Attached is ten days of minute trends for some channels at EndX and EndY for the HEPI Pump systems.
At EndX, the Pump is still controlled(Ch2) by the last pressure sensor on the Pump Station skid(Ch1.) At EndY, the control was switched early Thursday to the actual differential pressure across the actuators measured in the VEA (Ch5.) On Friday, you can see where I smoothed the Supply & Return pressures and the Max/Mins of the differential pressure and the subsequent drive to the Pump Motor. It looks like the diurnal temperature fluctuations are increased significantly when the daily fluctuations or the daily minimum exceed some threshold.
We still have room to improve the grounds noise but I don't believe there is any reason not to switch all the Pump Stations to the differential control.
no restarts reported
model restarts logged for Sat 08/Nov/2014
2014_11_08 00:27 h1fw1
2014_11_08 17:29 h1fw1
both unexpected restarts.
Nic, Evan
We have gotten DRMI to lock on the 3f signals using the new, modified BBPD serving as REFLAIR_B.
Some good UTC times for 3f locking: 2014-11-09 0:56:50, 01:13:10, 02:41:00
Judging by POPAIR_B_RF18_I_ERR, the lock is kind of ratty both on 1f and 3f.
I think the reason Alexa and I couldn't lock yesterday is that we had the wrong relative gain for RF135Q/RF45Q. Nic and I remeasured it today and got 2.0. It is still true, however, that the ramping matrix doesn't give the expected behavior; it seeems to approach the requested value almost asymptotically, taking far longer than the specified ramp time.
We then adjusted the gains in the 3f input matrix to reduce gain peaking in the demodulated spectra of RF27 and RF135. We have written the following matrix elements into the lscparams guardian file:
Attached are our measured OLTFs of PRCL, MICH, and SRCL while locked on 3f. The DTT files are in my directory under Public/2014/11/DRMI3f
.
model restarts logged for Fri 07/Nov/2014
2014_11_07 06:28 h1fw1
unexpected restart of h1fw1, first one since Monday.
Alexa, Daniel, Evan
In order to use the new REFLAIR_B, we have made the following changes:
PRCL | SRCL | MICH | |
RF27I/RF9I | −0.49 | −3.9 | |
RF135I/RF45I | 2.4 | ||
RF135Q/RF45Q |
|
The RF27I/RF9I measurement for SRCL is low SNR for some reason. [Edit, 2014-11-05: I think I must have taken the RF135Q/RF45Q measurement upside-down. I retook it today and got a magnitude of 2.0.]
By using these gain measurements to adjust the DRMI 1f matrix elements, we have tried to transition from DRMI 1f to DRMI 3f. Howver, so far it keeps dropping lock.
The demodulated 1f and 3f spectra (taken while DRMI is 1f locked) are attached (units are cts/rtHz).
Something funny is going on with the LSC_INPUT_MATRIX. The ramping is not correct, plus it loads without the user request (and it's not the guardian)...
I was almost able to transition PRCL from 1f to 3f with a ramp of 10 and gain of -6.0 in the 3f signal, but it started to mode hop and lost lock. We probably should have touched-up alignment before trying to transition.
(Keita Daniel)
A spare BBPD with serial number S1200247 has been modified by removing and bypassing U1, the first RF amplifier stage. The attached BBPD_tf1.pdf file shows the transfer function before and after. Plot tf2 shows the ratio.
We took a baseline intermodulation product measurement by sending a two tone signal into the AM laser. The first tone was at 45 MHz and generated a line with -15 dBm amplitude. The second tone was a 90 MHz line also at -15 dBm. Plot IP2.png shows IP2 and IP3 lines at 135 MHz and 180 MHz with amplitudes of -57 dBm and -60 dBm, respectively.
The plot labeled IP2M shows the same measurement after the removal of U1. Close-in plots IP2M135 and IP2M180 show spectra with lower resolution bandwidth. The intermodulation lines are visible at a level around -115 dBm. One might consider this an upper limit, since the dominant distortion could be in the AM laser head. The IP2M135A plots shows one of the lines moved by 100 Hz. This now separates IP2 (lower frequency) and IP3 lines.
Finally, the IP2Mplus plot includes 20 dB higher drive levels to bring the lines back to -15 dBm. The 135 MHz lines shows up at -90 dBm which seems puzzeling low compared to the above measurement.
Modification pictures.
At Caltech, optical tests for a BBPD unit with the equivalent modification was done.
27MHz: Transimpedance 226Ohm, Shot noise intercept current 0.63mA
135MHz: Transimpedance 98.5Ohm, Shot noise interept current 3.8mA
These numbers are as expected.
