Stefan, Matt, Kiwamu, Evan, Alexa

• ALS DIFF and COMM are working great tonight with the ETMX L2P changes with the oplev running (see Stefan's alog)
• We lock DRMI+arms off resonance much faster if we bring the input power down to 4W, at which point we can easily transition back to 10W without breaking the lock. This is all implemented in guardian now.
• Kiwamu changed the gain of POP18 whitening gain by a factor of 4 because the ADC was saturating
• We added the SRCL mode hopping offset for DRMI+arms off resonance until the asc wfs kick in (the asc wfs turn on faster than before thanks to Dan's modifications, but still should be faster). We also made an edit to the asc wfs loops (see Matt's alog).
• We adjusted the REFLBIAS digital filters to reduce the amount of confusion -- we were compensating and un-compenstating for the same zero/poles with FM3, FM4. Now we just use FM6 (p1.6z40) to compensate for the Boost engaged in the COMM PLL Board to CM Board Path
• Since sqrt(TRX+TRY) goes as 1/f^2 we added a f shaped filter (FM9: z35:p1k) to match the 1/f shape of the ALS COMM loop shape
• The "right side of the river" for bringing the arm off resoance: set frequency offset should be -1000 Hz on the ALS COMM VCO. This has been updated in the guardian
• The ALS COMM FIND IR takes too long; especially the fine tune portion.
• We have transitioned to sqrt(TRX+TRY): With an ALS COMM offset of -150 Hz (green), we engaged REFLBIAS in the first input of CM board. I have attached a StripTool screen shot showing these loops locked; one can clearly see the noise reduction in the IR transmitted signal once we handoff. Some configuration stuff:
  • LSC-TR_CARM_OFFSET = -0.8
  • LSC-TR_CARM FM1 (to pm) and FM9 (z35:p1k) are ON
  • LSC_REFLBIAS FM6 (p0:z1),, FM9 (p1.6:z40) are ON
  • LSC_REFLBIAS gain 0.8
  • LSC-REFL_DC_BIAS gain 1
  • CM Inp1 0dB, CM Inp2 -4dB
  • We engage REFLBIAS gain first, then turn on FM6. Then we reduce CM INp2 down to -32 dB slowly and then turn off the input.
  • We use an ezca servo to adjust the ALS COMM PLL VCO offset so that we don't battle with the REFLBIAS input into the CM board.
  • This is all implemented in guardian CARM_ON_TR except for the CM inp2 ramp down.
  • We took a transfer function of sqrt(TRX+TRY) / CARM; this produced the expected 1/f^2 shape with a detuning peak at around the cavity pole of 40 Hz (see ALS_TR_HANDOFF.pdf -- The blue trace is without DRMI, ie PRM and SRM are misaligned with IR off resonance in the arm, while the red trace is with DRMI_arms off resoance in the configuration described above).
  • We also compared the REFLBIAS signal to the REFL_SERVO_SLOW_OUTPUT (which is essentially REFLBIAS + (-4dB)*ALS_COMM_PLL_CTRL). This looked as we expected. Stefan will add a comment.
  • We were able to increase the LSC-TR_CARM_OFFSET to -1.
• We only had to align the IFO once this morning!
• GPS 1100940241 at the end of the lock.
• Dear Dave, the load matrix is failing to load a lot.

LVEA: Laser Hazard
Observation Bit: Commissioning  

06:45 Karen – Cleaning in the LVEA
08:00 Tweaked the ISS Reference Signal voltage to raise Diffracted Power up to 8.5%  
08:47 Manny – In LVEA to check power racks near HAM2
09:00 Bubba & Mitch – Remove top from HAM ISI Storage Container and position Cleanroom
09:11 Filiberto & Aaron – At End-Y working on PEM power
09:13 Lockheed Martin locating services on site checking route to VPW
09:30 Cleaning crew – First cleaning on storage move cleanroom  
09:45 Bubba & Mitch – Finished in LVEA 
10:00 Bubba – Big-Red moving BSC Storage Container from LVEA Hi-Bay to Staging building
10:20 Added 300ml of water to Diode chiller
10:52 Bubba – Finished moving BSC Storage Container to Staging building
11:37 Filiberto & Aaron – Back from End-Y
11:50 Grant on site to deliver equipment for trenching work
12:35 Hanford testing emergency alarm system   

Alexa, Matt

In an attempt to get stable, if low-bandwidth, loops, we made some cut-off filters.

The new ASC filter in FM5 is:

LP0.2 zpk([0.0025+i*0.499994;0.0025-i*0.499994],[0.1+i*0.0979794;0.1-i*0.0979794;0.05+i*0.193649;0.05-i*0.193649],1,"n")

A couple of old filters that got lost were:

ASC_PRC1_Y FM5 "res1.35" resgain(1.35,10,10)resgain(3.16,10,10)
ASC_MICH_P FM5 "LP15_new" ellip("LowPass", 4, 1, 20, 15)cheby1("LowPass", 2, 1, 100)gain(2, "dB")
 

Aaron and I continued with PEM cabling at EY this morning. We have completed all long cables runs and started installing the permanent power supplies in the DC rack. We disconnected the power supplies powering the microphones in both the VEA and EBAY and placed them in the DC rack. Got a call from commissioners asking us to leave EY, before we could reconnect microphone power with permanent power supplies. Will go back tomorrow morning and power them up. 

