Really!? I didn't reboot the machines between "sudo date" and "rtcds start c1x0*". I tried rtcds. If it didn't work, it used date. Then tried rtcds. (repeat) The time was not synched at all wrt the time zones and also the time. There were 1~3 sec offset besides the TZ problem.
Testing the satellite amp i.e. PD driver
- To test the noise of the PD transimpedance amps: Leave the PD input open (do not short the terminal goes to the PD)
- To test the current noise of the LED drivers: Short the output with an appropriate Rs to have the nominal current.
- To test the overall noise level together with the LED/PD pair: Connect the dummy OSEM module.
Testing the coil drivers
- Short the output with an appropriate Rs.
The curie temp of SmCo seems about x2 (in K) of the one for NdFeB. i.e. 600K vs 1000K. So I believe 177degC = 450K is not an issue. Just make sure the curie temp, referring the specific property for the magnets from this company. (You already know the company from the procurement doc). It'd be great if you upload the doc on the 40m wiki.
Note from today's meeting:
1. Can we adjust the thickness of the cylindrical hole for the mirror to move the COM in the plane of the wires. (We should be able to do that)
2. Please check how much we can displace the COM by the bottom dumbbell.
For your planning:
Yeah, it's really inconsistent. You had 35mA LED drive and the current noise of the noisy channel was 5e-7 A/rtHz at 1Hz. The RIN is 1.4e-5 /rtHz. The approx. received photocurrent is 30uA as we discussed today and this should make the noise around 4e-10 A/rtHz at 1Hz. However, the readout noise level is better than this level. (well below 1e-10 A/rtHz)
BTW, the IMC seemed continuously locked for 5 hours. Good sign.
Todd provided us a bunch of electronics. I went to Downs to pick them up this afternoon and checked the contents in the box. Basically, the boxes are pretty comprehensive to produce the following chassis
Some panels are missing (we cannibalized them for the WFS electronics). Otherwise, it seems that we will be able to assemble these chassis listed.
They have placed inside the lab as seen in the attached photo.
HAM-A COIL DRIVER (Req Qty 28+8)
- 8 Chassis
- 8 Front Panels
- 8 Rear Panels
- 8 HAM-A Driver PCBs
- 8 D1000217 DC Power board
- 8 D1000217 DC Power board
16bit AA (Req Qty 7)
- 7 CHASSIS
- 6 7 Front Panels (1 missing -> [Ed 2/22/2021] Asked Chub to order -> Received on 3/5/2021)
- 7 Rear Panels
- 28 AA/AI board S2001472-486, 499-511
- 7 D070100 ADC AA I/F
- 7 D1000217 DC Power board
18bit AI (Req Qty 4)
- 4 CHASSIS
- 4 Front Panels
- 4 Rear Panels
- 8 AA/AI board S2001463-67, 90-92
- 4 D1000551 18bit DAC AI I/F
- 4 D1000217 DC Power board
- bunch of excess components
16bit AI (Req Qty 5)
- 5 CHASSIS
- 4 5 Front Panels (D1101522) (1 missing -> [Ed 2/22/2021] Asked Chub to order -> Received on 3/5/2021)
- 3 5 Rear Panels (D0902784) (2 missing -> [Ed 2/22/2021] Asked Chub to order -> Received on 3/5/2021)
- 10 AA/AI board S2001468-71, 93-98
- 5 D1000217 DC Power board
- 5 D070101 DAC AI I/F
Internal Wiring Kit
Asked Chub to order:
- Qty 12 1U Hamilton Chassis
- Qty 5 x Front/Rear Panels/Internal PCBs for D1002593 BIO I/F (The parts and connectors to be ordered separately)
-> Front/Rear Panels received (3/5/2021)
-> PCBs (unpopulated) received (3/5/2021)
-> Components ordered by KA (3/7/2021)
We want to move the CoM with the adjustment range so that the residual deviation is adjusted by the bottom dumbbell. 0.0003" is well within the range and good enough.
