Notice: I removed these 75Ohm video cables.

Thanks for the good preparation.  IFO pressure P1=20 Torr

 Jam nuts checked. Oplev servos turned off. Particle count checked. Vertex crane functionality checked.

ANTS ALERT please watch out for ants. We have them in the control room.

1. Jam nuts - checked that none of the nuts move by hand, which according to Steve, is sufficient. I recorded photos of all of them here.
2. Lab particle count - at the SP table, I measured 25,910 / cf @ 0.3 um and 1220 /cf  @ 0.5 um. Steve's guidance is that the latter number should be less than 10,000, so no issues there.
3. Valves - closed all the annuli off, and also closed VM1, VA6 and V1. The procedure calls for VM3 to be opened, presumably so that the RGA remains pumped, but I see no reason why we can't just leave that RGA volume valved off.
4. Started letting N2 into the main volume at ~3pm local time, by opening VV1. Attachment #1 shows the valve configuration adopted for this vent. Went up to 25 torr and then switched over to the "Ultra Zero" instrument grade air cylinders.
5. Aimed for 3-5 torr/min rate of pressure increase locally. The full vent trend can be seen in Attachment #2.
6. Stopped letting air into the main volume when P1a pressure was 700 torr, at which point I disconnected the cylinders from the main volume, and left VV1 open so that the IFO equilibriates to the lab air pressure. I used 4 full cylinders of the instrument grade air, which is par for the course. 
7. Since we anticipate opening the ETMY and output optics chambers, I also vented those annuli. The final state of the valves as I am leaving it for the night is shown in Attachment #3.
8. I re-aligned the IMC mirrors so that I could lock the IMC at low power once again. Indeed, IMC trans of ~1400 cts was realized (see Attachment #4), c.f. ~1500 earlier today, I thought this is fine and didn't optimize further. I think the policy is to not lock the IMC in air unless necessary, so I'm leaving the PSL shutter closed for the night.
9. The ITMs, ETMs and BS were re-aligned such that the Oplev spots are centered. I can see some higher order resonances of the green beams. The AS spot is fringing (the two ND=0.5 filters on the AS CCD camera were removed for better visibility). So this is fine as far as alignment is concerned.

We are now ready to take the doors off. I've already done the basic prep work (loosened bolts, cleaned chamber, carts for tools, fresh ameristat on portable HEPAs etc).

Summary

- The vacuum chambers have been vented.

- The north heavy door of the BS chamber has been opened by Genie (not by the crane).
It was replaced by the light door. The door is currently closed.

- The MC has been locked with 20mW incident and aligned. MC REFL was left unchanged but lock was able to be achieved.

- The optics before MCT CCD and MCT QPD have been adjusted for the low power operation.

Details

- The first HWP for the variable optical attanuator (HWP/PBS/HWP pair) was set to be 86deg from the maximum transmission at 126deg.
The incident power of 19mW has been measured.

- The PSL mechanical shutter has been manually opened. Two other beam blocks has been removed.

- I found the MC was totaly misaligned with no resonance.- I tried to align it based on the previous OSEM values but in vain.

• How to align the MC mirrors from the scratch

- MC1 has been aligned so as to maximize REFL PD and DC signal of WFS QPDs.

- MC3 has been aligned by looking at the scattered light on the MC2 frames. The spot is centered on the MC2 approximately.

- MC2 has been aligned so that any resonance is seen in MC_F.

• Modification of the MCT optics

- The ND filter before the MCT was removed.

- The Y1-45S mirror before the MCT CCD, which is also used to steer the beam to the MCT QPD path, was replaced to BS1-50-45P.
The reason I used 45P is to obtain higher reflectivity. Because S has higher reflectivity than P in the each layer, I expected to have higher reflectivity for S than 50%.

- The MC REFL path has not been untouched.

• Modification of the servo

- The lock was attempted after alignment of the mirrors.  Here how to lock the MC is described below.

1. Run script/MC/mcloopson

2. Open the MC Servo screen in MEDM

3. Change the input gain from 6dB to 22dB.
Change offset from 0.78 to -0.464 (such that the length output has no offset).
Change VCO Gain from 3dB to 21dB

Change MC Length path Gain from 0.3 to 1.6

[koji, gautam]

1. Glued broken off magnet - curing overnight with lamp to slightly elevate temp for curing.
2. Remvoed material from OMC chamber as per the plan. This is all sitting wrapped up in foil on a cart for tonight, we should figure out a better storage plan eventually.

The IMC isn't resonant for a TEM00 mode at the time of writing - we are waiting for the stack to relax, at which point if the IMC isn't resonant for a TEM00 mode, we will tweak the input pointing into the IMC (we want to use the suspended cavity as the reference, since it is presumably more reliable than the table from which we removed ~50 kgs of weight and shifted the balance.

[koji, gautam]

