Frequency of DAC lock out events (requiring IOP model restart to fix). One more event (h1susb123) added since my last entry
12/11 2014 h1susb123
10/26 2014 h1seih45
9/11 2014 h1seih45
9/10 2014 h1seih23
8/11 2014 h1susb123
8/9 2014 h1seih23
4/21 2014 h1sush2a
3/18 2014 h1sush2a
2/27 2014 h1seih23
12/16 2013 h1seih23
11/7 2013 h1sush2a
11/7 2013 h2sush34
8/8 2013 h1seih23
This is regarding the BS suspension damping using its oplev.
I looked at the behaviour of HAM3 and BS oplev lasers over the last two hours.
The HAM3 laser (HAM3 oplev is the preferred test bed for the lasers we fix before we plug them into core optics suspensions) has an order of magnitude lower noise in the 10 to 100Hz band. The forest of peaks we see above 100 Hz are probably from the pier motion and not from the laser itself.
I have also looked at the 24 hr trend of the HAM3 oplev. There are a few glitches during the time people were working in the LVEA. I expect these will not be present when things are quiet.
Shifting the HAM3 oplev laser to BS oplev should improve the BS suspension damping.
Jeff K, Suresh, Sheila
The wind is picking up. We are having 60 mph gusts and can hear it on the roof, so that's for interferometery tonight. High winds started at around 2:50 UTC, December 12th.
J. Kissel, S. Doravari Hoping to take advantage of the windy night without interferometry I tried to start taking some long-needed acceptance transfer functions on the ITMs. However, I immediately discovered that the IOP outputs from the suspensions were zeroed out. Signals apparently dropped out at for all SUS on h1susb123, i.e. H1SUSITMX, H1SUSBS, and H1SUSITMY at the same time, roughly Dec 12 2014 02:52 UTC (Dec 11 2014 18:52:00 PST, GPS 1102387936 -- about when Sheila noticed that the ITM pitch motions were ~10 [urad] and started to blame the changes to SEI systems), see attached. I checked everything I'd checked last time there were loose wires in the software (see LHO aLOG 13329), but they didn't report any problems: (1) All SUS watchdogs are green (2014-12-11_H1SUSITMY_Overview.png) (2) All IOP Software Watchdogs are green (2014-12-11_SWWD_Status.png) (3) dmesg of h1susb123 doesn't report any badness (2014-12-11_h1susb123_dmesg.txt) (4) proc status seems happy (2014-12-11_h1susb123_procstatus.txt) I've called Dave and left a message. I'm going to do the same sledge hammer solution we did last time and kill all USER front end processes, restart the IOP model, and restart the USER models. I hate this -- we really need a way to reset this WD DACKILL look alive WITHOUT having to take down the entire front end...
S. Dwyer, K. Venkateswara
Sheila turned WFS on and locked the X-arm using the green laser. I then took measurements with and without the LLO sensor correction on ITMX and ETMX. I also tried out the low-frequency sensor correction (using Rich's SC filter and the tilt-subtracted sensor ), only at ETMX. ASD plots are attached showing various sensors. And a comparison of the control signal for the different configuraitons.
It is likely that ALS is not sensitive enough below 1 Hz to see the effect of the sensor correction.
I began realigning the PRC probe beam (sent into HAM2 via IOT2R) to the PRM. First of all I aligned the beam reflected from PRM and transmitted through IM4 back into the aux laser path, using an iris, centering on lenses, and the FI aperture as a guide. This required some significant repositioning of the lower IOT2R periscope mirror, because this was adjusted in order to dump the IM4 trans beam recently for the benefit of the ISS photodiode. I then turned on the aux laser and overlapped the main beam (as best as possible just by looking at the spots on a card at two locations). With the main beam now coarsely overlapped with the aux beam, I aligned it to the RFPD that is used to generate the main laser / aux laser beat signal, maximizing the DC output of the PD. I observed the RF output on the HP spectrum analyzer, but wasn't able to see a beat signal (this might require more tuning of the aux laser temperature offset). One thing I did notice, however, were big peaks in the spectrum at the 9MHz and 45MHz sideband frequencies. These peaks remained when the aux laser was turned off. Since this beam is just the forward beam from the IMC, one would hope that the RF sidebands were pure phase modulation... is this an indication of unwanted RFAM in the IMC trans beam already? I don't know for sure what the IFO state was when I observed this, though I do know that the PRM was deliberately misaligned by this time.
