A very long time ago, Brian Lantz wrote a technical document describing how to design filters to compensate BSC stage 1 drives for the forces applied by the stage 2 actuators ( T1600138 ). Over the last month+ I finally got around to figuring out how to actually make and install the filters. I've now installed these filters on every chamber, but it took me a while to figure out if they were doing any good. Today, I just took some transfer functions driving stage 2 and looking at the stage 1 sensors. After I figured out the sign, it looks like stage 2 drive compensation on stage 1 works.

First attached plot shows ITMX X dof for both stages, and it's hard to look at just the asds and say that the compensation is doing anything. I've taken a number of spectra on different chambers and it looks during normal operations we wouldn't see much of a difference. But when I put extra drive on stage 2, it looks like the coupling from stage 2 drive to stage 1 motion is reduced by about an order of magnitude, up to 100 hz. Second plot shows the transfer function from stage 2 drive to stage 1 l4cs and stage 2 gs13s. The 3 configurations I tried were compensation off (blue traces), compensation on with +1 gain (green traces), compensation on with -1 gain (red traces). I also tried a gain of -1.5, but this made this worse, so I think the magnitude is right, I just need to fix the sign in the matlab script I used. The dashed lines show that the stage 2 drive to stage 2 motion transfer function doesn't really change, which is good to know. My drive was mostly over 10-30hz range, so that's why the tf gets ratty below 10 hz.

I wrote a barebones function to do the filter design, so if LLO wants to do this, its pretty simple. The function takes one of the calculated damped plant frd's from the ISI commissioning data, a vector of zpks, and some other plot flags and makes plots like the third attached image. After doing the fits for the first chamber, I basically didn't have to do tweak the filters at all. There are features around 9hz that I'll probably remove on a second round when I fix the signs, because I don't think they help. I haven't checked, but I suspect there might be small gain differences between chambers, but the script does that gain matching on it's own. 

I'm curious as to what effect this will have on the BS during mich locking. I worry that I'll have to turn the compensation off on that chamber, but maybe this will allow the stronger stage 1 actuators to back up stage 2?

TITLE: 01/24 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:
LOG:

16:13 Terry out to squeezer bay

16:18 Karen and Vanessa out to EY to clean

16:39 Fil out to HAM2 area - camera images not getting into cr

17:00 Vanessa and Karen back from EY

17:10 Mark and Tyler out to MX to retrieve magnets

17:12 Travis, Danny, Angus and Karl (welding crew) out to EY

17:20 Jason out to PSL enclosure.

17:27 Karen and Vanessa cleaning in LVEA

17:30 Marc out to LVEA - ZM work at output arm

17:31 Fil out

17:51 Jeff B heading out to PSL enclosure - leak in chiller manifold

18:10 Jason back from PSL enclosure and out to EY for Fiber Welding.

10:32 Sheila out to optics lab

19:06 Mark and Tyler back  and out to LVEA - moving ION pump

19:08 Peter going out to PSL enclosure - to secure environmental controls after leak repair is done

20:00 Welding crew and Sheila back and out for lunch

20:30 Peter ad Jeff B out to ITMX - camera

21:05 Peter and Jeff back

22:00 Site Meeting

While the PSL was down this morning, we took the opportunity to reboot Corner 4 and Corner 6 EtherCAT chassis.  This was to determine if a reboot would fix bad readbacks described in this ALOG 40152  In the case of the H1 SQZ 42.375 MHz the reboot was successful in restoring the signal.  In the case of ASC-AS_B_RF42_DEMOD_LOMONCHANEL_3/4 it did not work, the offset is still present.  The plan now is to swap the beckhoff terminal in Corner 4 when a clear opportunity arises.  Until then I will leave WP 7309 open.

J. Kissel

As one of the final steps to completing the re-arrangement of the HAM56 suspension electronics systems, I've copied over the latest filter files for H1SUSOMC, H1SUSOPO, and H1SUSHTTS to the userapps repo, and created new softlinks from the chans directory to the userapps repo for the HTTS and OPO filter files.


