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AdV-DAQ (Calibration)
lagabbe, bhattacharjee - 16:30 Tuesday 27 September 2022 (57204) Print this report
NE PCal Rx sphere installation

The position of the NE mirror couldn't be controlled due to the wind and sismic waves that produced too much noises. But the mirror z position is at the z=0.15 mm, the angles of the marionet are tx = -18.7 and ty = -27.6 urad. The PCal beam position on reflexion bench may be tilted by 0.1 mm maximum. (See NE_mirror_position_vs_time_6h.png for mirror position during the installation.)
 
time scedule:
7h52 -> 8h07 ADC port 6 (VPS1 port) voltage calibration with respect to voltage generator (time electronic 1048),
8h02 -> 8h41 VPS1 (WSV) installation on Rx bench,

  • 8h39, VPS1 ADC gain has been changed, to a value in W/V, computed at LHO
  • 8h50, VPS1 offset removed

8h55 -> 10h14 data taken by VPS1 (*see NE_photodiodes_VPS1sphere_vs_time_1h.png)

  • 8h55 -> 9h14 laser at 1.3 W loop closed
  • 9h15 attempt to plug VPS3 in parallel of VPS1 on voltage supplier, but the voltage received by VPS1 is no longer available
  • 9h24 removed VPS3 from the voltage supplier, control loop open
  • 9h42 -> 10h14 control loop closed again

9h58 ->10h03 ADC port 4 (VPS3) voltage calibration

10h15 VPS1 uninstalled
10h15 -> 10h52 VPS3 installation
10h52 -> 11h00 data taken by VPS3

  • 10h52, VPS3 ADC gain has been changed, to the value in W/V computed at LAPP
  • 10h54 -> 10h57 attempt to collect data from VPS3, but the cap was still on the sphere
  • 10h58 sphere cap removed, laser on with control loop closed

11h09 -> 11h18, test if VPS3 output voltage read by ADC is the same than the one read by keithley voltmeter

  • 11h09 laser off
  • 11h11 laser on with control loop open
  • 11h14 laser on with control loop closed

14h11, VPS3 offset subtraction
 
some remark / results:
 
 

  • When VPS3 is plugged in the voltage supplier, VPS1 doesn’t receive its power supply. And the data of VPS1 are wrong. So we cannot plug VPS1 and VPS3 at the same time, on the voltage supplier. It is maybe due to a problem in the cable 3 pins -> 3 bananas, See VPS1 output data from 9h15 to 9h25 utc, as an example.
  • The 12 m db9 - db9 is ~1 m too long
  • Comparison between ADC output and keithley output:

 
With laser off
                ADC (W)    keithley (V)
Rx_PD1    4.03 mW    6.6mV
With laser on (control loop open)
                ADC (W)    keithley (V)
Rx_PD1    1.202 W    1.723 V
With laser on (control loop closed)
                ADC (W)    keithley (V)
Rx_PD1    1.242 W    1.79 V

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Comments to this report:
lagabbe - 11:02 Thursday 29 September 2022 (57233) Print this report

Pictures of the Rx bench, and the rack taken during the installation.

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lagabbe - 13:44 Friday 30 September 2022 (57253) Print this report

As said in figure NE_photodiodes_VPS3sphere_vs_time_1h.png, there is a biais of 0.06 W between Rx_sphere (which is VPS3 calibrated at LAPP with respect to VPS1) and the Tx photodiodes. Whereas the biais between WSV (VPS1 calibrated at LHO) and Tx photodiodes is only ~1 mW. (NE_photodiodes_VPS1sphere_vs_time_20min.png)

With the voltages values taken with the ADC and the Keithley voltmeter taken in post , the biais between these two devices can be measured.

laser input power Keithley (V) ADC2378 (W) ADC2378 (V)
0 W 0.0066 0.00403 0.0058
1.3 W (closed loop) 1.79 1.242 1.786

The voltage value of the ADC2378 is computed by dividing the power value by the ADC gain written in the config file (1.3908 W/V)

The biais between the Keithley and the ADC2378 is only 0.2% of the value. Which is not enough to explain the biais between VPS3 and Tx photodiodes.

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