Filiberto and Aaron pulling cables in LVEA 07:41 Karen and Cris cleaning in the LVEA 08:30 Jeff B. to LVEA to swap dust monitors 08:41 Jeff B. back 08:48 Jeff B. to end Y to look at dust monitors 09:14 Corey and Suresh to the squeezer bay 09:17 Betsy to the LVEA 09:23 Jeff B. back from end Y 09:32 Betsy to mid Y 09:34 Christina, Cris and Karen to end Y for first cleaning of BSC10 09:52 Gerardo back from end Y (turned on clean room over BSC10) 10:08 Pepsi truck through gate 10:09 Betsy back from mid Y 10:41 Andres to high bay 10:41 First cleaning of BSC10 done 10:58 Andres back from high bay 11:08 Daniel and Elli to end Y to work on WFS 11:52 Cyrus upgrading firmware on surveillance cameras 12:08 Daniel and Elli back from end Y 12:42 Betsy to mid Y 14:47 Gerardo to H2 PSL enclosure David O., Elli and Greg working on HWS table near HAM6
The last couple of days Krishna and I have been working on sensor correction everywhere, but have been having troubles on HAM3. This is not exactly related to that effort, but we noticed that there is a very Q-y feature in the HAM3 ISI and SUS spectra. Jeff helped me dig into this and we are pretty sure this is not due to the suspensions, but it's been there the last couple of days, with and without sensor correction. It doesn't show in HEPI or the ground spectra, so I'm not sure where this comes from. When the IMC isn't being used I will try turning isolation loops off to see if the ISI is causing it. Attached spectra is of the MC2 suspension point(ISI GS-13's), but PR2, MC2 OSEMS and ISI CPS's see this, as well.
And by "pretty sure" it's not the SUS, Jim means "it's definitely not." The first HSTS modes are at 0.67 [Hz], and the recent design study (see G1401291) have revealed that even with crappy legacy damping filters and gains that are still in place, the Qs of all the modes are reduced well below what's seen here. Also of note -- The 0.6 [Hz], and 1.5, and 2.9 [Hz] features are seen in IMCL, PRCL, and the HAM Optical lever, so it's definitely the ISI, because it's common to both SUS in the chamber and their moving mass doesn't couple well enough to the ISI to move the thing in all DOFs like is shown here.
And now you don't!
I started looking for the .6hz whatsits and it's gone now. The local sensors didn't see it when I looked this morning, but looking back in time it disappeared some time between 16:00 (first plot) and 16:30 (second) yesterday. We are also seeing something similar on the ITMs' oplevs (third plot, you can see it in Krishna's post about Xarm sensor correction, too) now as well, so whoever fixed HAM3 should keep going.
A new type of filter block is now available in the real-time system. The Integrator Filter Module (IFM) implements a single integrator only, but has a couple of additional features compared to a standard filter module:
The attached screen shot represents the new IFM. The available parameters are
The testpoint and EPICS channel names are the same as in the standard filter module:
The SFM uses a bit encoded momentary switch for its enables. However, this requires state notation code support; and the IFM uses individual EPICS bi channels.
/* This is an integrator with output limiter and bleed off
Inputs:
1. Error signal (double)
2. Excitation input (double)
3. Request word (bit encoded int)
-----------------------------------------------------------------------
Bit Name Description
-----------------------------------------------------------------------
0 Filter Request for integrator to run
1 Input Switch Request for input switch to be on
2 Offset Switch Request for offset to be enabled
3 Limit Switch Request for the limit switch to be engaged
4 Output Switch Request for the ouptut switch to be on
5 Hold Output Request for the output to hold
6 Bleed Enable Request for filter to bleed off
7 Bias Enable Request for output bias to be on
15 Decimation Request for output decimation (8Hz single pole)
-----------------------------------------------------------------------
4. Offset input (double)
5. Gain input (double)
6. Unity gain frequency in Hz (double)
7. Bleed rate in cts/s (double)
8. Maximum absolute value/limiter (double)
9. Bias input (double)
10. Model rate in Hz (double)
Outputs:
1. Control signal (double)
2. IN1 ouptut (double)
3. IN2 output (double)
4. OUT ouptut (double)
5. Decimated control signal (double)
6. Status word (bit encoded int)
-----------------------------------------------------------------------
Bit Name Description
-----------------------------------------------------------------------
0 Coeff Reset not used.
1 Master Reset Momentary; when set, INT will reset all
filter history buffers.
2 Input On/Off Enables/disables signal input to INT.
3 Offset Switch Enables/disables application of INT input
offset value.
