H1 SUS OFI Signal Chain Functional, Damping Loops Work, AOSEM Noise Is Good

J. Kissel, M. Pirello, R. McCarthy

Continuing along with the new HAM5/6 electronics adventure, we were able to make the H1 SUS OFI signal chain completely functional today. The electronics are final and as designed. As such, I was able to confirm that 
   (a) The suspension remains free after pump-down (yes!)
   (b) The damping loop design from yesterday works well (yay!)
   (c) The AOSEM noise floor is below spec / requirements (yeah!)

Attached are screenshots of the (newly taken) undamped transfer functions, (newly taken) damped transfer functions, and (newly taken) amplitude spectral densities.

%% Details %%
Undamped Data Files:
/ligo/svncommon/SusSVN/sus/trunk/OFIS/H1/OFI/SAGM1/Data/
    2018-01-19_2151_H1SUSOFI_M1_WhiteNoise_L_0p01to50Hz.xml
    2018-01-19_2151_H1SUSOFI_M1_WhiteNoise_T_0p01to50Hz.xml
    2018-01-19_2151_H1SUSOFI_M1_WhiteNoise_Y_0p01to50Hz.xml

Damped Data Files:
/ligo/svncommon/SusSVN/sus/trunk/OFIS/H1/OFI/SAGM1/Data/
    2018-01-19_2312_H1SUSOFI_M1_WhiteNoise_L_0p01to50Hz.xml
    2018-01-19_2312_H1SUSOFI_M1_WhiteNoise_T_0p01to50Hz.xml
    2018-01-19_2312_H1SUSOFI_M1_WhiteNoise_Y_0p01to50Hz.xml

How we made it work:
(1) The OFI's coil driver is *not* an ISC configuration HAM-A driver chassis (No chassis drawing exists, only front and back panel drawings; see complaints about that in LHO aLOG 8772), it's a regular ol' HAM-A driver (D1100687)-- but both use the HAM-A board D1100117. That means we'd forgotten to jumper the "Test/Coil Enable" switch. That means out OFI's DAC drive wasn't making it into the coil driver circuit. Richard realized this and had Marc pull the chassis and jumper the appropriate pins on the board. While at it, we made the executive decision to jumper the Lowpass Filter ON as well, such that it behaves identically to an ISC configured HAM-A driver.
(2) The drawing for cable arrangement on the vacuum flanges of HAM5 (D1002876-v4) is not up-to-date. As such, I discovered (after driving ZM2 with the OFI signal chain!!) that ZM2 and OFI cables were swapped at the vacuum flange, because whomever installed them couldn't possibly have known. We now have the cables correct, and 
   - ZM2 (on cable SUS-SQ-21) is plugged into 
      - Conflat D3 (the furthest +X, on the beam splitter side of HAM5), 
      - Flange 2 (lower left, if you're looking at the chamber from the air side with the beam splitter to your back)
      - Connector 2 (the bottom DB25)
   - OFI (on cable SUS-SQ-30) is plugged into
      - Conflat D3 
      - Flange 3 (lower right, if you're looking at the chamber from the air side with the beam splitter to your back)
(3) I had not yet installed the proper COILOUTF driver electronics frequency response compensation (primarily because there's an innocuous bug in the coil driver state machine code, 'cause it was built for a 4 OSEM system, and we're using it here on a 3 OSEM system).
Having fixed those three problems -- we're good to go!

Ops Day Shift Summary

SDF failing for CS ECAT PLC4

The process segfaults at startup.  The reason appears to be an enum that went out of bounds.  It was requesting a description string that did not exist.  This appears to be an issue only when the connection is first made and a determination is made if the enum should be treated as a string or a numeric value.

See FRS https://services.ligo-la.caltech.edu/FRS/show_bug.cgi?id=9749

I branched the advLigoRTS code and implemented a fix.  It is being tested on the h1sysecatc1plc4sdf.

The h1sysecatc1plc4sdf is running.

WBSC2 H1 BS HEPI Stroked in Z to test IPS range--Local Checks for Mechanical Limits

Attached are trends over an hour where the BS HEPI actuators were driven individually to look for limits.  The plot is likely only useful for me but it does contain the local sensors and the OUTPUT drive and the Z location_mon.  I've zoomed into the X-axis of each corner during that corner's drive, hence the screwed up DV x axis.  Anyway, it shows some clipping and limits but again mostly for me.  I drove sine of various amplitudes.