$ pwd
/opt/rtcds/lho/h1/chans
$ cp H1SUSHTTS.txt /opt/rtcds/userapps/release/sus/h1/filterfiles/
$ cp H1SUSOPO.txt /opt/rtcds/userapps/release/sus/h1/filterfiles/
$ svn ci -m "Committing new filter file structure after the SUSHAM56 rearrangement." /opt/rtcds/userapps/release/sus/h1/filterfiles/H1SUSOPO.txt H1SUSOMC.txt H1SUSHTTS.txt
$ ln -s /opt/rtcds/userapps/release/sus/h1/filterfiles/H1SUSOPO.txt H1SUSOPO.txt
$ ln -s /opt/rtcds/userapps/release/sus/h1/filterfiles/H1SUSHTTS.txt H1SUSHTTS.txt

Created:

(userapps)/sus/common/guardian/SUS_ZM2.py

(userapps)/sus/common/guardian/SUS_ZM1.py

And then I had to add in a few lines in (userapps)/sus/h1/guardian/sustools2.py:

1457: zm1wd = dict(httswd); 

1458: zm2wd = dict(httswd);

...

1491:    ('H1','ZM1') : {'type': 'HTTS', 'watchdogs': zm1wd},
1492:    ('H1','ZM2') : {'type': 'HTTS', 'watchdogs': zm2wd},

Jeff K cycled through a few of the states and it looks good. Shouldn't need much testing since it is all the same tip-tilt code. The DAQ will need to be restarted to get the new channels. ZM1 is ready to be created and started whenever the suspension is ready.

J. Kissel, R. McCarthy, M. Pirello
FRS Ticket 9771

After solving all of ZM2's signal chain problems (all of which were mis-jumpered boards inside its new HAM-A coil driver and US Sat Amp, see LHO aLOG series starting with 40237), I'd accidentally told Marc to jumper the SatAmp to the AOSEM setting (ZM2, an HTTS, uses BOSEMs). He's jumpered it to the BOSEM setting this morning, so I've taken another diagnostic suite. 

Turns out, though the OSEM sensor response dropped by an inconsequential ~13%, ZM2's BOSEMs don't care whether they're read out with a Sat Amp jumpered in the AOSEM or BOSEM configuration. 

Richard and I recall that perhaps all US sat-amps are jumpered to the same configuration, because (as Richard specifies) one species of OSEM doesn't use the feature implied in that configuration, it just needs to be jumpered to either/or. So we recall having set all US sat-amps one way (or the other). We'll figure out which (by checking the OMs and RMs), and set all the new US Sat Amps (for OFI, ZMs, and VOPO) the same way.

For all intents and purposes, ZM2 is now fully functional.

Every few months, I run into issues writing filters from my designs in Matlab to the foton file. This is usually because Matlab decided that it can't find some critical file.  Dave summarizes one case of this in alog 36594. Yesterday, in the middle of a session(i.e. after I had successfully written a couple filters), Matlab again decided it couldn't some new critical files (in the same location as the libc file from Dave's alog). No idea what changed, autoquack just stopped working, complained it couldn't find 2 files it needed. I tried 2 versions of matlab (2015 & 2016), tried changing the launch options. Eventually, I found Keith's comment to Dave's alog. After I found where he put his linux.m (he means userapps/cds/utilities/, trunk did not have an obvious meaning to me) I added that to the path and tried running the autoquack_foton_cleaner system call that kept failing (i.e. linux('foton -c ...') instead of system('foton -c ...') and it worked.

For now I've made new versions of autoquack and autoquack_foton_cleaner, called autoquack_linux and autoquack_foton_cleaner_linux, that use linux.m instead of the system or unix calls. These aren't in the SVN, cause this fix is kind of dumb.

Alternatively, I've put an addpath to linux.m and a call to do a linux('something') to a shortcut I use all the time in matlab. Just running linux('something') is enough to fix the paths and make the unmodified autoquack work.

Y1 beam tube pressure improved after spinning up mid-Y main turbo pump (with its GV closed). Before starting turbo, the turbo inlet pressure read ~ 1 Torr, so its GV leaks. We have new valves on order, but vendor keeps delaying delivery. Hope to replace this valve in early Feb.

This morning I saw that Ed had added 350 mL of water to the PSL crystal chiller; Peter had added 200 mL of water to the crystal chiller yesterday.  This is much more than is usually required for regular chiller filling, so after discussing this with Jeff B. and Peter, I went into the PSL enclosure to look for a leak.  Sure enough, there are 2 leaks in the PSL water manifold; a slow one where the supply water line attaches to the input of the manifold, and a quicker one where the return water line attaches to the manifold output.  The PSL and chillers are now turned off, and Jeff B. is in the enclosure fixing the leak.  Once this is done the chillers will be turned back on to test the fix; if the fix holds, the PSL will be restarted.

The 50:50 BS (BS9) on the paths combining the Sqz laser and the PSL has been changed to an 8:92.