PSL Status: 
SysStat: All Green, except VB program offline 
Output power: 33.2w  
Frontend Watch: Green
HPO Watch: Red

PMC:
Locked: 4 days, 16 hours, 33 minutes
Reflected power:    2.6w
Power Transmitted: 22.9w 
Total Power:       25.5w 

FSS:
Locked: 0 days, 0 hours, 43 minutes
Trans PD: 1.810v

ISS:
Diffracted power: 9.39%
Last saturation event: 0 days, 14 hours, 28 minutes  

Work on PEM power at End-Y
Locate Services on site Monday
Trenching work from OBS to VPW on Tuesday & Wednesday
Staging HAM ISI Storage container and Cleanroom in LVEA for 3IFO suspensions storage moves
HAM3 & BSC2 HEPI configuration work on Tuesday

When the modecleaner is kicked out of lock, the FSS oscillates and prevents relocking.

I've reduced the FSS common gain from 30 dB to 24 dB. Now the modecleaner relocks without issue.

I noticed that ALS-Y_REFL_B_DC does not seemed to be aligned. The error threshold has been lowered so that the flag does not go off and we can still lock. I am not sure when this misalignment happened or if this was intentional (I can't remember). Whoever goes down to EY first, can he/she align it?

(Elli, Daniel)

Went to EY to center the green beams on the WFSs. They were too far out for the PZT mirrors. Auto-centering enaged and working again.

Since the ETMX L1 L2P filters gave us a unstable x-arm lock once ALS-DIFF was engaged, we switched to a DC-only strategy:
 - Instead of the the L2P/L2Y filters we simply used flat gains, and tuned them at 0.1 Hz:
     Pitch: -60dB (FM10) * gain of  5.3
     Yaw:   -60dB (FM10) * gain of -0.7

 - We also tweaked the ESD L2P/L2Y's at 2Hz:
     Pitch: gain of 0.021
     Yaw:   gain of 0.007

 - This left some AC pitch fluctuations on ETMX. The OPLEV took care of that. We now have a stable ALS DIFF and COMM running in this configuration.

model restarts logged for Sun 23/Nov/2014
2014_11_23 02:27 h1fw1

one unexpected restart. Conlog frequently changing channels log attached.

On the way to better initial alignment automation, there are some new scripts for TMS alignment in:

/opt/rtcds/userapps/release/asc/h1/scripts

they are alignTmsxDither.py and alignTmsyDither.py which use baffleAlign.py.  These are still a work in progress.  After testing is done, we will need to incorporate them into the IAS guardians.

The usual scripts (e.g., alignDitherFull.py) should be as before, and backup copies are in old_2014-11-24 just in case.

Matt, Dan

After Alexa gave us a quick alignment tutorial, we started by fiddling with the dither alignment of the X-arm.  The PD thresholds for dithering across the baffle PDs were set to very small values, so small that the dither would declare victory before it even started.  Matt has been working on the initial alignment, I'll let him say more about it.

We noticed that the green spot on the TMS-Y mirror, visible through ETMY, is very low.  There are large offsets in the EY green QPDs that steer the beam to what looks like a bad place on the mirror.  Zeroing these offsets (which is where they were for most of the last six months) would have forced us to begin a painful realignment procedure, so we left them as we found them.  Historically it looks like people have set these values to maximize the buildup in the arms, but it's hard to believe that the optimal beam position is so far off-center.

With the arms well-aligned for green we aligned the corner optics - IM4, PR2, PRM, BS, SRM.  The scripts for this went quickly, about five minutes.

Then we locked the DRMI, with the arms misaligned.  Locking tonight was fast and robust; the DRMI would lock within a few minutes (rarely more than 5 minutes), and would remain locked for tens of minutes.  There were many unexplained lock losses, so things are not as stable as we'd like, but we didn't see any mode hopping and the sideband buildup was consistently good.  Over three hours of DRMI locking we didn't observe a significant drift in the alignment.

We went through the DRMI guardian and commented out lots of gain/switch settings that weren't needed, mostly for the DC centering.  The script is now pretty fast, it goes from lock acquisition to ASC loops on in less than 30 seconds.  We did not observe any unexpected long pauses.  The duration of the script is dominated by ramping the SRM and PRM M2 gains, this takes 9 seconds total (4.5sec each).

We re-enabled the PRM and SRM2 offloading to M2.  We found the SRM offloading was a little flaky and sometimes broke the lock.  To make this a little gentler, we reduced the initial gain ramp to 1, and ramped the rest of the way (to 4.5) after the WFS turned on.

We measured the LSC OLTFs and found that MICH and PRCL didn't have much phase margin (~25deg each).  We reduced the gain for these loops so that they both have >30deg.  The MICH gain is now 3 (was 5) and PRCL is 15 (was 22).

Afterwards I mucked around with the OMC, I found a set of good misaligned values for ITMX and ITMY that minimized the RIN at the dark port when the other ITM was aligned (presumably this steers ghost beams away from the OMC).  Following Gabriele's instructions I used the picos to center the beam on IMC WFS A and added some offsets to the IMC ASC loops; this reduced the intensity noise measured by the ISS second loops PDs by a factor of three or so.  I tried to engage the ISS second loop but failed.  The script posted here did not appear to work; I tried to follow these directions but the loop was unstable.

Plots attached are MICH, PRCL, SRCL loops before we reduced the gain to get some phase back in MICH and PRCL.

(Alexa, Evan, Stefan, Matt)

The ETMX bounce mode has been limiting us in locking ALS DIFF, and causes us to lose lock when the ESD saturates. The first attachment shows the coil outputs of the stages, and there is a clear peak in the ESDs (note this screen shot was taken with a much lower gain in DIFF and with the boosts off; this peak causes saturation when the DIFF gain is nominal). The second attachment shows the bounce mode appearing in the oplev spectrum. You can see that this mode starts to appear Friday and gets worse into today. Thursday night the mode looks fine, which explains why we were able to lock DIFF Thursday night. At some point Friday afternoon we turned off the ETMX L2 oplev damping; however, we see this mode ringing up before this was switched off.