Jordan's screenshot actually shows that the vertical distance (Y) is 0.0000". We want to have the vertical distance of CoM from the wire clamping point to be 0.9mm in the nominal SOS design (this might need to be adjusted to have a similar pitch resonant freq for the different inertia of moment). Let's say it is ~mm ish.
The full range of the bottom dumbbell adjustment gives us the CoM adjustment range of +/-0.002” = +/-50um. This corresponds to an alignment range of +/-50mrad. And we want to set it within +/-500urad.
So we need to adjust the dumbbell position with the precision of 1/100 of the full range (precision of 0.5um).
The groove does not extend to the top of the clamp. The groove shallower than the wire diameter cause the hysteresis of the alignment. Also, the material of the pieces should be stainless steel. Al clamp is softer than the wire and will cause the groove to be dug on the material, causing increased bending friction and hysteresis again.
Saying, all of our suspended masses with Al stand-offs are suffering this issue to some extent. That was the reason to buy the ruby standoffs.
We received currently available sets. We are supposed to receive more coil drivers and sat amps, etc. But they are not ready yet.
I can't obtain a consistent view between the existing drawings/photographs and your pin assignment. Please review the pin assignment again to check if yours is correct.
Looking from the back side and the wires are going down, the left bottom pin is "Coil Start" and the upper right adjacent pin is "Coil End". (See attachment)
So in your picture 1 should be the coil start and 4 should be the coil end, but they are not according to your table.
This is my current understanding of the in-vacuum wiring:
2. From the above facts, the in-vacuum cable is
Accuglass has the DSUB25 F-F cable off-the-shelf. However, this cable mirrors the pinout (see the datasheet on the pdf in the following link)
3. The options are
- ask Accuglass to make a twisted version so that the pinout is not mirrored.
- combine Accuglass female-male cable (https://www.accuglassproducts.com/connector-connector-extension-cable-25-way-femalemale) and a gender changer (https://www.accuglassproducts.com/gender-adapter-25d)
4. The length will be routed from the feedthrough to the table via the stacks like a snake to be soft. So, it will require some extra length.
5. Also, the Accuglass cables don't have a flap and holes to fix the connector to a cable post (tower). If we use a conventional 40m-style DSUB25 post (D010194), it will be compatible with their cables. But this will not let us use a DSUB25 male connector to mate. In the future, the suspension will be upgraded and we will need an updated cable post that somehow holds the connectors without fastening the screws...
This is very disappointing. Even with KEPCO linear supply with the improved HV driver circuit, the noise level is significantly higher than the 20kOhm R thermal noise.
What is special with the HP supplies? Can you replace KEPCOs with the HP supply, one by one to specify which one is making the noise bad?
EQs seen on Summary pages
A new hybrid splitter (DQS-10-100) was installed. As the amplification of the final stage is sufficient for the input level of 3dBm, I have bypassed the input amplification (Attachment 1). One of the mixer was desoldered to check the power level. With a 1dB ATTN, the output of the last ERA-5 was +17.8dBm (Attachment 2). (The mixer was resoldered.)
With LO3dBm. RF0dBm, and delta_f = 30Hz, the output Vpp of 340mV and the phase difference is 88.93deg. (Attachment 3/4, the traces were averaged)
I made the inspection of the new custom DSub cables (came from Texas).
The shelled version gives us some chance to inspect/modify the internal connections. (good)
The wires are well insulated. The conductors are wrapped with the foils and then everything is in the braid tube shield. The braid is soldered on one of the connectors. (Attachment 3/4 shows the soldering of the conductor by intentionally removing one of the insulations).
It wasn't clear that if the conductors are twisted or not (probably not).
Received additional front/rear panels. Updated the original entry and Wiki [Link]
Missed to note: The IF test was done at TP7 and TP6 using pomona clips i.e. brefore the preamp.
The parts will be ordered by Koji The components for the additional BIO I/F have been ordered.
