A few days ago the first 2 plates for LHO's next BSC were brought to the staging building. The first of these (D0900894-v2, s/n 1) was placed on the granite table today, and will be helicoiled over the next couple weeks, in between work on other install tasks. We won't really be able to get back into production of BSC's until at least one of the test stands can be switched back to a BSC configuration, but that is hopefully no more than a week or two out.

Pulled SUS PR2-TOP 25DB cable (CAB_H1:SUS_HAM3-3), from HAM3 Field Rack to HAM3 SUS assembly/testing area. Cable was routed to clean room but NOT connected to the mockfeedthru, since it requires full garb inside the cleanroom.

Since the suspension had been moved from the staging building test stand to the LVEA test stand (which utilized production electronics), I rechecked and tweeked the OLV offsets and the gains.  Today's measured OLVs and their channels are listed below:

27693  H1:SUS-MC2_M1_OSEMINF_T1_OUTMON (was -13851, set to -13846)

gain was 1.083, set to 1.083

22937  H1:SUS-MC2_M1_OSEMINF_T2_OUTMON (was -11462, set to -11468)

gain was 1.309, set to 1.308

28101  H1:SUS-MC2_M1_OSEMINF_T3_OUTMON (was -14049, set to -14050)

gain was 1.068, set to 1.068

26782  H1:SUS-MC2_M1_OSEMINF_LF_OUTMON (was -13383, set to -13391)

gain was 1.121, set to 1.120

27729  H1:SUS-MC2_M1_OSEMINF_RT_OUTMON (was -13847, set to -13864)

gain was 1.083, set to 1.082

30198  H1:SUS-MC2_M1_OSEMINF_SD_OUTMON (was -15085, set to -15099)

gain was 0.994, set to 0.993

24246  H1:SUS-MC2_M2_OSEMINF_UL_INMON (was -12413, set to -12123)

gain was 1.208, set to 1.237

23231 H1:SUS-MC2_M2_OSEMINF_LL_INMON (was -12030, set to -11615)

gain was 1.247, set to 1.291

23466 H1:SUS-MC2_M2_OSEMINF_UR_INMON (was -12152, set to -11733)

gain was 1.234, set to 1.278

25039 H1:SUS-MC2_M2_OSEMINF_UL_INMON (was -12977, set to -12519)

gain was 1.156, set to 1.198

24397  H1:SUS-MC2_M3_OSEMINF_UL_INMON (was -12411, set to -12198)

gain was 1.209, set to 1.230

23153 H1:SUS-MC2_M3_OSEMINF_LL_INMON (was -11815, set to -11576)

gain was 1.270, set to 1.296

25610 H1:SUS-MC2_M3_OSEMINF_UR_INMON (was -13089, set to -12805)

gain was 1.146, set to 1.171

19328  H1:SUS-MC2_M3_OSEMINF_UL_INMON (was -9727, set to -9664)

gain was 1.542, set to 1.552

Turned on Hepa fan on table at approximately 0930  while accessing the table for pictures of feed through s returned at 1205 to turn off fan while John W opened the gate valve.  The fan is now off.

H1 and H2 DAQ.

all four frame writers (h[1,2]fw[0,1]) are showing instability. I have extended their raw minute trend update periods to 30 minutes. The new configuration will be applied if any of them restart due to the original problem.

This morning Thomas told me that ETMY OPLEV MEDM screen was not working.

Though the medm screen for new OPLEV channels are present (H2SUSETMY_ETMY_L3_OPLEVWIT_P and Y, what's this stupid ETMY_ETMY thing anyway?), and though the output of the QPD segmens looked OK, the INMONs of OPLEVWIT_P and Y were zero, and more outrageously, the outputs were 1E20 though the gains were 1 and there was no filters. As soon as we set the gain to anything except 1.0, the output becomes zero. Some serious stupidity was going on.

We found that the signs of the oplev segments were all wrong, but that didn't fix this 1E20 thing.

On a deeper inspection we've found that OPLEV does all calculation  in a C code /opt/rtcds/userapps/release/aos/common/src/OPLEV.c, and in this code PIT and YAW are calculated by

pitch = (UL + UR - LR - LL)/(sum*linearResponse*leverArm);
 yaw   = (UR + LR - UL - LL)/(sum*linearResponse*leverArm);

linnear Response and leverArm are EPICS channels H2:SUS-ETMY_L3_OPLEVINF_LINRESP and H2:SUS-ETMY_L3_OPLEVINF_LEVERARM. These used to be 1, but in yesterday's terrible burt restore these were set to zero,  therefore both pitch and yaw were calculated as NaN or something, and depending on what number you multiply that would be displayed as 0 or 1e20, or something like that.

I set these two parameters to 1 and the OPLEV error signal started working.

See the attached.

Watchdog is supposed to watch SUM, PIT and YAW of the optical lever, but as of now OPLEV laser power is connected to the YAW input of the watchdog. Please fix it.