1. Tweaked last steering mirror before PSL beam is launched into vacuum to get the IMC resonant for the TEM00 mode. Less than 1/8 turn in each Pitch and Yaw was required, and we recovered MC2T ~ 1300 cts (c.f. the expected ~1500 cts when the cavity is well aligned, but we didn't touch the IMC mirrors).
2. ETMY magnet re-gluing
   • Regluing was successful. Pickle picker came off smoothly. 
   • We performed the razor blade test on all 6 magnets, the integrity of the joints seems uncompromised.
3. ETMY cleaning
   • Applied F.C. to HR face, HR edge (to remove some residual stains) and AR surface (taking care to go around the magnets).
   • A fresh bottle each of spectroscopic grade acetone and isopropanol was dispensed into clean beakers for the work.
   • Curiously, in the lighting conditions of the cleanroom, both HR and AR faces looked surprisingly clean, even when illuminated with the green flashlight.
   • However, when we took it to the east end and looked at it again with the green flashlight, just before putting it into the chamber, we saw all sorts of stains and markings on the HR side.
   • The central aperture looks fine - the contamination did not happen during the transport so we feel confident not to futz around more with this and since we cleaned it extensively in the cleanroom, we opted not to do another round of cleaning in the chamber.
4. ETMY re-suspension (on the existing wire loop)
   • The back OSEM-holding plates were removed for access reasons.
   • The optic was rested onto the EQ stops. 
   • Patient nudging of the wire around the optic allowed us to eventually get the wire into the V-grooves in the standoffs.
   • The wire was not damaged! (at least, to eye, free-swinging test is going on now, we will see what the eigenfrequencies and Qs are)...
   • We confirmed that the wire is seated in the v-groove, and took some close up photos.
5. ETMY pitch balancing
   • A HeNe was brought into the cleanroom and mounted at 5.5" beam height.
   • Level-ness of the beam (i.e. parallel to the optic table) was done coarsely with a spirit level placed on the HeNe holder, and more fine adjustment was done by checking the beam height at the launch point, and again ~2 meters away.
   • All EQ stops were backed off to ensure the optic was really "free-swinging" - no OSEMs either at this point, since all this was done in the cleanroom.
   • The return beam hit the HeNe's output aperture, so we were satisfied that the pitch balancing was good to ~1mrad.
6. ETMY transport back to EY
   • Since we want to maintain some tension in the wires, the bottom EQ stops were not raised as much as they were when the tower was transported from EY to the cleanroom.
   • As a result, we felt it'd be better for a human (Koji) to carry the cage (rather than cart it, the idea being that there would be fewer vertical impulses due to bumps on the ground etc).
   • The transport went smooth.
7. EY chamber work
   • Optic was placed back in its original position (marked by some L-clamps).
   • In preparation for alignment work, I undid all the CDS changes I made to facilitate the temporary 3-magnet actuation. This necessitated a reboot of c1auxey VME crate.
   • OSEMs were inserted - best effort to half light as usual, and we tried to replicate the rotation in the mounts as closely as possible to what was the case before (using a photo from the last vent as reference).
   • Coarse alignment was done by making the Oplev return beam hit the QPD.
   • Better alignment of the Y-arm cavity axis was done using the green beam. 
   • IMC was locked - the beam alignment target was used to ensure the IR beam was hitting ETMY at the correct height (by moving TT2), and then the ETMY angular alignment was improved to make the return beam go back roughly collinearly.
8. Y-arm POY locking
   • Satisfied with the alignment, we returned to the control room (light doors back on EY chamber) - cavity alignment was tweaked further to make the TRY resonances as high as possible.
   • I could lock the Y-arm length to the PSL frequency using POY as a sensor - TRY was ~0.04-0.05 (since IMCT is 1/10th its usual value, we expect it to be 0.1, so this is not bad).
9. OMC chamber work
   • Tied down the balance weights that were previously placed after the OMC and peripheral optics were removed.
   • Checked the table leveling.
   • Checked that the AS beam is reasonably well centerd on OM5 and OM6. Took some photos.
   • Checked that the IMC could be locked after this work - it could.

So all the primary vent objectives have been achieved 🙌 . The light doors are on the chamber right now. I'm measuring the free-swinging spectra of ETMY overnight. Barring any catastrophic failures and provided all required personnel are available, we will do the final pre-close-up checks, put the heavy doors back on, and pump down starting 10 am Monday, 9 Nov 2020. Some photos here.

Basic IFO alignment checks were done.

1. IMC could be locked - I tweaked the cavity alignment a little to maximize the MC transmission.
2. Y arm can be made resonant for a TEM00 mode of the main beam. I can't run ASS successfully in this low power config. I can see that the axis isn't great, the spot is visually off-center on ITMY, but we should have plenty of actuator range to correct for this with TT1/TT2.
3. X arm shows IR mode flashes in the TRX QPD. The green beam can be made resonant for a TEM00 mode, but that alignment doesn't yield the largest IR resonant peaks in TRX. I suspect it is due to the mis-alignment of the beam axis.
4. AS beam was aligned onto the CCD. I could see clean Michelson fringes by tweaking the BS alignment. On the AP table, I noticed that the beam on the first steering mirror after the AS beam exits the vacuum is a little high. We can easily resolve this by tweaking OM6 pitch a bit, but even if we don't I don't see any major issues as there is plenty of clearance w.r.t. the viewport when the beam exits the vacuum.
5. With the PRM aligned, I can see the REFL beam on the CCD, and it doesn't look clipped.
6. I didn't bother to align the green beams to the arm cavities or re-center the Oplevs - is this necessary? It is a step in the pre-close up checklist, so maybe we should do it... The green transmission does reach the PSL table...

Tomorrow, we should do some visual checks of the chambers / EQ stops on ETMY etc but I don't see any major problems at the moment...

> I didn't bother to align the green beams to the arm cavities or re-center the Oplevs - is this necessary? It is a step in the pre-close up checklist, so maybe we should do it... The green transmission does reach the PSL table...

I don't think so. The beam is reaching the PSL, so we have no motivation to change the green alignment. Regarding the oplev, the green refl should come back to the PDH PD and this gives us additional beam reference. As soon as we find the green resonance after the pumping, we can tweak the green axis so that the spots on the mirrors become reasonable (as well as the green trans CCD on the PSL table).

[Chub, Jordan, Anchal, Koji]

- Checked the main volume is isolated.
- TP1 and TP2 were made isolated from other volumes. Stopped TP1. Closed V4 to isolate TP1 from TP2.
- TP3 was made isolated. TP3 was stopped.
- We wanted to vent annuli, but it was not allowed as VA6 was open. We closed VA6 and vented the annuli with VAVEE.
- We wanted to vent the volume between VA6, V5, VM3, V7 together with TP1. So V7 was opened. This did not change the TP1 pressure (P2 = 1.7mmTorr) .
- We wanted to connect the TP1 volume with the main volume. But this was not allowed as TP1 was not rotating. We will vent TP1 through TP2 once the vent of the main volume is done.

- Satrted venting the main volume@Oct 18, 2021 9:45AM PDT

- We started from 10mTorr/min, and increased the vent speed to 200mTorr/min, 700mTorr/min, and now it is 1Torr/min @ 20Torr
- 280Torr @11:50AM
- 1atm  @~2PM

We wanted to vent TP1. We rerun the TP2 and tried to slowly introduce the air via TP2. But the interlock prevents the action.

Right now the magenta volume in the attachment is still ~1mTorr. Do we want to open the gate valves manually? Or stop the interlock process so that we can bypass it?

[Chub, Jordan, Yehonathan, Anchal, Koji]

North door of the BS chamber opened

[Lydia, Johannes]

Took photos to document the original OSEM orientation and wrote down the serial numbers for each position. We removed the OSEMs, moved the suspension to the accessible side of the table and took out the optic, which was brought to the clean room to have the magnets reglued. The ETMY chamber is now closed up with the OSEMs and clamps inside on the table, and should not need to be reopened until the magnets have been reattached. 