I believe the aLIGO style invac dsub cables and the conventional 40m ones are incompatible.
While the aLIGO spec is that Pin1 (in-vac) is connected to the shield, Pin13 (in-vac) is the one for the conventional cable. I still have to check if Pin13 is really connected to the shield, but we had trouble before for the IO TTs https://nodus.ligo.caltech.edu:8081/40m/7864.
(At least one of the existing end cables did not show this Pin13-chamber connection. However, the cables OMC/IMC chambers indicated this feature. So the cables are already inhomogenious.)
- Which way do we want to go? Our electronics are updated with aLIGO spec (New Sat amp, OMC electronics, etc), so I think we should start making the shift to the aLIGO spec.
- Attachment Top: The new coil drivers can be used together with the old cables using a custom DB25 cable (in-air).
- Attachment Mid: The combination of the conventional OSEM wiring and the aLIGO in-vac cable cause the conflict. The pin1 which is connected to the shield is used for the PD bias.
- Attachment Bottom: This can be solved by shifting the OSEMs by one pin.
o The aLIGO cables have 12 twisted pair wires, but paired signals do not share a twisted pair.
--- No. This can't be solved by rotating the connectors.
o This modification should be done only for the new suspension.
--- In principle, we can apply this change to any SOSs. However, this action involves the vent. We probably want to install the new electronics for the existing suspensions before the vent.
o ^- This means that we have to have two types of custom DB25 in-air cables.
--- Each cable should handle "Shield wire" from the sat amp correctly.
Active TT Pin Issue
and the thread
Active TT Pin Swapping (December 21, 2012)
TT Wiring Diagram (Wiki)
How were the statistics of them? i.e. # of Good OSEMs, # of OK OSEMs, etc...
I just saw the PRM watchdog tripped at ~15:20 local (23:20UTC). I restored the PRM but I saw only the side watchdog tripped.
Again at 15:27
17:55 I found the PRM was oscillating while the watchdogs were not tripped. I turned off the OPLEV servos and this made the PRM calmed down. But I didn't turn on the OPLEVs for the past two trips. How were the OPLEVs turned on???
Ah, I'm sorry, I missed the line that Gautam was running the free-swinging test on the PRM.
The two kicks starting from 23:08:50 and from 23:26:31 were spoiled. Did it make the measurement completely waisted?
Stephen and I discussed the nominal heights of the BHD platform components.
Per Gautam's request, I've checked the coil resistances and inductances.
A DSUB25 breakout was directly connected to the flange (Attachment 1).
The impedance meter was nulled every time the measurement range and type (R or L) were changed.
Feedthru connector: PRM1
Pin1 - flange: R = 0.8Ω
Pin11-23 / R = 1.79Ω / L=3.21mH
Pin 7-19 / R = 1.82Ω / L=3.22mH
Pin 3-15 / R = 1.71Ω / L=3.20mH
Feedthru connector: BS1
Pin1 - flange: R = 0.5Ω
Pin11-23 / R = 1.78Ω / L=3.26mH
Pin 7-19 / R = 1.63Ω / L=3.30mH
Pin 3-15 / R = 1.61Ω / L=3.29mH
Feedthru connector: SRM1
Pin1 - flange: R = 0.5Ω
Pin11-24 / R = 18.1Ω / L=3.22mH
Pin 7-20 / R = 18.8Ω / L=3.25mH
Pin 3-16 / R = 20.3Ω / L=3.25mH
Feedthru connector: PRM2
Pin1 - flange: R = 0.6Ω
Pin11-23 / R = 1.82Ω / L=3.20mH
Pin 7-19 / R = 1.53Ω / L=3.20mH
Pin 3-15 / R = N/A
Feedthru connector: BS2
Pin1 - flange: R = 0.6Ω
Pin11-23 / R = 1.46Ω / L=3.27mH
Pin 7-19 / R = 1.54Ω / L=3.24mH
Pin 3-15 / R = N/A
Feedthru connector: SRM2
Pin1 - flange: R = 0.7Ω
Pin11-24 / R = N/A
Pin 7-20 / R = 18.5Ω / L=3.21mH
Pin 3-16 / R = 19.1Ω / L=3.25mH
The SRM pinouts seem mirrored compared to the others. In fact, these two connectors are equipped with mirror cables (although they are unshielded ribbons) (Attachment 2).
