure the pressure wasn't drifting, which might potentially cause subtle weirdness for the commissioning vangaurd. I've logged in remotely to check on the HEPI Pump Servo's Differential pressure signal, and found that it was starting to turn downward, and was "accelerating." As such, I've turned the corner station's HEPI pump servo back ON, around 9:30p Local, on the phone with the control room while I did so. The pressure bounced back to 70 [PSI] almost immediately. 

We'll catch more HEPI pump servo off, DRMI data another night.

Kiwamu, Sheila, Rich, Daniel, Rana

Summary

We are close to saturating REFL_A_RF9 during our hand-off attempts from sqrt(TRX+TRY) to REFL9I.

For the time being, we are switching to REFLAIR_A_RF9 for the handoff. Sheila and Rana have done some rewiring on the ISC rack so that the I&Q demodulated outputs of REFL_A_RF9 are replaced by REFLAIR_A_RF9.

Details

The attachment shows the 9 MHz rms monitors for REFL_A and REFLAIR_A during a lock acquisition attempt. After some discussion, Rich and Daniel have concluded that the RF monitor channels are calibrated into dBm, as measured at the output of each PD with a 50 Ω load. REFLAIR_A is sitting comfortably below −10 dBm. REFL_A, however, peaks as high as +15 dBm. The amplifier in the RFPD is an LMH6624, for which the minimum output swing is reported as ±4.4 V into 100 Ω. Since the amplifier has a 50 Ω series resistor on its output, that's 20 dBm of power delivered into a 50 Ω load. If we want to keep distortion to a minimum, we should stay well below this limit.

The Pressure runs pretty darn solidly at 70 psi with the servo off.  I don'think it would trend off more than a few tenths of a PSI overnight.  I'll come out over the weekend and adjust if needed.

Some coherence with OAF-CAL_MICH goes away with the servo OFF, very little coherence seen in PRCL or SRCL

DRMI was locked for 9 hours until ~1527utc 30 Jan.  POPAIR_B_RF18_I_MON was at 300 when lock was lost.

Measurement started at 0700utc for HEPI Pump Servo On data; Measurement here at 220015 during a DRMI stretch for Pump Servo Off data.  Lots of activity during this time so a quieter stretch with servo off would be good to have.

On the attachment you see plenty of coherence between 10 & 100mHz that pretty much goes away when the servo is turned off.

Also attached is the amplitudes of the Mich and the Pump Pressure and the STS floor seismometer.  Input motion looks pretty similar but there have been activities in the LVEA today.  The weird nature of the Mich signal at higher frequencies may indicate I'm too close to the lock loss or something.  Will repeat this when the DRMI is quiet.

(Elli, Richard, Dave, Rich, etc.)

Last Tuesday around 1pm the readback channels of the TCSX CO2 laser system went crazy. We tracked this to the AI/AA chassis which were not powered. Not clear why, but maybe the power connector fell off, when someone worked in the PEM rack? When the digital system goes down, the chiller doesn't get a temperature setpoint. It will then turn itself off with a fault. In turn the laser shuts off. With the power restored, it was possible to turn the chiller on, and then the laser. Both actions need to be done on the floor. The laser is now back in operation with the requested heating set to 0W. Once we leave we can set it back to 0.3 W. The mask is set to central heating, but the monitor for the annular mask is flaky.

In conclusion: The TCSX CO2  was probably off since last Tuesday 1pm.

Rana, Alexa, Evan

We wanted to increase the phase margin in the RF DARM loop, so that we have room to increase the UGF.  In the LSC DARM filter module, we have added filter FM9 (zpk([200;200],[400+i*692.82;400-i*692.82],1,"n")), which cancels the two poles at 200 Hz present in our FM8 LLO filter. It also adds a roll off at 800 Hz. See DARMFilter_changes.pdf to compare the TF with FM8 only vs FM8 + FM9. The UGF of the RF DARM loop is 30 Hz with a phase margin ~32 deg (compared to the old ~20 deg margin). I have attached a plot with the modeled and measured RF DARM OLTFs, and one that compares this with the old loop where FM9 is turned off.

Configuration for RF DARM: FM2(z2:p0), FM3 (resG), FM4(z4^2:p1^2), FM8(LL0), FM9(Lead200)

Note, the configuration for ALS DIFF: FM2(z2:p0), FM3 (resG), FM7(SB60), FM8(LL0), FM10(RL33)

I added 250 ml of water to the chiller.

06:30 Cris and Karen into the LVEA

08:00 DRMI locked when i came on shift

08:01 Jim taking measurements wjile DRMI locked

08:02 Lock broke. Sigg flashed the mode cleaner

08:02 I was able to relock DRMI by re-requesting the 'DRMI_1F_LOCKED_ASC

08:38 Jeff B into Optics lab

08:39 Janeen and Gary moving stuff from VPW into LVEA.

08:47 Manny will be going to collect 3IFO stuff at Ends and in Corner.

10:00 Commissioning starts

There is a problem with the signal from the ITMY OSEM, it was verry noisy durring the lock losses last night and it is still noisy now, this seems to be always this way. 

The attached screen shots show the signals up the chain on each quad.