I have updated the vent prep checklist on the wiki. Gautam and I did the following things from it:

• Center all oplevs, transmon QPDs 
  • ETMX oplev has not been centered, since it's moving around so much, and we're going to immediately move the suspension anyways.
• Align the arm cavities for IR and align the green lasers to the arms. 
  • AUX X Green was aligned while the X arm was well aligned. Soon thereafter, ETMX wandered away, but the green will remain a good reference
• Update the SUS Dritmon values 
• Reconcile all SDF differences 

• Reduce input power to no more than 100mW by adjusting wave plate+PBS setup on the PSL table BEFORE the PMC. (Using the WP + PBS that already exist after the laser.) 

• Replace 10% BS before MC REFL PD with Y1 mirror and lock MC at low power.
  • I don't think we've vented since the most recent slew of changes to the IMC servo, so its not surprising that the current low power scripts don't work. I'm working on locking the IMC, but this does not prevent us from initiating the vent tomorrow.

The following bullets have not yet been executed:

• Close shutter of PSL-IR and green shutters at the ends 
• Make sure the jam nuts are protecting bellows 

• Check crane functionality & cleanliness 

• Turn off HV into vacuum: OMC is not wired this time 
• Particle count must be under 10,000 counts / cf min for 0.5 micron 
• Check all metal window covers are on. 
• Check 5 cylinders (24 cft size) of instrument grade air, called Alfa Gas 1 in stock.

Steve has ordered some teflon parts to take the place of the metal parts in his acetone-soaking jig. They should arrive tomorrow. 

So, we will be begin the venting process tomorrow. Doors to come off on Tuesday.

1. Two arms / BS / PRM / SRM were aligned. (Attachment 1)
2. IMC was aligned by WFS and the WFS offsets were offloaded.
3. Suspension Status Snapshot (Attachment 2)
4. Oplevs are aligned (Attachment 3)
5. Xarm green was aligned in the daytime. Xarm green refl DC (C1:ALS-X_REFL_DC_OUTPUT) was 620 (aligned) ~1300 (drifted). When unlocked, it was 3750.
6. Yarm green: I saw no flash. We don't have functional PZT alignment since the ASY M2 PZT got broken. I went to the Yend. Something funky is going on with the Yend green. I struggled to have any flash of the cavity. The apertures were not so precise. I finally got TEM00 locked, but the modematching seems exteremely low (like 1/1000?). Basically I saw no power reduction of the refl when the cavity is locked. So at least the cavity was locked but we might need to revisit when we open the chamber
   ==> Gautam thinks it was not like that. So he will check the green alignment tomorrow (Thu).
7. Item checking: I familialized myself with the yend crane operation. Today I learned that there is a power switch on the wall (Attachment 4). The yend has two heavy door storages (Attachments 4/5). The slings to lift the heavy door are in the crane cabinet along with the y arm (Attachment 6). I didn't yet try to find the "hammer" to hit the door if the o-ring stuck too strong, although that's optional.
8. We want to reduce the PSL power. But Gautam wants to use the arm locking with the nominal power, it will be done tomorrow by him.
    
9. The last thing is to check the green trans power. I noticed that the green trans beams are blocked by an HWP for the BHD LO path on the PSL table. (Attachment 7)
   The HWP was moved and the process was recorded in the movie (Attachment 8). The fiber output was monitored by the BHD DC (aka AS110 DC) with the AS path blocked. The fiber output of 22.6mV (offset -2.5mV) was improved tio 29.1mV after the HWP move and the alignment adjustment.
10. Now the green transmissions are visible by the green PDs. Attachment 9 shows the trans and ref of each green beams with and without locking to TEM00. The questionable green TRY was ~0.3. If we compare this with the histrical data (Attachment 10), it is about 1/4 of the value in the past. It's not too crazy but still quite low.

At this point, I'm leaving the lab. All the suspensions (incl SRM) are aligned. PSL/GRX/GRY shutters were left open.

1. Oplev HeNe at ETMY was replaced, see here for my earlier discussion on this.
   • I thought this is a good idea since we want the Oplev as a coarse reference and it'd not be ideal if this HeNe dies during the time the optic is out of the chamber.
   • New HeNe had 2.8mW of power output as measured with Ophir power meter. This is in line with what is expected from these Lumentum heads.
   • I labelled the head with the power output and today's date, re-aligned the Oplev reflection onto its QPD. 
   • After this work, the Y-arm could be locked without the huge angular fluctuations that was visible earlier, 👍 .
2. GTRY anomaly
   • I actually judged that there is no anomaly.
   • The GTRY CDS indicator is actually quite useless - the ADC saturates at ~3500 cts (and not 32768 as you would expect from a 16 bit ADC but that's the well-known whitening filter saturation problem). This should be fixed, but this is a task for later.
   • I measured with a DMM the voltage when the TEM00 is locked to the cavity and GTRY is 0.3 (the nominal value these days), the DC voltage was ~5.6 V. The prompt reflection from the ETM registers ~6.5 V DC. So the mode-matching isn't stellar, but this is again a known issue, and can be fixed later.
3. Other pre-vent checks
   • The Oplevs had drifted significantly, I re-centered ITMs, ETMs and BS after aligning the arm cavities and green beams in the POX/POY lock state. See Attachment #1.
   • I locked the PRMI on carrier and used this config to re-center the PRM Oplev, see Attachment #2.
   • No further action was taken regarding SRM oplev.
   • I checked the ALS noise, see Attachment #3. The X arm ALS has excess noise at ~100 Hz that certainly wasn't there previosuly - sigh. There is nothing I can find about any changes made at EX in the elog.
   • Updated the "DriftMon" values, though I guess we don't even really use this anymore these days?
   • Re-relieved the IMC WFS offsets.
   • Cut the input power to the IMC from 1.007W to 100.1 mW (both numbers measured with Ophir power meter).
   • Replaced the 10% beamsplitter in the MCREFL path on the AS table with a Y1 HR mirror. Note that there is no beam on the IMC WFS in this configuration.
   • Was able to lock the IMC on low power to a TEM00 mode - need to set up the low power autolocker. The IMC autolocker is now set to the low power settings, and I've tested it locks a couple of times. Attachment #5 shows the low power lock in StripTool.
   • Walked around and looked at all the bellows - the jam nuts are up against their stops, and I can't move them with my hands, so I think that's okay.

If everything else looks good, I'll start letting the dry N2 into the main volume after lunch.