The SRM sus is located on the ITMY table. There is a long in vacuum DSUB25 cable between the ITMY and BS tables. I suspect that the cable mirrors the pinout and this needs to be corrected by the in-air mirror cables.
I went around the lab and did not find any other suspensions which have the mirror cable.
WIth the BHD configuration, we will move the feedthru for the SRM to the one on the ITMY chamber. So I believe the situation is going to be improved.
For magnet strength measurement: There is a gaussmeter in the flukes' drawer (2nd from the top). It turns on and reacts to a whiteboard magnet.
I've brought 4 DO-32L-PE cards from WB for BHD upgrade for Jon.
I want to emphasize the followings:
I'm going to remove REFL11 demod for the noise check/circuit improvement.
First I checked the noise levels and the transfer functions of the daughterboard preamp were checked. The CH-1 of the SR785 seemed funky (I can't comprehensively tell yet how it was), so the measurement maybe unreliable.
For the replacement of AD797, I tested OP27 and TLE2027. TLE2027 is similar to OP27, but slightly faster, less noisy, and better in various aspects.
The replacement of the AD797 and whatever-film resistors with LTE2027 and thin-film Rs were straightforward for the I phase channel, while the stabilization of the Q phase channel was a struggle (no matter I used OP27 or TLE2027). It seems that the 1st stage has some kind of instability and I suffered from 3Hz comb up to ~kHz. But the scope didn't show obvious 3Hz noise.
After a quite bit of struggle, I could tame this strange noise by adjusting the feedback capacitor of the 1st stage. The final transfer functions and the noise levels were measured. (To be analyzed later)
Now the REFL11 LO cable was replaced from the soft low noise audio coax (Belden 9239) to jacketed solder-soaked coax cable (Belden 1671J - RG405 compatible). The original cable indicated the delay of -34.3deg (@11MHz, 8.64ns) and the loss of 0.189dB.
I took 80-inch 1671J cable and measured the delay to be ~40deg. The length was adjusted using this number and the resulting cable indicated the delay of -34.0deg (@11MHz, 8.57ns) and the loss of 0.117dB.
The REFL11 demod module was restored and the cabling around REFL11 and AS110 were restored, tightened, and checked.
I've removed the PD mon cables from the NI RF switch. The open ports were plugged with 50Ohm temirnators.
Attachment 1: Transfer Functions
The original circuit had a gain of ~20 and the phase delay of ~1deg at 10kHz, while the new CH-I and CH-Q have a phase delay of 3 deg and 2 deg, respectively.
Attachment 2: Output Noise Levels
The AD797 circuit had higher noise at low frequency and better noise levels at high frequency. Each TLE2027 circuit was tuned to eliminate the instability and shows a better noise level compared to the low-frequency spectrum of the AD797 version.
RXA: AD797 , all hail the op-amps ending with 27 !
I've worked on packing the components for the following chassis
- 5 16bit AI chassis
- 4 18bit AI chassis
- 7 16bit AA chassis
- 8 HAM-A coil driver chassis
They are "almost" ready for shipment. Almost means some small parts are missing. We can ship the boxes to the company while we wait for these small parts.
And some more additional items to fill the emptying stock.
We have received 9x 18bit DAC adapter boards (D1000654)
I think the PSL HEPA (both 2 units) are not running. The switches were on. And the variac was changed from 60% to 0%~100% a few times but no success.
I have no troubleshooting power anymore today. The main HEPA switch was turned off.
- Last week we found both of the PSL HEPA units were not running.