In the end the IPS should have good signal to +-1mm but the signal is better the closer it is to zero.  The mechanical limit of the Actuator is design to be 1.375mm and the sensor gap is 1.625mm.  So best to have the IPS operating at zero but you can't just zero it out where you sit.  If the platform has sagged for some reason you can get close to the mechnical limits and if you muck about too much with the sensor position, the sensor can be put in jeopardy.

The take away is the following:

V1--Appears to be hitting a mechanical limit at +22K (~0.8mm) and is reaching the IPS limit at -32k counts.  Suggests the actuator could be lowered and/or have the IPS rezero'd, but really, the range is fine.

V2--With the sensor centering I did yesterday, V2 is moving freely for +- 1.1mm, plenty of range.

V3--This sensor is showing some sign of clipping at 0.4mm but I think these signs are just showing how the V4 limits impact the other (mainly corner 1 & 3.)  Should repeat after V4 is fixed.

V4--Despite the closeness of the mechanical stop on this corner (see last photo on alog 40171) the corner is still moving about 0.8mm.  This test isn't good for performance evaluation and I'd still like to do the Actuator reset to make sure we are not too close.

Closing WP 7297

PT-120B noisy

Cold cathode pressure gauge (PT-120) read back is noisy starting ~ 11 UTC (3am local) on Jan. 18th. Not sure why.

Primitive Damping Loop Design for New H1 SUS OFI OSEM System

J. Kissel

I've designed and installed some primitive damping loops in the H1 SUS OFI's DAMP bank. I mocked up a plant model in Foton using the in-air measured data from LHO aLOG 39033,  copied over some basic filters from the OMs, and had foton model the open loop gain of the loops. Without any requirements or specifications, I've arbitrarily chosen a loop gain of ~5 around the resonances as a start. Once we get all electronics figured out, I'll characterize the new loops via measurement and adjust the gain / design accordingly.

Design details:
H1:SUS-OFI_M1_DAMP_L: 
    FM1 (0:100,100) -- a complex pair of poles at 100 Hz with a Q of 0.87 between them
    FM5 (cheby5) -- a 2nd order Chebyshev low pass, with a 5 Hz corner frequency and 2 dB of pass-band ripple
    FM6 (gain) -- a x200, gain only "filter"
    FM9 (PendL) -- [DO NOT USE] the plant model, to be used for offline design assistance only

H1:SUS-OFI_M1_DAMP_T:
    (Same as L, but the FM6 gain "filter" has a value of x4000)


H1:SUS-OFI_M1_DAMP_T:
    (Same as L, but the FM6 gain "filter" has a value of x50)

Conlog crash on attempted insert of invalid JSON text

Same issue as reported in alog 40054.

TCS{X,Y} beam samplers

Images of the TCS{X, Y} beam samplers.  Look okay.  Slight damage on the TCSX one at around 4:30 in the attached image.  Could be schmutz.  Not near the centre of the optic.

HAM2 East door camera not yet installed, changes to the IM alignment, and signals

• the HAM2 East door analog camera is not installed, the camera housing is there, but no camera inside, lenses I currently have are not working out to give enough field of view and clear focus, mount inside the housing was moved for one camera lens, but needs to move back more to center
• looked at IM alignment, meant to reset, highlights of how the alignment was left
• IM alignment, different based on IMC differences (in-air2now), IM4 Trans, beam at PR2, and light on QPDs
• looked at alignment downstream, image below has two beams at/on the SRM baffle (upper left and lower right), investigating meant beams were much less obvious when I left (center spot never moved, maybe OSEM light?)
• no snapshot of the alignment, and can't recall IMC changes in slider values, but 1 slider count = 0.05urad, and the total ideal range of the IMs is 120000 slider counts, which is a change of +/-3mm at 1 meter from the optic, which doesn't account for IM curved mirrors, but is a staring point for approximating the change

Diode box 1 current increased

Increased the diode current for DB1 from 60A to 63.5A and adjusted the temperature of diode 3.  Laser power went from ~152 W to
~187 W as reported on the Beckhoff screen.

After Many Moons -- H1 SUS OM1, OM2 and OM3 OSEM Systems are Functional Again

J. Kissel, M. Pirello

Marc and I sat down with the mess of wiring diagrams today (see below) in order to verify that all cables had been connected and chassis have been turned on after the several month delay in re-arranging and installing the HAM5/6 suspension electronics due to vent activity. We found a few chassis not turned on, and a few cables in the wrong place, but those problems were easily rectifiable. I've now begun the verification process that all is well with that which are easy: the OM1, OM2, and OM3. 