BTW, nice video! @ Koji, How difficult was it to edit it into this form? 

I centered all the optical levers on ITMX, ITMY, ETMX, ETMY, and BS to a position where the single arm lock on both were best aligned. Unfortunately, we are seeing the TRX at 0.78 and TRY at 0.76 at the most aligned positions. It seems less power is getting out of PMC since last month. (Attachment 1).

Then, I tried to lock PRMI with carrier with no luck. But I was able to see flashing of up to 4000 counts in POP_DC. At this position, I centered the PRM optical lever too (Attachment 2).

I took over the vent prep: I'm going through the list in [ELOG 15649] and [ELOG 15651]. I will also look at [ELOG 15652] at the day of venting.

1. IFO alignment: Two arms are already locking. The dark port beam is well overlapped. We will move PRM/SRM etc. So we don't need to worry about them. [Attachment 1]
   scripts>z read C1:SUS-BS_PIT_BIAS C1:SUS-BS_YAW_BIAS
-304.7661529521767
-109.23924626857811
scripts>z read C1:SUS-ITMX_PIT_BIAS C1:SUS-ITMX_YAW_BIAS
15.534616817500943
-503.4536332290159
scripts>z read C1:SUS-ITMY_PIT_BIAS C1:SUS-ITMY_YAW_BIAS
653.0100945988496
-478.16260735781225
scripts>z read C1:SUS-ETMX_PIT_BIAS C1:SUS-ETMX_YAW_BIAS
-136.17863332517527
181.09285307121306
scripts>z read C1:SUS-ETMY_PIT_BIAS C1:SUS-ETMY_YAW_BIAS
-196.6200333695437
-85.40819256078339
    
2. IMC alignment: Locking nicely. I ran WFS relief to move the WFS output on to the alignment sliders. All the WFS feedback values are now <10. Here is the slider snapshots. [Attachment 2]
    
3. PMC alignmnet: The PMC looked like it was quite misaligned -> aligned. IMC/PMC locking snapshot [Attachment 3]
   Arm transmissions:
   scripts>z avg 10  C1:LSC-TRX_OUT C1:LSC-TRY_OUT
C1:LSC-TRX_OUT 0.9825591325759888
C1:LSC-TRY_OUT 0.9488834202289581
    
4. Suspension Status Snapshot [Attachment 4]
    
5. Anchal aligned the OPLEV beams [ELOG 16407]
   I also checked the 100 days trend of the OPLEV sum power. The trend of the max values look flat and fine. [Attachment 5] For this purpose, the PRM and SRM was aligned and the SRM oplev was also aligned. The SRM sum was 23580 when aligned and it was just fine (this is not so visible in the trend plot).
    
6. The X and Y green beams were aligned for the cavity TEM00s. Y end green PZT values were nulled. The transmission I could reach was as follows.
   >z read C1:ALS-TRX_OUTPUT C1:ALS-TRY_OUTPUT
0.42343354488901286
0.24739624058377277
   It seems that these GTRX and GTRY seemed to have crosstalk. When each green shutters were closed the transmissino and the dark offset were measured to be
   >z read C1:ALS-TRX_OUTPUT C1:ALS-TRY_OUTPUT
0.41822833190834546
0.025039383697636856
>z read C1:ALS-TRX_OUTPUT C1:ALS-TRY_OUTPUT
0.00021112720155274818
0.2249448773499293
   Note that Y green seemed to have significant (~0.1) of 1st order HOM. I don't know why I could not transfer this power into TEM00. I could not find any significant clipping of the TR beams on the PSL table PDs.
    
7. IMC Power reduction
   Now we have nice motorized HWP. sitemap -> PSL -> Power control
   == Initial condition == [Attachment 6]
   C1:IOO-HWP_POS 38.83
   Measured input power = 0.99W
   C1:IOO-MC_RFPD_DCMON = 5.38
   == Power reduction == [Attachment 7]
   - The motor was enabled upon rotation on the screen
   C1:IOO-HWP_POS 74.23
   Measured input power = 98mW
   C1:IOO-MC_RFPD_DCMON = 0.537
   - Then, the motor was disabled
    
8. Went to the detection table and swapped the 10% reflector with the 98% reflector stored on the same table. [Attachments 8/9]
   After the beam alignment the MC REFL PD received about the same amount of the light as before.
   C1:IOO-MC_RFPD_DCMON = 5.6
   There is no beam delivered to the WFS paths.
   CAUTION: IF THE POWER IS INCREASED TO THE NOMINAL WITH THIS CONFIGURATION, MC REFL PD WILL BE DESTROYED.
9. The IMC can already be locked with this configuration. But for the MC Autolocker, the MCTRANS threshold for the autolocker needs to be reduced as well.
   This was done by swapping a line in  /opt/rtcds/caltech/c1/scripts/MC/AutoLockMC.init
# BEFORE
/bin/csh ./AutoLockMC.csh >> $LOGFILE
#/bin/csh ./AutoLockMC_LowPower.csh >> $LOGFILE
--->
# AFTER
#/bin/csh ./AutoLockMC.csh >> $LOGFILE
/bin/csh ./AutoLockMC_LowPower.csh >> $LOGFILE
   Confirmed that the autolocker works a few times by toggling the PSL shutter. The PSL shutter was closed upon the completion of the test
    
10. Walked around the lab and checked all the bellows - the jam nuts are all tight, and I couldn't move them with my hands. So this is okay according to the ancient tale by Steve.

From the IFO point of view, all look good and we are ready for venting from Mon Oct 18 9AM

[chub, gautam]