- I replaced the capacitor of the north unit, but it did not solve the issue. (Note: I reverted the cap back later)
- It was found that the fans ran if the variac was removed from the chain.
- But I'm not certain that we can run the fans in this configuration with no attendance considering fire hazard.
@3AM: UPON LEAVING the lab, I turned off the HEPA. The AC cable was not warm, so it's probably OK, but we should wait for the continuous operation until we replace the scorched AC cable.
The capacitor replacement was not successful. So, the voltages on the fan were checked more carefully. The fan has the three switch states (HIGH/OFF/LOW). If there is no load (SW: OFF), the variac out was as expected. When the load was LOW or HIGH, it looked as if the motor is shorted (i.e. no voltage difference between two wires).
I thought the motors may have been shorted. But if the load resistance was measured with the fluke meter, it showed some resistance
- North Unit: SW LOW 4.6Ohm / HIGH 6.0Ohm
- South Unit: SW LOW 6.0Ohm / HIGH 4.6Ohm (I believe the internal connection is incorrect here)
I believed the motors are alive! Then the fans were switched on with the variac removed... they ran. So I set the switch LOW for the north unit and HIGH for the south unit.
Then I inspected the variac:
So, this scorched AC plug/cable connected directly to the AC right now. I'm not 100% confident about the safety of this configuration.
Also I am not sure what was wrong with the system.
So, while I'm in the lab today, I'll keep the HEPA running, but upon my taking off, I'll turn it off. We'll discuss what to do in the meeting tomorrow.
Basically I went around all the chambers and all the DB25 flanges to check the invac cable configurations. Also took more time to check the coil Rs and Ls.
Exceptions are the TTs. To avoid unexpected misalignment of the TTs, I didn't try to disconnect the TT cables from the flanges.
Upon the disconnection of the SOS cables, the following steps are taken to avoid large impact to the SOSs
After the measurement, IMC was lock and aligned. The two arms were locked and aligned with ASS. And the PRM alignment (when "misalign" was disengaged) was checked with the REFL CCD.
So I believe the SOSs are functioning as before, but if you find anything, please let me know.
5x 16bit ADC adapter boards (D0902006) assembled.
We received 10x 16bit ADC adapter boards from Todd. S2100687~S2100696
The number of soldered resistors seems to be less than that on the schematics. They are related to duotone, so check if it's OK upon use.
I was looking at the laser head/amp and somehow decided to open the glue freezer. And it was stuck. I've managed to open it but the upper room was completely frozen.
Some of the batteries were embedded in a block of ice. I think we should throw them out.
Can the person who comes in the morning work on defrosting?
- Coordinate with Yehonathan and move the amps and the wooden crate so that you can move the freezer.
- Remove the contents to somewhere (it's OK to be room temp for a while)
- Unplug the freezer
- Leave the freezer outside with the door open. After a while, the ice will fall without care.
- At the end of the day, move it back to the lab. Continue defrosting the other day if the ice remains.
PSL Shutter closed / MC Autolocker disabled / PSL mechanical shutter closed / Laser injection current turned to zero / Laser turn off (red button) / Laser key turned off
The laser stat before the shutdown:
- LD Temp A: Set 22.07 (Untouched)
- LD Temp B: Set 21.03(Untouched)
- Laser Injection Current: Dial 9.53, Actual 2.100 -> Dial was moved to zero upon shutting down
- Laser Crystal Temp: Dial 3.34 (untouched) Set 30.57 Actual 30.60 (Untouched)
PSL Table covering
- Because of the so many cables going up and down, sealing the PSL table with the metalized sheet was not easy. Therefore, the sheets have been just softly laid above the optics. (Attachment 1)
- The largest sheet which covers the east half of the table was taped to the table at the bottom, so that the air from the chimneys (see below) does not come up to the table
- The large dust could come from the opening of the enclosure during the filter replacement. So it was considered to be easier to seal the openings. (Attachment 2)
- Of course, the HEPAs are going to be tested after the maintenance work. It means that vent paths were needed so that the seals do not explode with the pressure (together with dust).
