J. Kissel, A. Pele, S. Ballmer, K. Izumi, S. Dwyer

We're slowly but surely chugging through implementation of a well-understood ALS DIFF control scheme. On Monday, I designed a control system that used the real ALS DIFF noise, the increased UIM driver strength, and 2 QUADs worth of actuation (see first attachment for design plots). Over the past few days, Arnaud, Sheila, Stefan, and Kiwamu have been measuring all the necessary transfer functions to confirm my model of the plant. I've compiled the results and attached the comparison of what we have thus far (see second attachment for comparison of model against measurement). There is excellent* agreement between model and measurement. We have installed the complementary distribution filters, and we're now fitting the measurement results to obtain plant inversion filters (as mine were just low-Q guesses, because I knew optical lever damping, different top-mass local damping, etc. would cause subtly different frequency dependence).

Of note: 
- *There is still a factor-of-4 discrepancy between the model and measurement at the test mass. Kiwamu and I have modeled the ESD in two different conceptual ways, and come up with the same factor of discrepancy. For now, we'll just accept the measurement as canon and move on, but it would be really nice to understand this mismatch.
- Unlike what I've modeled, Stefan has convinced me to go forward with inverting the frequency dependent plant to look like a 1 [Hz], Q=1 single pendulum transfer function, with a DC actuation strength of 1e-12 [m / ct]. 

The DC gains between the stages are as follows:
TOP: 4.769e-10  [m / ct_{TOP}]
UIM: 5.328e-11  [m / ct_{UIM}]
TST: 1.760e-13  [m / ct_{TST}]

For gain ratios of:
TOP / TST:  3.69e-4 [ct_{TOP} / ct_{TST}]
UIM / TST:  3.30e-3 [ct_{UIM} / ct_{TST}]

Taking over afternoon for Thomas

• SR2 Alignment work done for the day (Jason O)
• Dust Alarms at EX (probably due to Ken?)
• Dust Alarms near HAM4 (the 0.3um counts have been a few hundred counts most of the day)
• TCSx Table Hartman work (David H)
• Transitioned LVEA to Laser HAZARD around 2pm (Kiwamu)
• TCS laser work (Alastair & Matt)
• Ops Meeting from 3:00-3:30

Installed the ESD drive at EY.  The interlock to the Pressure Gauge functions properly.  Again had a problem the a Neg HV supply.  Similar to EX the unit powered up and worked for a while then tripped off and never turned back on.  Replaced it and everything seems to be working.  Drove excitations through the ESD out filterbank and saw signals on the oplev.  Left further testing to Kiwamu.  I was not completely satisfied with our results.

- Aidan turning on laser with enclosure locked to remain in laser safe, going to lock the intensity of the laser.
- Fil and McCarthy working on ESD at EY
- Hugh to the west bay test stand area
- Betsy to HAM4
- Dale to HAM4

Corey took over at 12:00 PM PT

• Y (longitudinal): +0.4 mm (west)
  • Tolerance: ±3.0 mm
• X (lateral): -1.2 mm (south)
  • Tolerance: ±5.1 mm
• Z (vertical): +0.4 mm (high)
  • Tolerance: ±3.4 mm

I have started the setup for the SR2 pitch/yaw alignment (it differs from the position alignment) and hope to finish tomorrow morning so we can get a first look at SR2 pitch/yaw before the afternoon transition to laser hazard.

- SR Alignment is ongoing, adjustments still need to be made today and possibly onto tomorrow.
- CO2X was able to get the extinction ratio to 10,000:1 with the AOM in. HWS work is up next. 
- Commissioning still ongoing, same thing as yesterday.
- SEI work in the staging building on going, the put on balance masses yesterday.
- Possible prep work for ACB and MCB build in the west bay starting soon.
- Water was off for a bit this morning.

Patrick Thomas, Thomas Vo

We checked the CoE parameters in the Beckhoff system manager and verified that they matched the same values as those for the PSL rotation stage.
We went out to the TCSX table and used medm on a laptop to move the rotation stage.
The rotation stage would move again, but not to the requested angle.
We power cycled the Beckhoff chassis twice. (We weren't sure we left it off long enough the first time.)
We tried to move the rotation stage again. It moved to the correct requested angle.
A motor warning was reported and the rotation stage would no longer move.
Thomas forced the motor warning variable in the PLC to FALSE, which allowed the stage to start working again.  It was decided in the code review that we will only stop the motor on motor errors not warnings.  The strange thing is that the motor is working pretty well now even if I don't force the warning to be false.  The long term solution to the problem of why motor warnings stop the stage is not quite figured out yet but it seems to be working now.  Also, we don't know why the stage was moving in opposite directions, but rebooting the chassis worked to fix the problem.