4 Filter Request Set to one when an INT filter is requested ON,
or zero when INT filter requested OFF
5 Filter Status Set to one by INT when an INT filter is ON,
or zero when INT filter is OFF
6 Limiter Switch Enables/disables application of INT output
limit value.
7 Limiter Status Set for 1 sec, when the limiter is enabled
and the output value became too large.
8 Decimation Enables/Disables application of decimation
Switch filter to INT OUT16 calculation.
9 Output Switch Enables/Disables INT output (INT OUT and
OUT16 variables)
10 Hold Output If (!bit 26 && bit27), INT OUT will be held
at last value.
11 Bleed Enable If set, the accumulated integrator value will
be bled off with the specifed bleed rate
12 Bias Enable If set, a bias will be added to the output
-----------------------------------------------------------------------
*/
#define INTFILTER 0x01
#define INTINPUT 0x02
#define INTOFFSET 0x04
#define INTLIMIT 0x08
#define INTOUTPUT 0x10
#define INTHOLD 0x20
#define INTBLEED 0x40
#define INTBIAS 0x80
#define INTDEC 0x8000
#define PI 3.1415926535897932384626433832795028841971693993751058
#ifdef _WIN32
typedef enum {false, true} bool;
#define isnan(s) 0
#define printk(s)
#endif
bool myfinite (double s)
{
// By IEEE 754 rule, 2*Inf equals Inf
return !isnan(s) && ((s == 0) || (s != 2*s));
}
void Integrator (double* in, int ins, double* out, int outs)
{
/* INPUT and OUTPUT vars for Integrator function block */
double inval = 0.0;
double exc = 0.0;
int req = 0;
double ofs = 0.0;
double gain = 0.0;
double ugf = 0.0;
double bleed = 0.0;
double limit = 0.0;
double bias = 0.0;
double rate = 16384;
double outval = 0.0;
double in1 = 0.0;
double in2 = 0.0;
double out1 = 0.0;
static double out16 = 0.0;
int stat = 0;
/* local vars */
static int error = 0;
static double oldout = 0.0;
static double holdval = 0.0;
static int limcount = 0;
double val = 0.0;
double g = 0.0;
/* argument check */
if ((ins != 10) || (outs != 6)) {
if (!(error & 0x1)) {
printk("Integrator: wrong number of inputs and/or outputs\n");
error |= 0x1;
}
return;
}
// Read input values
inval = myfinite (in[0]) ? in[0] : 0.0; // must be finite
exc = myfinite (in[1]) ? in[1] : 0.0; // must be finite
req = (int) (myfinite (in[2]) ? in[2] : 0); // must be finite
ofs = myfinite (in[3]) ? in[3] : 0.0; // must be finite
gain = myfinite (in[4]) ? in[4] : 0.0; // must be finite
ugf = myfinite (in[5]) && (in[5] > 0) ? in[5] : 0.0; // must be finite and non-negative
bleed = myfinite (in[6]) && (in[6] > 0) ? in[6] : 0.0; // must be finite and non-negative
limit = myfinite (in[7]) ? (in[7] > 0 ? in[7] : -in[7]) : 0.0; // must be finite, take abs
bias = myfinite (in[8]) ? in[8] : 0.0; // must be finite
rate = (in[9] >= 0) ? in[9] : 1.0; // must be finite and positive
// Add offset and muliply with gain
val = inval;
if (req & INTOFFSET) {
val += ofs;
}
val *= gain;
// input switch and input test points
in1 = val;
if (!(req & INTINPUT)) {
val = 0.0;
}
val += exc;
in2 = val;
// Calculate filter
if (req & INTFILTER) { // filter on
g = 2*ugf/rate;
if (g > 1) { // ugf above Nyquist!