- Thus, the tubes of the sheets are attached to the seals to form "chimneys" for guiding the airflow beneath the table. (Attachment 2/3/4)
- This configuration was not meant to be sufficiently strong for a continuous run of the fans. Long running of the HEPAs may cause the failure of the seal tapes.
Therefore the HEPA test should be done with a low flow rate and/or a short period of high flow.
- Once the work has been done, all the sheets should be carefully removed without scattering the fallouts onto the optics.
I also located the (possible) HEPA filters in the lab. (Attachments 1~3)
Oh! This is NO-NO! We can't place anything in front of the mains breakers. (Attachment 2)
I relocated the objects (Attachment 3)
It's probably too late to say but there are/were two boxes. (just for record)
The new HEPA speed controllers are attached at the middle of the HEPA unit (not at the edge of the unit)... (Attachment 1)
You still need a step./stool to touch the knob and need a ladder for a more precise setting.
We still don't know the optimal speed of the nominal IFO operation. For now, the HEPAs are running at the max speed (Attachment 2).
Once we know the optimal setting, we mark the knobs so that we can see them only with the step.
New HV power supply from Company 'M' has been delivered. So I decided to compare the noise levels of some HV supplies in the lab. There are three models from companies 'H', 'K', and 'M'.
The noise level was measured with SR785 via Gautam's HP filter with protection diodes.
'H' is a fully analog HV supply and the indicator is analog meters.
'K' is a model with a LCD digital display and numerical keypad.
'M' is a model with a knob and digital displays.
All the models showed that the noise levels increased with increased output voltage.
Among these three, H showed the lowest noise. (<~1uV/rtHz@10Hz and <50nV/rtHz@100Hz) (Attachment 1)
K is quite noisy all over the measured freq range and the level was <50uV/rtHz. Also the PSD has lots of 5Hz harmonics. (Attachment 2)
M has a modest noise level (<~30uV/rtHz@10Hz and <1uV/rtHz@100Hz)except for the noticeable line noise (ripple). (Attachment 3)
The comparison of the three models at 300V is Attachment 4. The other day Gautam and I checked the power spectrum of the HV coil driver with KEPCO and the output noise level of the coil driver was acceptable. So I expect that we will be able to use the HV supply from Company M. Next step is to check the HV driver noise with the model by M used as the supply.
I believe that there is an internal setting for the minimum flow, so the flow is not linear ("0%" is not zero), but we should mark this flow speed once you find this is sufficiently low for the locking too.
The other day I felt hot at the X end. I wondered if the Xend A/C was off, but the switch right next to the SP table was ON (green light).
I could not confirm if the A/C was actually blowing or not.
I also noticed some sound in the control room. (didn't open the MP3 yet)
I'm afraid that the hard disk in the control room iMac is dying.
Did you match the local PC time with the GPS time?
No, this is the property of the suspension assembly. The mass says 10kg
Could you do the same for the testmass assembly (only the suspended part)? The units are good, but I expect that the values will be small. I want to keep at least three significant digits.
I believe I did the identical test with the one in [40m ELOG 15786]. The + input of PA95 was shorted to the ground to exclude the noise from the bias input. The voltage noise at TP6 was measured with +/-300V supply by two HP6209 and two Matsusada R4G360.
With R4G360, the floor level was identical and 60Hz line peaks were less. It looks like R4G360 is cheap, easier and precise to handle, and sufficiently low noise.
Calculation for the SOS POS/PIT/YAW resonant frequencies
- Nominal height gap between the CoM and the wire clamping point is 0.9mm (cf T970135)
- To have the similar res freq for the optic with the 3" metal sleeve is 1.0~1.1mm.
As the previous elog does not specify this number for the current configuration, we need to asses this value and the make the adjustment of the CoM height.