• IFO pressure was ~2e-4 torr when we started, on account of the interlock code closing all valves because the N2 line pressure dropped below threshold (<65 psi)
• Chub fixed the problem on the regulator in the drill-press area where the N2 tanks are, the N2 line is now at ~75 psi so that we have the ability to actuate valves if we so desire
• We decided that there is no need to vent the pumpspool this time - avoiding an unnecessary turbo landing, so the pumpspool is completely valved off from the main volume and TPs 1-3 are left running
• Went through the pre-vent checklist:
  • Chub measured particle count, deemed it to be okay (I think we should re-locate the particle counter to near 1X8 because that is where the air enters the IFO anyways, and that way, we can hook it up to the serial device server and have a computerized record of this number as we had in the past, instead of writing it down in a notebook)
  • Checked that the PSL was manually blocked from entering the IFO
  • Walked through the lab, visually inspected Jam Nuts and window covers, all was deemed okay
• Moved 2 tanks of N2 into the lab on account of the rain
• Started the vent at ~930am PST
  • There were a couple of short bursty increases in the pressure as we figured out the right valve settings but on average, things are rising at approx the same rate as we had in vent 81...
  • There was a rattling noise coming from the drypump that is the forepump for TP2 (Agilent) - turned out to be the plastic shell/casing on the drypump, moreover, the TP2 diagnostics (temperature, current etc) are all normal.
  • The CC1 gauge (Hornet) is supposed to have an auto-shutoff of its High Voltage when the pressure exceeds 10 mTorr, but it was reporting pressures in the 1 mTorr range even when the adjacent Pirani was at 25 torr. To avoid risk of damage, we manually turned the HV off. There needs to be a python script that can be executed to transition control between the remote and local control modes for the hornet, we had to Power Cycle the gauge because it wouldn't give us local control over the HV.
  • Transitioned from N2 to dry air at P1a=25 torr. We had some trouble finding the correct regulator (left-handed thread) for the dry air cylinders, it was stored in a cabinet labelled green optics
  • Disconnected dry air from VV1 intake once P1b reached 700 torr, to let lab air flow into the IFO and avoid overpressuring.
  • VA* and VAV* valves were opened so as to vent the annuli as we anticipate multiple chamber openings for this vent.

As of 8pm local time, the IFO seems to have equilibriated to atmospheric pressure (I don't hear the hiss of in-rushing air near 1X8 and P1a reports 760 torr). The pumpspool looks healthy and there are no signs in the TP diagnostics channels that anything bad happened to the pumps. Chub is working on getting the N2 setup more robust, we plan to take the EY door off at 9am tomorrow morning with Bob's help.

* I took this opportunity to follow instructions on pg 29 of the manual and set the calibration for the SuperBee pirani gauge to 760 torr so that it is in better agreement with our existing P1a Pirani gauge. The correction was ~8% (820-->760).

Vent 80 is nearly complete; the instrument is almost to atmosphere.  All four ion pump gate valves have been disconnected, though the position sensors are still connected,and all annulus valves are open.  The controllers of TP1 and TP3 have been disconnected from AC power. VC1 and VC2 have been disconnected and must remained closed. Currently, the RGA is being vented through the needle valve and the RGA had been shut off at the beginning of the vent preparations.  VM1 and VM3 could not be actuated.  The condition status is still listed as Unidentified because of the disconnected valves. 

Gautam, Aaron, Chub and Steve,

The vent 81 is completed.

4 ion pumps and cryo pump are at ~ 1-4 Torr (estimated as we have no gauges there), all other parts of the vacuum envelope are at atm. P2 & P3 gauges are out of order.

V1 and VM1 are in a locked state. We suspect this is because of some interlock logic.

TP1 and TP3 controllers are turned off.

Valve conditions as  shown: ready to be opened or closed or moved or rewired. To re-iterate: VC1, VC2, and the Ion Pump valves shouldn't be re-connected during the vac upgrade.

Thanks for all of your help.

Gautam, Aaron, Chub & Steve,

ETMY heavy door replaced by light one.

We did the following:  measured 950 particles/cf min of 0.5 micron at SP table, wiped crane and it's cable, wiped chamber,

                                placed heavy door on clean merostate covered stand, dry wiped o-rings and isopropanol wiped Aluminum light cover

[Gautam, Johannes, Koji, Annalisa]

Tonight we increased the power of the PSL laser and we achieved the lock of both arms with high power.

The AUX beam alignment to the Y arm was recovered and the PLL restored (using the Marconi as LO).

We made a quick measurement of the phase noise and the results will be posted tomorrow.

The beam on the PSL has been blocked, as well as the AUX beam on the AS table. The Marconi has been switched off.

gautam:

1. Before turning up PSL power, I placed a block in front of MC refl to avoid any PD burning. Replaced HR Y1 2" optic with the usual 10% reflective BS to direct MC REFL to the locking PD.
2. Waveplate was rotated back to 180 deg (original position before the vent). After optimizing PMC transmission, I measured 1.05 W going into the IMC (pre-vent value was 1.07 W, prolly within power meter absolute accuracy).
3. IMC autolocker restored to usual high power version on megatron.
4. There seems to be some kind of vacuum interlock in effect that prevents me from opening the PSL shutter via EPICS - I had to toggle the position on the shutter controller under the table. After tonight's work, I returned the controller to the NC state, to avoid any further interference with this interlock code that may prevent pumping in the AM.
5. PLL gain was re-adjusted to achieve maximum stability (judged by eye) of the beat-note in lock triggered on the Marconi LO signal. Alignment onto the NF beatPD was also tweaked to squeeze out as much beat as possible.
6. The main objective tonight was to send AUX beam in, recover transmission beat, scan the AUX frequency, and resolve some peaks (MAX HOLD scanning technique, magnitude only for now, no phase info). Thanks to JE's expert fiber alignment and beatnote maximization, we achieved this . Annalisa will post a plot tmr. 
7. For unknown reasons, the Y arm ASS does not maximize TRY. So we are in the unfortunate situation of neither arm having a working ASS servo. To be worked on later.

Is the reflector too close to the beam and causing clipping?

Steve and Aaron,

6 hrs vent is reaching equlibrium to room air. It took 3 and a half instrument grade air cilynders [ AI UZ300 as labelled ] at 10 psi pressure. Average vent speed ~ 2 Torr/min

Valve configuration: IFO at atm and RGA is pumped through VM2 by TP1 maglev.

[aaron, steve]

Steve gave me a venting tutorial. I'll record this in probably a bit more detail than is strictly necessary, so I can keep track of some of the minor details for future reference.

Here is Steve's checklist:

• Check that all jam nuts are tightened
• all viewports are closed
• op levs are off
• take a picture of the MEDM screens
• Check particle counts
• Check that the cranes work & wiped
• Check that HV is off

Gautam already did the pre-vent checks, and Steve took a screenshot of the IFO alignment, IMC alignment, master op lev screen, suspension condition, and shutter status to get a reference point. We later added the TT_CONTROL screen. Steve turned off all op levs.