Interlock:
We noticed that the medm readback for the safety interlock indicated that the rotation stage was locked out, but it was still able to move and the interlock jumper has no effect on the status on the MEDM screen.  We think it's a problem with the Beckhoff wiring or software because we tested the continuity of the interlock signal in the on/off state (closed with jumper in, open with jumper out) from the floor all the way to the CER up till the Beckhoff chassis and it looked normal to us.  For now, we can just remove the interlock signal from the MEDM screens so it doesn't confuse people

model restarts logged for Wed 30/Apr/2014
2014_04_30 09:43 h1iopsusb123
2014_04_30 09:44 h1susbs
2014_04_30 09:44 h1susitmy
2014_04_30 09:46 h1susitmx

2014_04_30 10:30 h1isiitmx
2014_04_30 10:33 h1isiitmy
2014_04_30 10:35 h1isietmx
2014_04_30 10:36 h1isietmy
2014_04_30 10:38 h1isibs

No unexpected restarts. h1susb123 restart and ISI model development. No need for DAQ restart.

Kiwamu, Alexa, Stefan

We fine-tweaked the UIM drive template for ETMY:
  2014-04-30_H1SUSETMY_L1_L2PY_SweptSine_OLDamp_Off_5Hz2600mHz.xml
and ran it (with OL damping on, so the name is wrong...)
This one needs **SAVING** in the morning.

We also prepared
  2014-04-30_H1SUSETMY_L1_L2PY_SweptSine_OLDamp_REALLYOff_5Hz2600mHz.xml
and script-started it at 30 past midnight (after turning off OL).

Note that this one uses ISCINF as excitation point, so the two measurements could run in parallel, except off course that the OL damping will be switched off (not that it makes any difference below 0.3Hz.)
This one should auto-save once it finishes.

As a preparation for awesome ALS diff, I have loaded Jeff K's blend filters in M0, L1 and L3 stages in both ETMX and ETMY. They are currently in the LOCK filters. I followed the latest DARM design study described in:

sus/trunk/QUAD/Common/FilterDesign/HierarchicalControl/DARMmodel_ALS_20140428.m

(Aidan B, David H, Thomas V, Alastair H, Matt H)

 (Note this is talking about TCSx table)

So finally some success. The first polariser after the laser was moved from before the AOM to after the AOM (and positioned such that the transmitted beam from the AOM goes through the polariser but the first order beam does not). It was then quite easy to alter the polarisers so that I got a minimum power reflected of off the 2nd polariser after the Beckhoff controlled HWP of 4.5 mW when in CW mode (HWP setting of 36.4 degrees gave this maximum power). The power transmitted onto the high power, power meter was 44W. (see top drawing on attachment).

We now can begin aligning in earnest again. However as we want to start running the laser around the clock soon, we started putting some other provisions in place first.

• The manifold was modified so that we could use the water cooled beam dump and the water cooled beam dump is now positioned after the first polariser after the HWP, so we can now dump all the power there as designed.
• One of the quadrant thermopiles has been placed on an x,y, z, translation stage so we can start calibrating these quadrant thermopiles
• Temperature sensors were placed on the AOM, AOM drive, RF drive and the water cooled beam dump. One will also go on the manifold also once I get a bracket modified to hold the thermistor in place. To see these temperatures go to the main CO2 screen, click on the ethercat tab and you will see 6 temperature sensors (see pic 1 and pic 2). Temp sensor 1 is the AOM, Temp senosr 2 will be the manifold (not plugged in yet), Temp sensor 3 is the AOM drive, Temp sensor 4 is the water cooled beam dump, temp sensor 5 is the RF drive and Temp sensor 6 is a spare (not plugged in). I have asked that these be relabelled with something sensible (apparently names are generted in Beckhoff).
• We have started putting up laser barrier shields at the edge of the table near the laser

I also was going to put in the PD's that will be used for the Intensity stabilisation as they arrived today. However they dont physically fit. So we are going to have to come up with a different layout. Aidan is currently looking at what we will do. We also tried to put a breaker box supplied by Ben Abbott between the ISS box and the feedthrough. We had some issues with the connectors at the feedthrough working so we reverted back to the old setup. David was modifying so that we can try again tomorrow to connect this up

We have continued aligning after the polarisers and now have the 1st flipper mirror, lens and 2" steering mirror aligned. I thought this to be a good stopping point for the night as I am confident I can get the rest aligned tomorrow now. I have put a beam dump after this mirror to dump the beam into, so the laser can be started up at any stage if I am not here and all beams should be dumped. (see second drawing in attachment of sketch what done thus far).The Beckhoff controlled HWP has also been set to 36.4 degrees and so should dump the majority of the power into the water cooled beam dump.

Pic 3 shows the table layout as currently done

Pic 4 the water cooled beam dump (note hose clamp holds temperature sensor in place)

- Stood up CSD for H1LSCAUX, H1LSC, and H1ECATC1PLC2.
- Updated the xml files for H1LSC and H1ECATC1PLC2 to handle ALS and PRMI states.
- In particular, for the purpose of setting its control state, I split the LSC in four separate systems:
  - The IMC part (H1:LSC-IMC_STATE)
  - The central interferometer part (H1:LSC-PRMI_STATE)
  - The ARMS & ALS part (H1:LSC-ARMS_STATE)
  - The photo diodes (H1:LSC-PD_STATE)
- The xml file easily allows to merge them later or add more / different states.
- The H1:LSC-PRMI_STATE variable currently can be set to PRX, PRY or PRMI
- In addition there is a H1:LSC-PRMI_PD_SELECT variable, which has values of VAC_PD, AIR_PD and 3f_PD.
- In addition I added
  - H1:LSC-MISC_STATE and H1:LSC-PSL_STATE for some additional junk.
  - H1:LSC-MATRIX_LOADING, which punches H1:LSC-PD_DOF_MTRX_LOAD_MATRIX if set to automatic (or does nothing in manual)

One Warning:
 - I spent some time trying to make sure that the H1ECATC1PLC2 does not interfere with guardian or Beckhoff auto-locking. But it is possible that I missed some channels (since there is no channel declaration available in either). So if we have issues tomorrow, we should set H1ECATC1PLC2 into dryop mode and watch for differences.