I had to flip the sign of the damping loops from -1 to +1 (now captured in the safe.snap SDF file), but now all damping loops are functional. I've confirmed so by taking damped M1 to M1 transfer functions, which look clean and healthy, regardless that HAM6 is still at air and the ISI and HEPI are locked. I attach screenshots of the L to L transfer function, though I took all three DOFs. I'll process them fully in due time (likely once we're closing up HAM6).

Next up -- ZM2 and OFI.

%% Details %%
Drawings used to identify cable names (which have three different naming schemes):
For SUS SR3, SRM, and OMC: D1002740-v6
For OM1, OM2, and OM3: First Sheet of D1200666-v11
For ZM1, ZM2, VOPO, and OFI D1700384-v6
For ADC / DAC connections and assignments for all of the above D1002740-v7

Data files:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/
    OM1/SAGM1/Data/2018-01-19_0101_H1SUSOM1_M1_WhiteNoise_L_0p01to50Hz.xml
    OM1/SAGM1/Data/2018-01-19_0101_H1SUSOM1_M1_WhiteNoise_P_0p01to50Hz.xml
    OM1/SAGM1/Data/2018-01-19_0101_H1SUSOM1_M1_WhiteNoise_Y_0p01to50Hz.xml

    OM2/SAGM1/Data/2018-01-18_0102_H1SUSOM2_M1_WhiteNoise_L_0p01to50Hz.xml
    OM2/SAGM1/Data/2018-01-18_0102_H1SUSOM2_M1_WhiteNoise_P_0p01to50Hz.xml
    OM2/SAGM1/Data/2018-01-18_0102_H1SUSOM2_M1_WhiteNoise_Y_0p01to50Hz.xml

    OM3/SAGM1/Data/2018-01-19_0102_H1SUSOM3_M1_WhiteNoise_L_0p01to50Hz.xml
    OM3/SAGM1/Data/2018-01-19_0102_H1SUSOM3_M1_WhiteNoise_P_0p01to50Hz.xml
    OM3/SAGM1/Data/2018-01-19_0102_H1SUSOM3_M1_WhiteNoise_Y_0p01to50Hz.xml

Processed this data in detail finally. See attached. 

Note that this data was taken before the sign convention was identified as wrong for all HTTS in LHO aLOG 40847, so the phase does not agree with the model at DC by 180 deg. This has since been fixed, see LHO aLOG 40853 though I haven't yet retaken TFs that demonstrably confirm that all is well. We'll do so once we're closer to closing HAM6.

Also note that the individual measurement results have been processed by a revamped 
    /ligo/svncommon/SusSVN/sus/trunk/HTTS/Common/MatlabTools/plotHTTS_dtttfs_M1.m
which plots the EUL drive to OSEM response correctly for the first time, and the plotall script,
    /ligo/svncommon/SusSVN/sus/trunk/HTTS/Common/MatlabTools/plotallhtts_tfs_M1.m
respects the phase.

ISCT6 Detector calibration

Daniel, Sheila, Nutsinee

Nominal laser output power measured (with a PDA100A) as 18 mW through a 98% beam splitter (Rp 98%). Transimpedance=1500 Ohms, responsivity=.221A/W (variable gain setting on PDA100A set to 0dB).

Green output power measured (with a PDA100A) as 2 mW through 95% beam splitter (~100mW IR -> 40mW green). Transimpedance=1500 Ohms, responsivity=.313A/W (variable gain setting on PDA100A set to 0dB).

NewFocus 1611 detector to lock laser to PSL: Beat frequency signal measured with spectrum analyser ~ -14dBm at 155MHz as measured from the -1dB coupled output on the TTFSS pre-amp. Note there is a signal decrease by around 5dB with large (squeezing) laser frequency shifts (~500MHz or more) that seems to be due to beam pointing errors on the 1611 detector. However locking signal depends on phase and is largely insensitive to amplitude fluctuations so we should be ok. Responsivity=.75A/W, Transimpedance=-10k Ohm, gain setting 0, Voltage = -1.6V.

Power to 1611 detector: .30mW from PSL + .67mW from sqz laser -> .49mW on detector after 50/50 beam-splitter. MEDM screen reads .21mW ?? If the transimpedance is adjusted to -5k Ohm MEDM screen reads correct, but I suspect something is still odd about this. 

Fibre (PSL) power rejected = 1.3 uW measured with a PD1A detector (2 K impedance).

Fibre (PSL) power launched = 27 uW measured with a PD1A detector from a 10% beam splitter. Disabled gain selection setting (alog 40161) has been corrected. Note the beamsplitter was changed from 2% transmission in the original drawing (BS8) to 10% transmission.