In the attachments the following results are found:
- Schematic diagram
- Transimpedance (0.1-500MHz)
- Current noise level
- Transimpedance/Shot noise intercept current measurement with incandescent light at 27MHz and 135MHz
- IP2/IP3 measurement (same as before)
BBPD S1200234 has been replaced with BBPD S1200247 on the ISCT1 table. This will be our new REFLAIR_B.
Daniel has modified #247 by removing the MAR-6SM amplifier. From Koji's measurements (LHO#14901), we expect this to increase the IP2/IP3 of the amplifier chain and therefore lower the intermod products in RF27 and RF135.
The dc readout should be the same (i.e., we expect to read out ≈ 27 mW from the PD), but the rf readouts should be reduced by a factor of 10 in amplitude.
After installing, I resteered the beam (both in pitch and yaw) onto the PD using REFL-M3.
(For Evan and Nic)
Our current alignment procedures:
1. Lock green to both arms. Make sure all the sus guardians are in the proper configuration, ie. SUS_ETMs, SUS_ITMs, and SUS_TMSs are all aligned. H1:ALS-X_TR_A_LF_OUTPUT should be a little above 1 cnts, H1:ALS-Y_TR_A_LF_OUTPUT will be a little below 1 cnt. Align ITMs and ETMs as needed (if hopless, check TMS alignment on ITM baffle PD1 and PD4). Make sure both ALS_XARM and ALS_YARM guardians are set to LOCK_NO_SLOW.
2. After you are satisfied with the green alignment, make sure LSC_CONFIGs guardian is managed, and run ISC_DOF guardian to INPUT_ALIGN. This should lock the IR to the x-arm and misalign the y-arm cavity. You should see LSC-X_TR_A_LF_OUT go to around 1cnts. This will start the asc wfs and adjust IM4, PR2 to improve IR input alignment. Verify that LSC_ASAIR_A_LF_OUTPUT goes about 4,000 cnts. Then on ISC_DOF run SAVE_INPUT_ALIGN, this will offload the asc wfs to the alignment sliders. You MUST save the alignment values (ASC --> IFO_ALIGN.adl).
3. Then, on ISC_DOF run PRM_ALIGN. This will first lock PRX and engage the asc wfs for PRM to maximize the power buildup in LSC_ASAIR_A_LF_OUTPUT. Once you are satisfied with the power buildup, run ISC_DOR OFFLOAD_PRM so that the wfs are offloaded to the alignment sliders, again you must save the new alignment.
4. Set ISC_DOF to DOWN, and LSC_CONFIGS to MICH_DARK_LOCKED. Using the AS_AIR camera align the BS manually and save your new alignment values.
5. Return to ISC_DOF and run SRM_ALIGN. This will first lock SRY and engage the asc wfs for SRM to maximize the power buildup in LSC_ASAIR_A_LF_OUTPUT. Once you are satisfied with the power buildup, run ISC_DOR OFFLOAD_SRM so that the wfs are offloaded to the alignment sliders, again you must save the new alignment. (This step only required for DRMI locking).
FOR PRMI SIDEBAND LOCK: Set ISC_DOF to DOWN, set LSC_CONFIGS to PRMI_SB_OFFLOADED
FOR DRMI: Use ISC_DRMI and go to desired state. You will need to align various optics on your own because this guaridan does not manage any of the sus states.
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ALS_COMM guardian runs on its own, and can be set to IR_FOUND.
ALS_DIFF can be set to the LOCKED state. You will need to enter the LSC input matrix (H1:LSC-PD_DOF_MTRX_SETTING_1_28) on your own. At the moment the script leaves this as zero since our gains have been changing. The LSC_DARM boosts are also currently commented out.
-----------------------------------------
A useful striptool: /ligo/home/alexan.staley/Public/StripTemplate
*note: Observation Intent Bit was set to "green" at some point last night. The aLog did not reflect this action. Also, aLog crashed sometime after 10:55 last night.
*note: Intent bit was not set to "commissioning" until 08:39
*Suggest that notification be posted for cleaning crews at main access points IF actual intention is for NO acces to (L)VEAs be granted as long as OIB is set to "green"
*note: Accesses made to LVEA while OIB set to "green": (this is purely FYI as cleaning crews have generally been given access prior to 08:00AM.)
06:43 Cris into LVEA
07:08 Cris out of LVEA
07:09 Cris into LVEA
08:00 Daily Checklist performed. (Observation Intent Bit*) Nothing out of the ordinary to report. Every point functioning nominally.
08:!5 Betsy into LVEA
08:25 Karen into LVEA
08:32 Betsy out of LVEA
08:33 Karen out of LVEA
08:39 Observation Intent Bit set to "commissioning"*
09:00 Jeff and Andres into LVEA
09:12 Kyle headed to both end stations
09:18 Fil out to EX
09:50 Fil back from EX
09:58 Kyle back from Ends
10:00 Reservation System used to note commissioning activity
10:20 Suresh into LVEA w/comm appr
10:20 Mitch out of LVEA
10:14 Dale informed me of a group of high schoolers in for a tour ~13:00ish.
