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Section: H2
Task: PEM
I made a new medm screen for the dust monitors so there's a single screen where you can see all of the particle counts for the site, and you can get to all useful dust monitor screens through this screen. I also added some shell command buttons to launch scopes of the individual DMs. Its located under PEM on SITEMAP.
Closes FAMIS 27648, last checked in alog 88314
Trends look fine!
WP12901. Daniel, Jeff, Oli, Fil, Marc, Jonathan, EJ, Tony, Dave:
Summary:
Yesterday I replaced h1iscex's 18bit-DAC with a 20bit-DAC as part of the project to eliminate all 18bit-DACs from production. There is currently no indication that the 20bit-DAC is driving the AI chassis with any voltage, investigation is ongoing.
Details:
The 18/20 bit DACs use the same interface card, so for the upgrade I was able to pull the IO Chassis out half way with cables still attached to access the PCIe bus. I removed the old 18bit-DAC and replaced it with on of the 20bit-DACs from h1susex upgrade
| old 18bit-DAC (removed) | 110425-03 |
| new 20bit-DAC (installed) | 190219-10 |
I do not know if the 20bit-DAC from h1susex was the one driving the PI or the one which had been idle since the LIGO-DAC went in mid 2024.
The original interface card and ribbon cable were reused. No field cabling was disconnected, no AI chassis were powered down.
Upgrade was done between 12:00 and 13:00 Tue 02dec2025.
Later that afternoon Tony found that the PCAL readbacks were not responsive. Tony and I went to EX around 17:00 to verify the 20bit-DAC was installed and connected correctly, it was.
This DAC has a special AI Chassis, D1101785 "aLIGO 18 Bit AI Chassis" which has handy BNC pickoffs for all 8 channels. We put a scope on the two channels being driven by h1calex (6,7) and could see no signal.
Also the last channel on the AI is loop-backed to the first ADC AA chassis with a DB9 cable, and the IOP is configured by SDF to drive the duotone from DAC0-chan7 back to ADC0-chan30. No signal is seen there either since the upgrade.
DCC docs for "18bit AI Chassis"
D1101785 [front section]
D1200316 [whole chassis]
The "AI WD" green LED on the rear panel is ON when the serial cable from the DAC Interface cable is connected and OFF when the cable is disconnected, suggesting the DAC is driving the WD line correctly at least.
Model changes:
h1iopiscex (Dave) updated to new DAC configuration
h1calex, h1pemex (Jeff, Oli) updated to new DAC configuration
All models on this front end, including h1iscex and h1alsex, were built and installed with RCG-5.5.2
Tagging CAL and PEM because this is "their" DAC.
We've done the typically thing with a DAC upgrade:
- the DC calibration of the DAC has changed from (roughly) 20 / 2^18 [Vpp_differential / ct] to (roughly) 20 / 2^20 [Vpp_differential / ct]
- Such that upstream control systems "don't have to be retuned" we apply a digital factor of (exactly) 4.0x to all output signals for each DAC channel
As such, for example, the calibration of the PCAL actuation / excitation chain is likely now slightly different, and should be remeasured.
At some point within the last year, both the X and Y-axis accelerometers (PEM-CS_ACC_LVEAFLOOR_HAM1_X and Y) were kocked off (pictured here) the small metal cube they were mounted to. I reattached them as of Nov 11, 2025. I believe the capacitor position sensor box was pushed back into the accelerometers which knocked them off. Image 3 shows where the CPS box is in relation to HAM1 (circled in red) and image 4 shows where it is in relation to the accelerometers.
Additionally, two other accelerometers have been remounted with epoxy in August: PEM-CS_ACC_BEAMTUBE_SRTUBE_X (remounted August 5, 2025) and PEM-CS_ACC_BEAMTUBE_YMAN_X (remounted August 12, 2025). Both had fallen off the beamtube and had been hanging in the air for an unknown amount of time until someone noticed.
The HAM 1 floor accelerometers appear to have been moved on or around April 18, 2025 during the HAM1 work during the break between O4c.1 and O4c.2. The coherence between the two signals dramatically changes character after that date. I attach some plots of the coherence between accelerometers the day after you repositioned them, as well as data from 0000-0100 UTC on a few example days. I'm not sure that it was moved exactly on April 18, but the coherence data begins to differ from the reference on that date.
Famis 27573 Vibration Sensors To Gauge Health Of HVAC Fans Site
H0:VAC-MR_FAN6_170_1_ACC_INCHSEC seem to be going up in that few days especially the last 24 hours.
This is also the case for H0:VAC-MY_FAN2_270_2_ACC_INCHSEC in the last day saw a fairly large increase in noise.
Closes FAMIS 27572. Last checked in alog 87988
MR_FAN1_170_1 and MR_FAN1_170_2 were increasing rapidly and approaching the cutoff of 0.7, but it appears they were turned off last Tue during maintenance (Ryan C reports that he and TJ saw this and told facilities). This was also reported in the last FAMIS alog for these fans. Counts are 0 for this plot.
MR_FAN6_170_1 is increasing very slightly but still under 0.2 cts.
All other fans look good. Plots attached.
TITLE: 11/14 Owl Shift: 0600-1530 UTC (2200-0730 PST), all times posted in UTC
STATE of H1: Microseism
OUTGOING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
SEI_ENV state: USEISM
Wind: 5mph Gusts, 3mph 3min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.86 μm/s
QUICK SUMMARY:
Eve shift had left the IFO in Idle to wait out the higher useism.