We then went inside to do the mechanical checks

• N2 cylinders in the 40m antechamber are all full enough (have ~700psi/day of nitrogen)
• We manually record the particle count
  • this should be <10,000 on the 0.5um particles to be low enough to vent, otherwise we will contaminate the system
  • note: need to multiply the reading on the particle counter by 10 to get the true count
  • the temperature inside the PSL enclosure should be 23-24C +/- 3 degrees
  • We recorded the particle counts at ~830 and ~930, and the 0.5um count was up to ~3000
• We put a beam stop in front of the laser at the PSL table
• Checked that all HV supplies are either off or supplying something in air
  • we noticed four HV supplies on 1X1 that were on. Two were accounted for on the PSL table (FSS), and the other two were for C1IOO_ASC but ran along the upper cable rack. We got ahold of Gautam (sorry!) and he told us these go to the TT driver on OMC_SOUTH, where we verified the HV cables are disconnected. We took this to mean these HV supplies are not powering anything, and proceeded without turning these HV off.
  • There are HV supplies which were all either off or supplying something in-air at: 1Y4, 1Y2, OMC N rack, 1X9 (green steering HV)
• Checked that the crane works--both move up and down
  • vertex crane switch is on the wall at the inner corner of the IFO
  • y arm crane switch is on the N wall at the Y end
  • turn off the cranes at the control strip after verifying they work
• While walking around checking HV, we checked that the jam nuts and viewports are all closed
  • we replaced one viewport at the x arm that was open for a camera

After completing these checks, we grabbed a nitrogen cylinder and hooked it up to the VV1 filter. Steve gave me a rundown of how the vacuum system works. For my own memory, the oil pumps which provide the first level of roughing backstream below 500mtorr, so we typically turn on the turbo pumps (TP) below that level... just in case there is a calibrated leak to keep the pressure above 350mtorr at the oil pumps. TP2 has broken, so during this vent we'll install a manual valve so we can narrow the aperture that TP1 sees at V1 so we can hand off to the turbo at 500mtorr without overwhelming it. When the turbos have the pressure low enough, we open the mag lev pump. Close V1 if things screw up to protect the IFO. This 6" id manual gatevalve will allow us throttle the load on the small turbo while the maglev is taking over the pumping  The missmatch in pumping speed is 390/70 l/s [ maglev/varian D70 ]  We need to close down the conductive intake of the TP1 with manual gate valve so the 6x smaller turbo does not get overloaded...

We checked CC1, which read 7.2utorr.

Open the medm c0/ce/VacControl_BAK.adl to control the valves.

Steve tells me we are starting from vacuum normal state, but that some things are broken so it doesn't exactly match the state as described. In particular, VA6 is 'moving' because it has been disconnected and permanently closed to avoid pumping on the annulus. During this v ent, we will also keep pumping on the RGA since it is a short vent; steve logged the RGA yesterday.

We began the vent by following the vacuum normal to chamber open procedure.

1. VM1 closed
2. We didn't open VM3, because we want to keep the RGA on
3. Closed V1
4. Connect the N2 to the VV1 filter
   1. first puged the line with nitrogen
   2. We confirmed visually that V1 is closed
5. We opened VM2 to pump on the RGA with the mag lev pump.
   1. This is a nonstandard step because we are keeping the RGA pumped down.
   2. The current on TP3 is ~0.19A, which is a normal, low load on the pump
6. VV1 opened to begin the vent at ~10:30am
   1. use crescent wrench to open, torque wrench wheel to close
   2. Keep the pressure regulator below 10 psi for the vent. We started the vent with about 2psi, then increased to 8psi after confirming that the SUS sensors looked OK.
7. We checked the pressure plot and ITMX/ETMX motion to make sure we weren't venting too quickly or kicking the optics
   1. Should look at eg C1:SUS-ITMX_SENSOR_LL, as well as C1:Vac-P1_pressure
8. Once the pressure reaches 25torr, we switched over to dry air
   1. wipe off the outside dolly wheels with a wet rag, and exit through the x-arm door to get the air. Sweep off the area outside the door, and wipe off new air containers with the rag.
   2. Bring the cylinder inside, get the regulator ready/purged, and swap relatively quickly.
   3. We increased the vent speed to 10psi. 
   4. Steve says the vents typically take 4 of 300 cf cylinders from Airgas "Ultra Zero" AI  UZ300 that contains 0.1 PPM of THC

Everything looks good, so I'm monitoring the vent and swapping out cylinders.

At 12:08pm, the pressure was at 257 torr and I swapped out in a new cylinder.

Steve: Do not overpressurize the vacuum envelope! Stop around 720 Torr and let lab air do the rest. Our bellows are thin walled for seismic isolation.

[Deeksha, Cici]

We attempted to use vectfit to fit our earlier transfer function data, and were generally unsuccessful (see vectfit_firstattempt.png), but are much closer to understanding vectfit than before. Couple of problems to address - finding the right set of initial poles to start with has been very hard, and also however vectfit is plotting the phase data is unwrapping it, which makes it generally unreadable. Still working on how to mess with the vectfit automatically-generated plots. In general, our data is very messy (this is old data of the transfer function from last week), so we took more data today to see if our coherence was the problem (see TFSR785_28-06-2022_161937.pdf). As is visible from the graph, our coherence is terrible, and above 1kHz is almost entirely below 0.5 (or 0.2) on both channels. Figuring out why this is and fixing it is our first priority.

In the process of taking new data, we also found out that the optical table enclosure at the end of the X-arm does a decent job of sound isolation (see enclosure_open.mp4 and enclosure_closed.mp4). The clicking from the shutter is visible on a spectrogram at high frequencies when the enclosure is open, but not when it is closed. We also discovered that the script to toggle the shutter can run indefinitely, which can break the shutter, so we need to fix that problem!

Trying to vectfit to the data taken from the DFD previously but failing horribly. I will update this post as soon as I get anything semi-decent. For now here is this fit.

I think the fit fails as the measurement quality is not good enough.

The 2W NPRO from Valera arrived today and I haf hidden it somewere in the 40m lab!

Rana was so kind to make this entry for me

I wanted to check how the refl signals looked like.
I decided to measure the demod phase where PRCL and MICH appear, one by one.

The method I used is to actuate PRCL or MICH at a fixed frequency and rotate the demod phase such that
the signal at the actuating frequency disappears.

For the PRCL actuation, PRM was actuated by the lock-in oscillator with the amplitude of 100cnt.
For MICH, the ITMX and ITMY was actuate at the amplitude of 1000cnt and 1015cnt respectively.

