(Eric A., Corey G.)

This morning we addressed our Sensors.  Last week we found that the physically measured gap distance for our V3 was smaller than everyone else (it was around 0.074").  Fabrice requested we set this gap to 0.080" and then adjust the pot at the Mini-Rack thus electronically re-zeroing this Sensor to a good gap.

Before this work was done, we disconnected from Flange Feedthroughs and worked with the nice/expensive feedthroughs which were installed on our Interface board (we checked Sensor values after this swap, and there was no noticeable change, so we proceded).

We now have some teflon shims which are 0.080".  We will use these shims for checking that our gaps are at the nominal value of 0.080".  

After V3 was adjusted, went through the Testing Steps referenced in our Testing Document (i.e. T1000329).

Step 4 - Set Up Sensor Gaps
Here are the Sensor values (in counts) obtained with the locked table:  (mean / Std Dev)

V1:  -0.069  / 1.1
H1:  -0.052  / 0.8
V2:  +0.257  / 1.6
H2:  +0.334  / 0.7
V3:  +0.170  / 1.8
H3:  -0.235  / 1.0

*We did not do measurements with one Mini-rack on at a time since we've show that linking the Mini-Racks together has addressed our cross talk issue.

Step 5 - Measure the Sensor Gap
Here we were able to use our 0.080" teflon shim on all of our Sensors.  The shim was a tight fit, but it was consistent and was able to make it in the gap with no problem.  So, we'll say All of our measured Sensor Gaps are 0.080".


Step 6 Check Sensor Gaps After Release
Here are the locked/unlocked Sensor values (counts):  (LOCKED /UNLOCKED in counts)

V1:  -69 / -62
V2:  -52 / -223
V3:  257 / -540
H1:  334 / -93
H2:  170 / -782
H3:  -235 / -830

Step 7 Range of Motion Test #1
Here we had two people push up & push down on the system to its limits, and we noted Sensor (counts) & Dial Indicator values (thousandths of an inch).  We only did this for vertical motions.

SENSORS:  
V1:  20631 / -19327
V2:  18714 / -18139
V3:  19631 / -20730

DIAL INDICATORS:
A:  24 / -23
B:  24 / -24
C:  25 / -23.5
D:  24.5 / -21.5

Step 8 & 9 Position Sensor & GS13 Power Spectra
Went ahead and ran power spectra for our Capacitive Position Sensors & GS13's with the Table locked & unlocked.  This data is saved in the repository at:

/opt/svncommon/seisvn/seismic/HAM-ISI/X1/Data/unit_2/dtt/20100810_lock_unlocksensor_spectra.xml (and also saved GS13 & CPS individual files).

These files have been added & committed to the svn.


Step 11.1 - Actuator Sign
This is a fairly simple test (there's no "requirements" or pass/fail in the document for this).  Regardless, we moved collocated Actuators and their respective Sensors moved with the right sign.

Step 11.1 - Range of Motion Local Drive
Here we put in huge 30,000 count DAMP offsets and watched V & H Sensors.  Here the results (in counts):


V1 (+/-30k count offset)
V1:  20088 / -19439
V2:  -1989 / -353
V3:  -8540 / 8685

V2
V1:  -6256 / 4818
V2:  26420 / -24717
V3:  -8118 / 7165

V3
V1:  6022 / -6601
V2:  -15782 / 152001
V3:  21595 / -22703

H1
H1:  23863 / -24419
H2:  15560 / -17650
H3:  16362 / -17558

H2
H1:  17716 / -16627
H2:  23311 / -24489
H3:  17221 / -16864

H3
H1:  13668 / -13163
H2:  13626 / -13296
H3:  25018 / -25206

Step 12 Vertical Sensor Calibration

Going with +/-20k moves with the Vertical Actuators, we looked at Dial Indicators & Sensors on Dataviewer to calculate the Calibration.  We are given the ADC Sensor Calibration of 1638 counts/V.  Here are averaged values we obtained:

Dial Indicators:  38.1 mil
Sensors:  31753 counts

This yields a vertical sensitivity of:  31753 / 38.1 = 833 counts/mil

or 833 count/mil * 1/1638 V/count = 0.509 V/mil
or 2500 nm/mil * 1/833 mil/count = 30.5 nm/count

In addition to the power spectra, I've also attached part of the document which we completed today, if you wanted to see the actual numbers we wrote.  I'm leaving this with Eric, so he can continue other testing work while I have shifts in the Control Room over the next two days.