g = 1.0;
}
oldout = oldout+PI*g*val;
}
else { // filter is off
oldout = val;
}
// enforce limits when on
if (req & INTLIMIT) {
if (oldout < -limit) { // lower limit exceeded
oldout = -limit;
limcount = (int)rate + 1;
}
else if (oldout > limit) { // upper limit exceeded
oldout = limit;
limcount = (int)rate + 1;
}
}
if (limcount > 0) {
--limcount;
}
// Bleed off integrator value if selected
if (req & INTBLEED) {
g = bleed/rate;
if (oldout > g) {
oldout -= g;
}
else if (oldout < -g) {
oldout += g;
}
else {
oldout = 0.0;
}
}
// Output testpoint
out1 = oldout;
// Output enabled
if (req & INTOUTPUT) {
val = oldout;
}
else {
val = 0.0;
}
// Add bias if selected
if (req & INTBIAS) {
val += bias;
}
// Hold output if selected
if (req & INTHOLD) {
outval = holdval;
}
else { // no hold
outval = val;
holdval = val;
}
// Compute decimated output: 8Hz single pole low pass
if (req & INTDEC) {
g = 2*8.0/rate;
if (g > 1) {
g = 1.0;
}
g *= PI;
out16 = (1-g)*out16+g*outval;
}
else { // no decimation
out16 = outval;
}
// Set status
stat = 0;
stat |= (req & INTINPUT) ? 0x0004 : 0;
stat |= (req & INTOFFSET) ? 0x0008 : 0;
stat |= (req & INTFILTER) ? 0x0010 : 0;
stat |= (req & INTFILTER) ? 0x0020 : 0;
stat |= (req & INTLIMIT) ? 0x0040 : 0;
stat |= limcount ? 0x0080 : 0;
stat |= (req & INTDEC) ? 0x0100 : 0;
stat |= (req & INTOUTPUT) ? 0x0200 : 0;
stat |= (req & INTHOLD) ? 0x0400 : 0;
stat |= (req & INTBLEED) ? 0x0800 : 0;
stat |= (req & INTBIAS) ? 0x1000 : 0;
// Write output values
out[0] = outval;
out[1] = in1;
out[2] = in2;
out[3] = out1;
out[4] = out16;
out[5] = stat;
}
Here is the corresponding simulink block.
Hanford transportation will haul on day shift and swing shift on Friday 12/12, and ERDF will operate a Friday day shift. No weekend work is scheduled.
Kiwamu, Dave O, Elli
Here are better quality images of ETMx. These images were taken with the same method as for the ETMy images in alog 15547. The exposure level was 500000 microseconds (compared to 10000 for ETMy.)
The camera isn't well focused, because we choose to increase the camera apperature to maximum, which limited our ability to focus.
I was trying to understand a strange temperature bump at MIDX VEA and Richard noticed that there had been a very abrupt excursion outside.
This event turned out to be responsible for the VEA bump I observed at MIDX. The outside temperature rose from 42F to 54F in about 45 minutes
Take a look at these two outside temperatures from X and Y recorded yesterday around 8 pm.
The end stations were not affected since we still have chillers operating there.
JimW did this Tilt Decoupling 14 April; those values he came up with have managed to survive and were still in the CPS Align Matrix. Since we've done lots of changes in many places, we thought a check of tilt decoupling was in order. This morning I repeated the measurement and adjusted the numbers around these historic values. I changed both RX & RY decouple numbers at the same time during the tests.
The first attached is the results for driving in the Y direction. The left column is for the in line coupling; that is, pitching response adjusted by the RX-Y component of the ALIGN matriix. The right column shows the cross response--rolling about the Y axis adjusted by the RY-Y Matrix element.
The blue traces are with the original values, -.001/.0005 for RX/RY to Y elements. Green is the change to -.0015/.00075; brown are with the elements at -.0005/.000 for RX/RY.
The red traces are with the final desired values. Looking at the left inline values, the original blue trace with RX-Y at -.001 looks best. For the cross term RY-Y, it looks best at .00075 shown on the green trace--notice the greatly reduced coherence and lowered amplitude in the lower right and upper right plots respectively. When these 'best' values are used for the red results, things don't look quite as good as the green and the blue but may be the best compromise. This really shows the couplings here and the pain given the length of these measurements.
The second attachment shows driving in X. The blue curves show the original values for RX-X & RY-X. These are the best numbers as my bracketing around these makes the coupling higher seen in the green and red curves: The left column has the blue most linear and in the right column you see the lowest coherence and magnitude for the blue as well.
Templates for these measurements are in /ligo/svncommon/SeiSVN/seismic/BSC-ISI/H1/ETMY/Data/Transfer_Functions/Measurements/Tilt_Decouple/
As a preparation for doing some DRMI ASC, I've added a loop that servos SR2 to the AS_C QPD. (see LLO alog 15840)
As Keita centered AS_C after he finished unclipping the output arm (alog 15145), we can servo SR2 to this QPD to avoid clipping on the Faraday. The input and output matrix elements are 1, the output goes to M2, the gain for PIT is 500 and Yaw is 3000. These are both low bandwidth loops for now. The hope is that this will make using WFS to control the SRM more robust, as was seen at LLO. We'll see when we get a chance to lock DRMI.