The script I used was something like this

ezcaread C1:LSC-REFL11_PHASE_R
ezcaservo -r C1:CAL-SENSMAT_CARM_REFL11_Q_I_OUTPUT C1:LSC-REFL11_PHASE_R -g 100 -t 60
ezcaread C1:LSC-REFL11_PHASE_R

"11" should be changed according to the PD you want to test.
"Q" should be changed to "I" depending on form which quadrature you want to eliminate the signal

The option "-g" specifies the servo gain. This specifies which slope (up or down) of the sinusoidal curve the signal is locked.
Therefore, it is important to flip the signal angle 180degree if a negative gain is used.

Note: Original phase settings before touching them

REFL11  - 19.2
REFL33   135.4
REFL55    48.0
RELF165 -118.5

Here in the measurement PRMI was locked with AS55Q (MICH) and REFL55I (PRCL)


Without no serious reason I injected a peak at 503.1Hz. This peak is not notched out by the servo. There may have been
some residual effect of the feedback loops.

PRCL: By elliminating the peak from the Q quadrature, we optimize the I phase for PRCL.

REFL11,   minimize PRCL in "Q", gain, -1, -19.3659 deg
REFL33,   minimize PRCL in "Q", gain, -1, 132.813 deg
REFL55,   minimize PRCL in "Q", gain, -1, 20.9747 deg
REFL165, minimize PRCL in "Q", gain, -1, -119.004 deg

MICH: By elliminating the peak from the I quadrature, we optimize the Q phase for MICH.
If PRCL and MICH appears at the same phase, the resulting angles shows an identical number.

REFL11,   minimize PRCL in "I", gain, -1, -28.4526 deg
REFL33,   minimize PRCL in "I", gain, -1, 65.9148 deg
REFL55,   minimize PRCL in "I", gain, -1, 12.4051 deg
REFL165, minimize PRCL in "I", gain, -0.1, -143.75 deg

Then, the signal frequency was changed to 675Hz where the notch filters in the servo is active.

PRCL: By elliminating the peak from the Q quadrature, we optimize the I phase for PRCL.

REFL11,   minimize PRCL in "Q", gain, 1, -19.5224 deg
REFL33,   minimize PRCL in "Q", gain, -1, 135.868 deg
REFL55,   minimize PRCL in "Q", gain, 1, 48.5716 deg
REFL165, minimize PRCL in "Q", gain, 1, -122.398 deg

MICH: By elliminating the peak from the I quadrature, we optimize the Q phase for MICH.
If PRCL and MICH appears at the same phase, the resulting angles shows an identical number.

REFL11,   minimize PRCL in "I", gain, -10, -73.7153 deg
REFL33,   minimize PRCL in "I", gain, -10, 135.5 deg
REFL55,   minimize PRCL in "I", gain, 10, -2.55868 deg
REFL165, minimize PRCL in "I", gain, -5, -156.135 deg

This is just a test of the REFL channels for the arms signals. ETMX or ETMY were actuated.

YARM

REFL11, minimize ETMY in "Q", gain 100 => C1:LSC-REFL11_PHASE_R = 145.694
REFL55, minimize ETMY in "Q", gain 100 => C1:LSC-REFL11_PHASE_R = -60.1512

XARM

REFL11, minimize ETMX in "Q", gain 100 => C1:LSC-REFL11_PHASE_R = 142.365
REFL55, minimize ETMX in "Q", gain 100 => C1:LSC-REFL55_PHASE_R = -68.6521

The StripTool plot attached below shows various arm signals measured with the Y arm cavity swept using ALS.

Yellow: TRY

Blue: ALS additive OFFSET to the error signal

Red: Raw PDH error signal (POY11I)

Purple: Linearized PDH error (POY11/TRY)

Green: 1/Sqrt(TRY)-5 (No normalization)

Inverse Sqrt of the TRY had been implemented when this LSC controller was first coded.
It is confirmed that the calculation is working correctly.

GC650

Mean
Amplitude  X center       Y center       X waist  Y waist  Background offset from zero
           position (mm)  position (mm)  (mm)     (mm)
0.3743     1.7378         2.6220         0.7901   0.8650  0.0047

Standard Deviation
Amplitude  X center       Y center       X waist  Y waist  Background offset from zero
           position (mm)  position (mm)  (mm)     (mm)
0.0024     0.0006         0.0005         0.0005   0.0003  0.00001

Std/Mean x100 (percent)
Amplitude  X center       Y center       X waist  Y waist  Background offset from zero
           position (mm)  position (mm)  (mm)     (mm)
0.6%       0.03%          0.02%          0.06%    0.04%    0.29%


GC750

Mean
Amplitude  X center       Y center       X waist  Y waist  Background offset from zero
           position (mm)  position (mm)  (mm)     (mm)
0.2024     2.5967         1.4458         0.8245   0.9194  0.0418

Standard Deviation
Amplitude  X center       Y center       X waist  Y waist  Background offset from zero
           position (mm)  position (mm)  (mm)     (mm)
0.0011     0.0005         0.0005         0.0003   0.0005  0.00003

Std/Mean x100 (percent)
Amplitude  X center       Y center       X waist  Y waist  Background offset from zero
           position (mm)  position (mm)  (mm)     (mm)
0.6%       0.02%          0.04%          0.04%    0.05%    0.07%

For quite a while (no one knows how long), we've seen fluctuations in the 10-30 Hz seismic motion. This shows up as the purple trace on the seismic BLRMS on the wall projector.

The second plot shows that this is not only a periodic increase in the usual 29.5 Hz HVAC peak, but also an anomolous 32.2 Hz peak. Probably some malfunctioning machinery - maybe in the 40m or maybe on the roof.

The vac system is going down now for planned repairs [ELOG 15499]. It will likely take most of the day. Will advise when it's back up.

Vacuum work is completed. The TP2 and TP3 interlocks have been overhauled as proposed in ELOG 15499 and seem to be performing reliably. We're now back in the nominal system state, with TP2 again backing for TP1 and TP3 pumping the annuli. I'll post the full implementation details in the morning.

I did not get to setting up the new UPS units. That will have to be scheduled for another day.

Vacuum related work at atmosphere:

Atm1,  Check all chamber dog clamps tightness with torque wrench,

Atm2,  Replace old, black molibdenum disulfite bolts -nut with new silicon bronze nuts and clean SS bolts.

Atm3,  Replace CC1 cold cathode gauges: horizontal and vertical.

