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Message ID: 2270     Entry time: Tue Dec 25 11:45:15 2018
Author: anchal 
Type: DailyProgress 
Category: TempCtrl 
Subject: Vacuum Can Temperature Sensors (AD590) transimpedance amplifier board test 

Yesterday, I put two boards of LIGO-D1800304 with two pairs of circuits populated in each of them for testing.

Circuit 1:

  • Installed inside an aluminum box and shielded with thermacol to keep it safe from external temperature fluctuations as much as possible.
  • Driven by externally regulated 15V power supply.
  • Channels C3:PSL-VCTMPSNS_0 and C3:PSL-VCTMPSNS_1 carry output signals from these boards


Circuit 2:

  • Kept open to the environment to see how much environmental fluctuations would affect the readings with respect to Circuit 1.
  • Driven by externally regulated 15V power supply.
  • Channels C3:PSL-VCTMPSNS_2 and C3:PSL-VCTMPSNS_13 carry output signals from these boards



  • All four AD590 sensors are taped next to each other near the center of a large copper block with aluminum tape.
  • The power regulator of the above circuits is also taped to one end of this copper block away from sensors using kapton tape.
  • The power regulators are inside here to increase the temperature of the block to bring it within the sensing range of transimpedance amplifier boards (26 ^\circ C to 44 ^\circ C roughly).


As of today, I see that all sensors have reached a temperature which is within the sensing range of boards. However, I see different readings on them, probably due to different actual resistor value on each copy of circuit. The channels are being saved by fb4. I'll pull out time series data after some more time when we can safely assume that everything has thermalized. The fluctuations in the difference of these signals would tell us about environmental coupling and the board noise and precision itself.

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