I woke up at 2am to see if the useism was low enough to lock since it was falling.
H1 went through an Initial Alignment before trying to lock, which took longer than expected locking the green Arms.
Once that was done I allowed DRMI to try to lock a handfull of times. I think when it fails this time I will leave it in idle and try again in a few more hours.
Last checked in alog87617, Closes FAMIS27430
The OUT building fans look the same as during the last check.
The CS fans, MR_FAN1_170_{1.2} look to be ever so slightly increasing in motion over the past 3 days, the rest look just as they did during the last check.
Last checked in alog87549, closes FAMIS27429.
There are a few noisy outbuilding fans, EY_470_1 and MX_370_1 are the worst offenders with ~ 0.3. MY_270_{1,2} see some sporadic noise increases everyday or less.
For the corner station fans, MR_FAN1_170_{1,2} have gotten a bit noisier 2 days ago, MR_FAN6_170_1 has also gotten a bit noisier the over past day. The winner of noisiest fan in the CS is MR_FAN5_170_1 at around ~0.4.
TITLE: 10/27 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 148Mpc
OUTGOING OPERATOR: Ryan S
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 8mph Gusts, 3mph 3min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.26 μm/s
QUICK SUMMARY:
Got the rundown from RyanS with H1's status (which has been good even with the EQs), it has been locked 3.5hrs. Microseism has leveled off (between the 50th & 90th percentile lines, after it's fast downturn yesterday), and winds lare calm.
Operator Checksheet NOTES:
WP 12850
Chassis found with positive 15V LED powered off. Side rack 1A fuse was blown. Replaced shorted C12 capacitor on the first D070081 board. Chassis reinstalled.
TITLE: 10/21 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Preventive Maintenance
OUTGOING OPERATOR: Oli
CURRENT ENVIRONMENT:
SEI_ENV state: USEISM
Wind: 4mph Gusts, 1mph 3min avg
Primary useism: 0.07 μm/s
Secondary useism: 0.49 μm/s
QUICK SUMMARY:
Looking at the high 2ndary microseism it seems to be from the storm off west coast with wave swells of 10m and a swell period of 7.6sec ( ~0.13Hz). Something weird is that the MY seismometer had a big sudden jump in motion at ~23:10 UTC.
FAMIS 27428, last checked in alog87417
All fans look to be well within acceptable noise range and behavior is largely unchanged compared to last week.
Another big EQ rolling through. This one is down near Antartica! Debated when to transition to "ASC Hi Gn", since R-wave was going to be 45-60min. But S&P waves triggered EQ Mode + saw a yellow Picket Fence---Clicked on ASC Hi Gn button, but during the transition H1 lost lock. This might have been too big for ASC Hi Gn regardless, but kinda wished I clicked it earlier.
Winds were peaking just under 40mph around the lockloss as well.
Will be hanging out here for a few hours.
Now we wait for R-wave which is probably due to arrive around 2135-ish utc.
We lost lock ~3 seconds after CHARD_Y filters bits are changed, there's also a big jump in ground motion at the same time, and it was gusting >30mph at the corner station.
TITLE: 10/09 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 155Mpc
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 5mph Gusts, 4mph 3min avg
Primary useism: 0.08 μm/s
Secondary useism: 0.18 μm/s
QUICK SUMMARY:
H1's been locked 16.5+hrs (even rode through an M6.0 Russia EQ an hr ago!).
OVERNIGHT: SQZ dropped H1 from Observing for 4min due to the PMC. NO Wake up Calls!
ALSO: Thurs Calibration from 830-noon (local time)...where Calibration will be deferred to later in the morning for Elenna task and/or Robert task starting things off.
Did the Dust Monitor Check and a new (to me atleast) problem would be for DR1 (Diode Room 1).
Did the Dust Monitor Check and a new (to me atleast) problem would be for DR2 (Diode Room 2).
Robert, Anamaria
Following up on tests done at L1, we wanted to do the same tests at H1 and compare. We see similar large shelves when we shake RX and RY at 0.2 Hz. This mechanism is not directly limiting DARM since we have to inject a lot to see it, but it allows us to estimate how much light is around the BS area available for scattering into DARM.
The stranger difference between the sites is that the ratio of the first shelf to the second shelf for H1 is much smaller, circa 10, so implies a second reflective path that's still fairly in line (eg like the R0 ESD reflections).
I drove 100 cts into the the corresponding ISO filter bank.
RX injection start: Oct 2 17:41:39 utc
duration: 8 min
RY injection start: Oct 2 17:58:20 utc
duration: 2 min (lost lock shortly after so weren't able to get more data)
dtts can be found in /ligo/home/anamaria.effler/ddt/ with suggestive names. I had also copied over the equivalent L1 dtts in the same directory.
Robert will folow up with some more tests.
Closes FAMIS#27426, last checked 87179
Corner Station Fans (attachment1)
- All fans are looking normal and within range.
Outbuilding Fans (attachment2)
- All fans are looking normal and are within range. You can see when EX fan 2 was turned off three days ago due to its noise increasing (issue fixed).
Closes FAMIS26687, last checked in alog86869
Nothing really of note, MR_FAN6_170_1 has some transient noise.
Closes FAMIS 26686. Last checked in alog 86718
Everything below threshold with the outage clearly visible as a blip (mostly in MY and MX fans).
Plots attached.