11:03 Corey out to LVEA w/comm appr
11:18 Suresh out of LVEA
11:30 Kyle informed me of a chilled water leak in the mechanical room. This leak is non-consequential to anything critical and he should have it repaired sometime after lunch.
11:31 Jeff and Andres out of LVEA
12:23 Krishna headed to EX. Not going into VEA.
12:51 Suresh backk into LVEA
13:37 Jeff and Andres into LVEA w/comm appr
13:38 Dale with tour group into control room ~10min
14:28 Jeff and Andres out of LVEA
15:30 Corey in control room with tour ~5min
15:39 Corey with tour out to roof.
I put 0.75 smoothing on the Supply & Return Pressuresmthat calc the differential pressure this morning. I couldn't smooth the calc'd channel with CAPUT, it may be better to smooth it directly but it may only be possible with a database change. I'll run this way for the weekend and see how things look overnight.
The week of 11/10 - 11/17 the LVEA will be split into a Laser Hazard area (South and East bays) and Laser Safe area (Beer Garden, North and West bays)as described in the TSOP M1400342. This split safe/hazard will be during the morning hours of 08:00 to 12:00 and there will be partitions with signage in place marking the boundaries of the two zones. During these hours additional barriers restricting foot traffic will be in place along the south wall starting at BSC1 and in the west bay between HAM-12 and the Y-Arm Spool.
We quickly looked at the damping filters we have on ETMX to compare to the L1 version. Things are pretty similar, other than 60 Hz notches and different gains. In yaw LLO uses a factor of 4 more gain, in length we have a factor of 2 more gain, in pitch we have a factor of 3 more gain.
I wanted to see if our ETMY F2P problems were saturation related. So I looked at the current monitors for the L1 OSEMs.
One thing that was quickly noticed is that while the three others show <100 counts in the readback when there is no drive signal, the LR coil shows -4000 counts. (For scale, saturation occurs around 13000 counts for the three normal looking coils).
This would seem to indicate some problem, possibly removing a third of our range in one direction of one of our coils. However, when you actually drive the coils to saturation, they all seem to have the same range from the point of view of the DAC, just with LR readback offset from zero by 4000 counts.
So this could just be a problem in the readback, not clear without looking at the analog electronics.
J. Kissel, N. Smith-Lefebvre After Nic showed me some of the details of what he found, I saw that a lot of the channels had an offset of not just 4000 [cts], but an infamous value 4300 [ct]. This could very well be an old nasty problem in the analog electronics where one leg of the SCSI connector on the back of the ADC card in the IO chassis shorted. It's best described here: LLO aLOG 1857 Most likely these offsets have been there since these chassis were first cabled up, and never fixed. Other instances where this bug bit us: LHO aLOG 5385 LLO aLOG 1853 I'll add this to Integration Issue 9, which continues to gather dust.
(Alexa, Evan, Sheila)
We made a transfer coeffecient measurement of the M0, L1, L3 stages for both of the ETMs so we can make a full comparison of the current confirguration we have. We excited in each LOCK stage at a frequency of 0.33 Hz (with no filters turned on), and took a transfer function of the oplevs in pith and yaw relative to the green arm locking control signal. The results are as follows:
ETMY:
Pitch (Mag urad/umeter, Phase deg) | Y (Mag urad/umeter, Phase deg) | |
M0 | (0.0336, 39.9) | (0.004, 164.2) |
L1 | (0.272, -125.5) | (0.0277, 30) |
L3 | (2.6, -179.6) | (0.017,63.1) |
ETMX:
Pitch (Mag urad/umeter, Phase deg) | Y (Mag urad/umeter, Phase deg) | |
M0 | (0.20(1), -19(1)) | -- |
L1 | (0.5(1), 36(2)) | -- |
L3 | (2.9(1), 0(1)) | -- |
Evan found no coherence between his excitations and the yaw oplev which is why those results are empty.
Conclusion: The ESD stage has the worst response for both ETMs in pitch, followed by L1. In Yaw, ETMY L3 and L1 are equally bad. ETMX seems to be worse than ETMY. This is a bit surprising since we only see green transmission drifts in the y-arm when we lock DIFF. One important thing to note is that we do not actuate on L3 at this frequency in ALS DIFF since the crossover between L1 and L3 is around 2 Hz as noted in alog.
For reference the templates can be found under: /ligo/home/sheila.dwyer/ALS/HIFOXY/ETMY_L2AngleNov72014.xml and /ligo/home/evan.hall/Public/2014/11/ETMX_L2P.xml