The 8:92 (BS5) on the path seperating the LO from the PSL has been changed to a 50:50 (we may have to increase the LO power but there is plenty of optical power to play with as 200mW is dumped early in the optical path).

We now have .3mW from the PSL and .7 mW from the Sqz laser incident on the beat-note detector, which is double what we had before.

Full updated schematic and parts list to follow shortly.

Elevated but coherent noise at ETMY probably due to work being done at this time.

16:20UTC I added 350ml of water to the Xtal chiller. THe level alarm on the unit was sounding off.

Attached are the VPW desiccant plots with this month's added data.  Nothing out of the ordinary shown since last months replacement of batteries in the sensors.  

TITLE: 01/24 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    Wind: 4mph Gusts, 3mph 5min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.40 μm/s
QUICK SUMMARY:

16:00 6.2 EQ in Japan showing on BLRMS‌ (approx)4.5 hours ago

17:55 King Soft on site (someone else opened the gate. I was behind them)

J. Kissel, M. Pirello
FRS Ticket 9771

(EDITED -- we confused ourselves: it's the US SatAmp that isn't reading out ZM2 correctly, not SUS-SQ-21 cable as originally suspected)

After identifying and fixed that ZM2's HAM-A driver has not been properly jumpered (see LHO aLOG 40218), we still are chasing down why we see so little ADC voltage from the OSEM sensors, and why the OSEM spectrum looks so poor in performance. 

After playing the "swap the cable connections with a known working chain at every connection of the whole chain" game, we traced the problem down to the cable between the SatAmp and Chamber feedthrough; SUS-SQ-21 the US SatAmp reading out the ZM2 OSEM chain (see wiring diagram here D1700384). 

The nail on the coffin is attached: we read out ZM2 from the chamber feedthrough with the OFI's ex-vacuo cabling (its equivalent "last cable on the way to the chamber" is SUS-SQ-30) and electronics -- and vice versa -- we see full, normal levels of ~15000 [ADC ct] of DC OSEM sensor voltage on the three OSEMs that the OFI digital system can read out, and we see low, junky DC OSEM sensor voltages on the three OFI OSEMs.

Throw that cable SatAmp in the trash, I say!

Jenne, Thomas, Sheila

The message is that we don't think that we need to move the OMC to have OK clearances in HAM6. 

• This morning Jenne and Thomas used a card to find positions of SR3 and SR2 which were roughly centered in the Faraday apperature (by moving both optics until they could not find a beam).
• Cheryl and Jeff measured 5.34 W of power going into the IMC from inside the PSL, while the IMC_PWR_IN diode was reporting 6W.  Thomas is updating the calibration. 
• We measured 11.4 mW in HAM6, so with 5.34W of input power, 80% IO throughput, 0.03% PRM transmission, 0.25 from the beam splitter in single bounce, and SRM transmission of 0.32, we expect 10.3 mW in HAM6.  If all these numbers are correct, it could be a problem with our power meter calibration.  We can try to repeat this measurement in HAM6 with the same power meter as was used in the PSL.
• We roughly aligned the path onto AS_C by steering all three of the steering optics, and translating the lens closer to OM1. 
• Once AS_C was aligned we closed the SRC2 loop from AS_C to SR2, and steered SR3 to find the edges of the aperture by watching AS_C_SUM.  We centered ourselves in this aperture with the alignment sliders as shown in the screenshot.
• We then returned to HAM6 and measured clearances and beam centering on the OMs. 
  • The beam from HAM5 is ~27mm from the edge of the OM2 cage, and centered on OM1 within a mm.
  • The lens in the AS_C path has plenty of clearance, maybe about an inch.
  • The spot on OM2 was 9 mm from center in the +X direction.  We rotated OM1 to center this better.
• • Before the OM1 rotation we had 8-9mm of clearance from the HAM5 beam to the fast shutter structure, but after rotating OM1 we estimate that we should now have 12-13 mm of clearance.  We have left the fast shutter out of the path for now since we do not have high voltage in HAM6 to open it.
  • The OM1-OM2 beam was 25mm from the OM3 cage when we started, and should now be larger.
  • We rotated OM2 to roughly center the beam on OM3's aperture, and saw that the beam is entering the hole in the OMC shroud.
• Still to do on HAM6 (not in order):
  • Reposition beam dump after OM2.
  • Put fast shutter back in path.
  • Dress fast shutter wires (llo log 37301)
  • Align onto OMC QPDs (might require removing shroud).
  • Double check AS_C beam path is centered on optics.
  • Use viewport simulator to check AS air beam position.