A dtt measurement was started for the test mass to test mass L2L transfer function of ETMX (using ESD drive) on opsws2. It is saved under QUAD/H1/ETMX/SAGL3/Data/2014-04-30_H1SUSETMX_L3_L2LPY_SweptSine.xml
An other one was started on opsws6 for ETMY UIM

On monday night, we were able to measure the top mass to test mass L2L transfer functions on ETMy and ETMx, using the ALS-{X/Y}_REFL_CTRL signal for the response. The idea is to measure and invert the plant for each of the following stages (TOP UIM and TST).

We did the measurement in two configurations :

1- oplev damping feedback to UIM on
2- oplev damping feedback to UIM off

In both cases, the slow feedback was ON (using the inverted fit from the model) and the length to pitch and length to yaw decoupling filters were engaged (gain of -1).

The L2L measured plant is sligthly different when oplev is on/off. With oplev on, the Q of the first QUAD resonnance is higher.

The data was fitted for the 4 measurements (using the script fit_topLong2tstLong.m under QUAD/Common/FilterDesign/Scripts), and the inverted plant was installed in the LOCK filter banks FM1 (tuned for oplev damping on : "invL2L") and FM2 (tuned for oplev damping off "invL2L2"). The fitting is summarized in the attached plots.

The phase of EX measurement is off by 180 degrees for some reason.

The results were saved under
EY
/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMY/SAGM0/Data
2014-04-28_H1SUSETMY_M0_L2LPY_OL_OFF_SweptSine.xml
2014-04-28_H1SUSETMY_M0_L2LPY_SweptSine.xml

EX
/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMY/SAGM0/Data
2014-04-28_H1SUSETMY_M0_L2LPY_OL_OFF_SweptSine.xml
2014-04-28_H1SUSETMY_M0_L2LPY_SweptSine.xml

The higher temperatures pushed the 7805 of the EX CFC into thermal shutdown. We swapped the regulator, added a large heatsink and run without a lid. At a more opportune time we need to hammer in the copper heat pipe.

Some seconds after I and Arnaud started the EX ESD TF measurement, EX PLL failed. VCO frequency readback was giving some nonsense numbers like 65MHz and such (should be about 79MHz), beat note was going around 0, PDH modulation readback was also nonsense, and we were even reading some frequency out of unused ports.

Daniel was suspicious about the DC regulator (7805) thermally overloaded, because that chip is without any heat sink (and, as it turned out, it was not even screwed down to the board itself).

We went to the EX, shut it down, and after a while powered it up again, and it read the frequencies fine. We pulled the unit, Daniel swapped the chip and put a heat sink on it, which unfortunately made it impossible to put the top lid of the chassis, but anyway we left it like that for the moment.

After putting it in the rack, it seems like it's working fine again.

Note that a proper modification should be made to this unit later, as well as all 3IFO and spare units.

Conlog is back up and running and monitoring the channel list that Dave generated yesterday. I disabled the crontask that logs the disk usage and number of database rows because I know that the latter is a long query. I also disabled the MySQL binary logging that is used to report the frequently changing channels. I'm not sure if this has helped, the CPU usage for the conlog task is still at 100%. There is also a high I/O wait.

Attached is a plot of the queue size over the last two days. I stopped conlog when I found it high and plateaued yesterday afternoon. The queue size seems to take a while to come down after startup now, but it remains low afterwards.

(Sheila, Alexa)

We had thought that maybe the 1/f noise seen in COMM came from the PFD. Today we have ruled that out. We did this by replacing the PFD with the spare IQ demod channels of the IMC. In this confirgaution we measured the beatnote signal to be 250mVpp, and set the COMM PLL Input gain to 31dB. This resulted in a loop with -18dB less gain than the nominal configuration. We then used the control signal to measure the noise.

I have attached a DTT with the following traces:

• REF 2-3: signal with demod and input 1 gain 31dB (corresponds to UGF of ~3kHz)
• REF 4: signal with PFD and input 1 gain 27dB (nominal configuration corresponds to UGF ~30kHz)
• REF6: signal with PFD and input 1 gain 9dB (corresponds to UGF of ~3kHz)
• REF10: signal with PFD and input 1 gain 18dB

Clearly, the PFD does not seem to be the culprate. These measurements also suggest that we should lower the UGF of the COMM PLL loop.

With the demod in place and the input gain at 31dB, I also measured the amplitude spectrum out of the IMON of the demod. I have attached the data.