After several false starts the new auto-centering software is finally ready to go. The attached screen shot shows the new medm screens. The screen to the left is the main servo screen. It shows the DC readouts of the WFSs leading to pitch and yaw matrices which then are fed into the new integrator filter modules (IFM). The screen to the right shows the new trigger logic. The auto centering is engaged automatically, when there is enough light on the WFSs, when the IFMs are in auto mode and when the main enable switch is on. This SUM thresholds are adjusted on the trigger screen. Whenever the SUM trigger is off, the corresponding integrators are bled off. This ensures that they come back to a good state, if they get completely out of alignment. The later is sometimes introduced by a misalignment of the ETM.
The RMS thresholds are used to decide, if the PZT servos have settled. The logical AND of all triggers is sent to the WFS servos as an additional trigger to engaged the alignment servos.
The attached pdf shows a typical transfer function of an auto-centering servo with a ugf of 10 Hz.
Elli, Daniel
We noticed that PZT2 used for centering WFS_B in end X was out of alignment range. We were tapping at different mounts to see if something was flaky. Indeed, we found that the PZT mirror was not very well attached. This is a press-fit mount and had too much slack. We jammed in a piece of plastic material and realigned the path.
Evan, Alexa
Following the preparation described in alog 15524, we made a ringdown measurement of both the x- and y-arm. For each arm, we locked the IR beam and ran the wfs to ensure maximum build up. We then turned the wfs off, and switched the input polarity of the MC common mode board to unlock the MC quickly (based on LLO's alog 11727 the MC has about a 15usec ringdown time). We used the relfected signal at the AS port to capture the ringdown. We repeated this measurement 10 times to have ample data for our uncertainities. We also measured the "off-resonance" ringdown, by unlocking the arm and misaligning the respective ETM. All the data can be found in /ligo/home/alexan.staley/Public/Ringdown/EX(Y)data (these folders are then split into locked and unlocked times). From this data we calculated the total loss:
X arm: 14310(100) ppm
Y arm: 15000(100) ppm
Based on the galaxy ITMY transmissivity (1.42%) this amounts to 800ppm of loss in the y-arm. Meanwhile, for the x-arm, the ITMX transmissivity is 1.39 % corresponding to a 410ppm loss in the arm. We are in the process of calculating the transmissivity of the ITMs based on our ringdown fit. Our code can be found in /ligo/home/alexan.staley/Public/Ringdown/proccess.py. The y-arm losses seems consitent with our scan measurements; however the x arm does not. These numbers are very sensitive to the transmissivity we use; so before we make an conclusion with this we should inprove our confidence in the transmissivity values.
I’ve attached the code, the data, and the plots in a zip file.
Also attached are a few representative plots with the arms locked and unlocked.
Also, Dave wants me to note that the inferred loss of 410 ppm in the X arm is probably wrong; we’ve just pulled the ITMX transmissivity from the galaxy website instead of extracting it from our data. This is in progress.
The time constant of the ringdown is half of the cavity storage time, and the cavity storage time is related to the arm reflectivities by an equation in Isogai (sec 4.3):
We've assumed that we know RE = 1 − 5×10−6.
Here are the values for the ITM transmissivities, as inferred from the ringdown data.
In summary, to within experimental error there is no anomalous loss in the X arm. In the Y arm, the anomalous loss is 1330(370) ppm.
An updated version of the code is attached, along with a document giving the expression for TITM in terms of the measured quantities.
Here I've assumed RETM = 1, as was done in the paper by Isogai et al.
[Edit: Alexa has pointed out that we need to use m1 = RITM(P0+P1), rather than the original Isogai formula m1 = P0+P1, since we are using a PD in reflection. I've updated the table and the attachments accordingly. The ITM transmissivities change slightly and the extra losses go up a bit, but the conclusions remain the same.]
X arm | Y arm | |
---|---|---|
m1 | 201(5) mV | 153(5) mV |
m2 | 70(13) mV | 467(30) mV |
m3 | 203(16) mV | 114(12) mV |
m4 | 1.863(13) ms | 1.778(12) ms |
ITM transmission, TITM | 1.419(35) % | 1.366(36) % |
Total loss, L | 14 310(100) ppm | 14 990(100) ppm |
L − TITM | 120(360) ppm | 1330(370) ppm |
For posterity, the old, incorrect values for the ITM transmissions were 1.425(35) % for X and 1.37(4) % for Y. The incorrect values for the extra losses were 60(360) ppm for X and 1290(410) ppm for Y.