TCS CO2Y laser tested

Turned the RF driver and the power supply on for the CO2Y laser, also connected the IR sensor, and was getting green lights for the control board. Using the PWM controller I tried to turn the laser on but wasn't getting any results on the power monitor. After double checking the power supply was set to 28V and 28A limit, and the RF driver was set to 40.68MHz, Fil and I found that the wrong RF cable was plugged in. After plugging the right one in the laser powered up in PWM mode and I was able to verify the rotation stage is working as well. Tomorrow I will check that the alignment hasn't changed significantly and that the periscope picomotors are operating correctly.

H1SUSSRM RT SD OSEM Sensors were Dead -- Now Fixed

J. Kissel, R. McCarthy, M. Pirello

While trying to finally get around to finishing out the MEDM infrastructure for the new SQZ suspensions and the re-arranged OMs, we discovered that the RT and SD OSEMs are dead on SRM. They apparently died on Jan 10 ~19:30 UTC (about 11:30a PT). Remember, we know the problem is highly likely out of vacuum, since I was able to take successful transfer functions on Jan 3rd (LHO aLOG 40002). Much more likely -- Gerardo's Vacuum work mentioned in LHO aLOG 40090, or Fil and Liz's cable pulling mentioned in LHO aLOG 40085)

After tracing and confirming integrity and correctness of all HAM5/6 SUS cables from the AA chassis to the remote satellite amplifier, I noticed that two of the SRM (T3 LF RT SD) sat amp fault lights were on (see attached picture). Power cycling the respective SRM T3LFRTSD coil driver chassis didn't find the problem.  Talking with Richard, he suggested it was the last cable run from the sat amp to the chamber, since it's a tight squeeze getting the cable to seat properly at the feed through.

As suspected, he went out to diagnose and was able to wiggle the connection at the feed through enough to intermittently restore life to RT and SD, but didn't have the right tools to really make the connection secure, so he (or Fil) will finish out the fix tomorrow morning.

J. Kissel, R. McCarthy

Ran a (damping loops closed) set of top mass transfer functions for a health check after Richard has properly seated the cable. Functionality appears to be completely restored. Nice work!

I haven't exported and properly processed the data yet, but the data files are committed to the SVN here:
    /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SRM/SAGM1/Data/
        2018-01-19_1618_H1SUSSRM_M1_WhiteNoise_L_0p01to50Hz.xml
        2018-01-19_1618_H1SUSSRM_M1_WhiteNoise_P_0p01to50Hz.xml
        2018-01-19_1618_H1SUSSRM_M1_WhiteNoise_R_0p01to50Hz.xml
        2018-01-19_1618_H1SUSSRM_M1_WhiteNoise_T_0p01to50Hz.xml
        2018-01-19_1618_H1SUSSRM_M1_WhiteNoise_V_0p01to50Hz.xml
        2018-01-19_1618_H1SUSSRM_M1_WhiteNoise_Y_0p01to50Hz.xml

Corresponds to FRS Ticket 9744.

Laser trip

Richard informed me that the laser had tripped this morning.  I reset the laser without any problems.

    I increased the current for head 1 to the maximum of 60A and increased the diode temperature for
diode 3 to 23 degC.  The output of diode box 1 has taken a bit of a dive since the weekend.  So much
so that I would start to become concerned that the thermal lens in the NdYAG rod isn't what it should
be to make the resonator stable.

    At this point in time, we have two options as I see it, depending on commissioning constraints:
  i. replace the diode box
  ii. revert to low power mode
Both would take about half a day to do.

I have not turned the power watchdogs back on.

The power of diode 3 in DB1 has dropped by 50% of its original power. The TEC is already at the maximum of its performance.
You should lower the temperature further and observe the performance of the HPO.
The current for the diode boxes can be higher than 60A, if you enter the value directly and do not work on the plus and minus button.
The diode itself will not last much longer.

RF Amp measurement

Daniel, Nutsinee

Here's a quick note of what we measured out there with the RF power coming in through (and monitored via) temporary cables. These RF power drive AOM1 and AOM2. There seems to be too much loss at Pmon2 compared to Pmon1 (almost 11 dBm loss versus 5dBm loss). The cable length going from CPL to Pmon are the same. The top RF input gets its power all the way from the CER while the bottom RF input gets its power from the SQZ rack. So the difference in the incoming RF power makes sense. Not sure if the factor of two difference coming straight out of the Cpl makes sense though.