Attachment 1:
We are pumping the main volume with TP2. Once P1a reached the pressure ~2.2mtorr, we could open the PSL shutter. The TP2 voltage went up once but came down to ~20V. It's close to nominal now.
We wondered if we should use TP3 or not. I checked the vacuum pressure trends and found that the annulus pressures were going up. So we decided to open the annulus valves.

Attachment 2:
The current vacuum status is as shown in the MEDM screenshot.

There is no trend data of the valve status (sad)

To carry out the next steps of the vac refurbishment plan [ELOG 15499], I've ordered parts necessary for interfacing the UPS units and the analog TP2/3 controller outputs with c1vac. The purchase list is appended to the main BHD list and is located here. Some parts we already had in the boxes of Acromag materials. Jordan is gathering what we do already have and staging it on the vacuum controls console table - please don't move them or put them away.

The email address in the N2 checking script wasn't right - I now updated it to email the 40m list if the sum of reserve tank pressures fall below 800 PSI. The checker itself is only run every 3 hours (via cron on c1vac).

I reset the remote of this git repo to the 40m version instead of Jon's personal one, to ensure consistency between what's on the vacuum machine and in the git repo. There is now a N2 checker python mailer that will email the 40m list if all the tank pressures are below 600 PSI (>12 hours left for someone to react before the main N2 line pressure drops and the interlocks kick in). For now, the script just runs as a cron job every 3 hours, but perhaps we should integrate it with the interlock process?

This year we've struggled with vacuum controls unreliability (e.g., spurious interlock triggers) caused by decaying hardware. Here are details of the vacuum refurbishment plan I described on the 40m call this week.

☑ Refurbish TP2 and TP3 dry pumps. Completed [ELOG 15417].

☑ Automated notifications of interlock-trigger events. Email to 40m list and a new interlock flag channel. Completed [ELOG 15424].

☐ Replace failing UPS.

• Two new Tripp Lite units on order, 110V and 230V [ELOG 15465].
• Jordan will install them in the vacuum rack once received.
• Once installed, Jon will come test the new units, set up communications, and integrate them into the interlock system following this plan [ELOG 15446].
• Jon will move the pumps and other equipment to the new UPS units only after completing the above step.

☐ Remove interlock dependencies on TP2/TP3 serial readbacks. Due to persistent glitching [ELOG 15140, ELOG 15392].

Unlike TP2 and TP3, the TP1 readbacks are real analog signals routed to Acromags. As these have caused us no issues at all, the plan is to eliminate dependence on the TP2/3 digital readbacks in favor of the analog controller outputs. All the digital readback channels will continue to exist, but the interlock system will no longer depend on them. This will require adding 2 new sinking BI channels each for TP2 and TP3 (for a total of 4 new channels). We have 8 open Acromag XT1111 channels in the c1vac system [ELOG 14493], so the new channels can be accommodated. The below table summarizes the proposed changes.

We updated the vacuum control and monitor screens  (C0VAC_MONITOR.adl and C0VAC_CONTROL.adl).  We also updated the /cvs/cds/caltech/target/c1vac1/Vac.db file.

1) We changed the C1:Vac-TP1_lev channel to C1:Vac-TP1_ala channel, since it now is an alarm readback on the new turbo pump rather than an indication of levitation.  The logic on printing the "X" was changed from X is printed on a 1 = ok status) to X is printed on a 0 = problem status.  All references within the Vac.db file to C1:Vac-TP1_lev were changed.  The medm screens also now are labeled Alarm, instead of Levitating.

2) We changed the text displayed by the CP1 channel (C1:Vac-CP1_mon in Vac.db) from "On" and "Off" to "Cold - On" and "Warm - OFF".

3) We restarted the c1vac1 front end as well as the framebuilder after these changes.

Koji and Steve succeded rebooting C1vac1, C1vac2 and pressure reading is working now

More tomorrow .........

The serial connections to the vacuum gauges were recovered by rebooting c1vac1 and c1vac2.

Steve claimed that the vacuum screen had showed "NO COMM" at the vacuum pressure values.
The epics connection to c1vac was fine. We could logged in to c1vac1 with telnet too although c1vac2 had no response.

After some inspection, we decided to reboot the slow machines. Steve manually XXXed YYY valves (to be described)
to prepare for any possible unwanted switching. Initially Koji thought only c1vac2 can be rebooted. But it was wrong.
If the reset button is pushed, all of the modules on the same crate is reset. So everything was reset. After ~3min we still
don't have the connection to c1vac1 restored. We decided to another reboot. This time I pushed c1vac1 reset button.
After waiting about two minutes, the ADCs started to show green lights and the switch box started scanning.
We recovered the telnet connection to c1vac1 and epics functions. c1vac2 is still note responding to telnet, and
the values associated with c1vac2 are still blank.

Steve restored the valves and everything was back to normal.

Koji and Steve,

One computer expert and one vacuum expert required.

Atm 1,  problem condition: gauges are not reading for a week, error message "NO COMM" and all computer LEDs are green

Atm 2, prepare to safe reboot:

            a, close V1, disconnect it's power cable and turn off Maglev, wait till rotation stops

            b, close PSL shutter ( take adrenaline if needed )

            c, close V4, V5, VA6 valves and disconnect their cables. "Moving" error message indicating this condition.

               V1 is not showing "Moving" because its power cable disconnected only! It will show it if its position indicator cable is disconnected too. There is no need for that.

               These valves closed and disabled will not allow accidental venting of main volume.

            d, push reset, reseting c1vac2 will reset c1vac1 also, wait ~ 6 minutes

"Vacuum Normal" valve configuration was restored after succesful reboot as follows:

             a, reconnect cable and open V4 and V5 at P2 & P3 <1e-1 Torr

             b, observe that P2  < 1e-3 Torr and retsart Maglev

             c, wait till Maglev reaches full speed of 560 Hz and reconnect-open V1

             d, reconnect-open VA6 at P3 <1e-3 Torr

NOTE: VM1 valve was locked in open position and it was not responding before and after reboot

          Error message on Atm2 is indicating this locked condition: "opening VM1 will vent IFO"

          This is a fauls message. The valve is frozen in open position. We need a softwear expert help.

For some reason the workstation at the vac rack was off and unplugged. Nicole and I plugged its power back in to the EX rack.

I turned it on and it booted up fine; its not dead. To get it on to the network I just made the conversion from 131.215 to 192.168 that Joe had done on all the other computers several months ago.

Now it is showing the Vacuum overview screen correctly again and so Steve no longer has to monopolize one of the Martian laptops over there.