Check the assumption on ETM transmission? Our measurement is 3.6 ppm with a tolerance of 0.2 ppm for both LHO ETMs. https://dcc.ligo.org/LIGO-E1300313
Dan, Kiwamu,
We locked the PRMI on the sidebands to assess the current recyclying gains. The result will be posted later.
We did the initial alignment sequence to get back to a good global interferomter alignment. One thing I have to note is that I had to touch PR3 in yaw by 2 urads in order to recover a high RF power in ALS COMM. It is now back to 3 dBm in the monitor. Also this gave a good spot position on the ALS X camera as it was clipping before I moved PR3. The clipping seems to be fixed now on the camera. I aligned TMSY, ETMY and ITMY using the green light with a hope that they still represent a good IR alignment. After going through all the alignment sequence, the ALS DIFF beatnote came back to a high RF power of about 0 dBm. So I think the global alignment came back to as good as before.
The PRMI was locked very easily by setting LSC_CONFIGS to PRMI_sb_OFFLOADED. Then we aligned the OMs and did OMC scans in order to evaluate the recyclying gains. The data is now under some analysis. After the OMC scan, we attempted to lock the PRMI on the carrier, by simply flipping the sign of the PRCL control sign. We tried different gain settings MICH which uses REFL45Q, but did not get good lock tonight. So, we still don't know the carrier recycling gain.
We locked the PRMI on carrier. The carrier recyclying gain was measured to be 35 at highest. However, since the alignment was not perfect, it probably would go up. To be continued.
After playing with the gain settings, we eventually became able to lock the PRMI on carrier. However the alignment was not stable to keep it locked with high build-up. I think this needs more study to understand what is going on. Anyway, so far, the highest buidl-up in POPAIR_A_LF we had tonight was about 3.5x104 uW. When the simple MICH without power-recycling was locked, POPAIR_A_LF was about 30 uW. Assuming that there is no mode-mismatch and Tp=0.03, we get a recycling gain of 3.5x104 / 30 * Tp = 35.
LSC settings:
Attached are the OMC scan results for a PRMI sideband lock, compared to a scan from a single-bounce beam. The first plot shows the results of three single-bounce scans and three PRMi scans (100 second ramps of PZT2); the second plot has averaged the traces. The PRMI data appears to be shifted upwards compared to the single-bounce data, by about 1V in the PZT2 output. We expect some drift and hysteresis in the PZT, but the single-bounce data was taken immediately after the PRMI lock, and a shift of this size is...surprising.
Using Kiwamu's expression from alog:14532, I calculate the PRC gain of the 45MHz sideband to be about 11.8 or 14, depending on which sideband peak you use. I think this is lower than we expect. The PRMI sideband lock was quite wobbly with a lot of angular motion, we might get a more robust measurement by locking the OMC to a particular mode and maximizing the transmission.
Here is a table of peak heights:
Sideband Freq. | Single-bounce data | PRMI Data |
-45 | 0.31 | 3.98 |
-9 | 0.17 | 2.45 |
9 | 0.17 | 0.22 |
45 | 0.31 | 4.70 |
With a Schnupp asymmetry of 9.5cm the gain, for example for the upper 45MHz sideband, is (4.7/0.31) * (0.03*0.5*0.5) * (1/sin(2*pi*0.095*5*9100230/c)**2) = 13.9.
Just for a book-keeping purpose:
Two weeks later from this entry, we have measured the recycling of the carrier with the ASC loops fully engaged. We measured it to be 45 (see alog 15793).
As proposed, WFSA (hard sensor) is fed back to the ITMX and WFSB (soft sensor) to the TMSX.
In the attached, you can see that even when I made a terrible kick such that the transmission dropped below 50%, it eventually came back on its own.
Short lock losses don't kick the WFS out of range, and as of now it is maintaining green transmission between 1.15 and 1.18 for 30 min.
ITMX beam position control (fed back to ETMX) is not implemented yet, but should be easier than WFSs themselves.
Eventually we might be able to change the scheme such that hard is fed back to hard, soft to soft, and then ITM beam position to TMS, but I'm doing it this way as it is easier.
Before doing camera, however, I'll move to Y arm.
The X arm green WFS are running again this afternoon, and they did bring the cavity to a high build up. I reduced the gain from 0.5 to 0.25 because it oscillated when I first turned it on. I've edited the guardian to turn this on and off.