It appears that the RFM loop on the managed hub (VMIC 5595) is in the opposite way to which we imagined, from the higher numbered port down to the lower numbered port. Because we put the loop together "backwards" it turned out that for the IOP watchdog on the SUS ETMY frontend to communicate with the SEI BSC6 front end less than a foot away phyiscally, it had to run through 8km of fiber because we extended the loop to the LVEA on Tuesday this week. To run through 8km of fiber optics cable takes about 40uS. The IOP runs at 64KHz, with a processing loop taking about 15uS. So not surprisingly the SEI BSC6 IPC receiver was giving 65538 error per second.

The EY ISC was also going through 8km of fiber to communicate with SUS ETMY. This system runs at 16KHz and has 60uS loop time. 40uS could have been just sufficient, and indeed I did see a non-zero communication error rate, at about 1 error per minute.

I reconfigured the RFM loop at EY to the following

[ISC EY] -> [SUS ETMY] -> [SEI BSC6] -> [LVEA SUS ITMY] -> back to ISC EY

Now the EY IOP watchdog error rate is zero. I'll trend the ISC EY -> SUS ETMY to check it is now truely zero, but I watched it for several minutes last night and it was zero.

I am running some TFs on MC2.  This is noted for other tester staff.  Everyone else should continue work as normal in the LVEA.

Vincent left the ISIs on with their new isolation loops tonigiht.  Their performace is noticably better than a few days ago at 1Hz, and the lock is quite stable.  The attached plot shows 3 spectra: green is with the BSC8 ISI tripped, blue with both ISIs running their isolation loops, and red with some more SUS damping (the SUS settings suffered a setback after recent changes to the models).

Dave B., Jeff G.

The Simulink models for H2 SUS ITMY and ETMY were modified today to add the RFM capabilities between the Corner and End-Y stations.  Both models 'h2susitmy.mdl" and "h2susetmy.mdl" been compiled and installed on the frontends 'h2susb478' and 'h2susb6', respectively.  The top level of each custom model needed the inputs re-connected to the common "QUAD_MASTER" library part.  There were six additional inputs added to the "QUAD_MASTER.adl" inputs and three outputs, which were terminated from the top level.  The changes to the top level were also intended to facilitate the use of the newly-installed IPC card on 'h2susb6'. 

Changes saved and committed to the SVN under:
'~/userapps/sus/h2/models/'  as  "h2susitmy.mdl" & "h2susetmy.mdl"

Alberto, Keita and I finalised the WFS beam paths. The beam sizes are ~3-4mm in diameter on each of the WFS, with a picomotor mirror mount as the last optic/mirror before the WFS.

The beams are 'mostly' centered on the WFS. I haven't measured any power levels.

We placed a R=100mm (focal length ~200mm) lens infront of the RF LSC diode. This inturn seems to work properly, and there are no gain fluctuations in the CM PDH transfer function (as was the case with the previous attempt, although it tunred out that we could not work out the focal length of the other lens).

The CM PDH lock is ~12 kHz with -14dB of gain at the input. We may want to shift this gain down the path somehow.

The RF LSC diode gives ~29 mV DC.

It is a long way from being robust, and it is quite slow, but the cavity dither alignment worked this evening.  The commands are:

YAW
./tdsdither 1.9 30 4 0 300 H2:SUS-ITMY_M0_TEST_Y_EXC H2:ISC-ALS_EY_REFL_PWR_MON_OUT H2:SUS-ITMY_M0_OFFSET_Y 10 5
./tdsdither 2.3 50 5 0 300 H2:SUS-ETMY_M0_TEST_Y_EXC H2:ISC-ALS_EY_REFL_PWR_MON_OUT H2:SUS-ETMY_M0_OFFSET_Y 10 5

PIT
./tdsdither 1.9 30 4 90 300 H2:SUS-ITMY_M0_TEST_P_EXC H2:ISC-ALS_EY_REFL_PWR_MON_OUT H2:SUS-ITMY_M0_OFFSET_P 10 5
./tdsdither 2.3 50 5 30 300 H2:SUS-ETMY_M0_TEST_P_EXC H2:ISC-ALS_EY_REFL_PWR_MON_OUT H2:SUS-ETMY_M0_OFFSET_P -10 5
 

The new tdsdither is a perl script replacement for the malfunctioning ezcademod which currently lives in userapps/trunk/isc/common/scripts.  The attached image shows the power increase as the ITM and ETM alignment are dithered.

After a lot of work from Dave and the Jeffs, we got the SUSs running again.  Keita and Bram also finished revamping the ALS WFS telescopes, so there is now beam on ETMY and some power in the cavity.  It should be ready for Hartman work in the morning.

Attached are plots of dust counts > .5 microns in particles per cubic foot.

I measured the TMS ISC table angular and lateral stability when the end station VEA was quiet last night.

I found the table displacement to be around 5-10 um rms laterally and 1-3 urad rms in angle over 100s. The motion thus appears to be within the requirements: 100 um and 1 urad, respectively.