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Entry  Fri Jan 4 19:17:00 2019, anchal, Summary, TempCtrl, Vacuum Can Temperature Sensors (AD590) transimpedance amplifier board test - RESULTS VacCanTemSensorTest_Time_Series_Data_1229716818_to_1229904318.pdfVCTemperatureSensorsTest.zip
    Reply  Thu Jan 17 11:55:12 2019, anchal, Summary, TempCtrl, Vacuum Can Temperature Sensors (AD590) transimpedance amplifier board noise test Vacuum_Can_Temperature_Sensor_Transimpedance_Circuit_Noise_Analysis.pdfVCTMPSNS_Noise.zip
Message ID: 2274     Entry time: Fri Jan 4 19:17:00 2019     Reply to this: 2285
Author: anchal 
Type: Summary 
Category: TempCtrl 
Subject: Vacuum Can Temperature Sensors (AD590) transimpedance amplifier board test - RESULTS 

Over the break, the test of Vacuum Can Temperature Sensors transimpedance circuit was running and fb4 has logged the values. PFA time series data from fb4. See PSL:2270 for experiment details.

To reiterate:

  • Channel 0 and 1 are from the same board (Circuit 1) which is enclosed inside an aluminum box which is sitting inside a thermacol box. So this circuit should be well insulated from environmental fluctuations
  • Channel 2 and 3 are on another board (Circuit 2) which is in the open.

As seen in timeseries data, something is wrong in Ch2 data as it is fluctuating too much arbitrarily. I'll see what went worng in this particular circuit. Thankfully, I had an extra circuit on same board which is recorded in channel 3 so that we can compare the channels.


  • In terms of fluctuations over small periods, it seems both circuits perform similarly with no noticeable drift.
  • The EPICs channels are updating at 10 Hz while I found that fb4 records channels at 16 Hz. Due to this, I think we can not really do fft properly.
  • Standard deviation of a 1minute time series data for the three channels came out to be, Ch0 -> 22.5 mV , Ch1 -> 18.0 mV and Ch3 -> 15.0 mV
  • The boards are designed to have a response of 1.625 mV/mK. So either temperature is fluctuating by around 20-30 mK or the boards are 20 times worse than the design.
  • Also, clearly the offsets of each board are very different. This could be because of the difference in thin film resistor values at the adder stage or reference voltage chips.
  • There are visible offset jumps in the time series data. I'm not sure this is due to any gap in the recording which fb4 didn't understand or something actually happened. But these are periodic themselves with a period of about 2 hrs.
  • Since fb4 is running again properly now, I'll check back timeseries data of tonight.
  • Next, I'll try to make some controlled heating environment and a precise temperature sensor so that we can see if different AD590s have different slopes for temperature changes.

Edit: Fri Jan 11 11:24:11 2019

Added lighter plots. The plots now have mean value (averaged over 1 minute of data) with the shaded region showing one sigma uncertainty region. I've added the jupyter notebook in .zip file.

Attachment 1: VacCanTemSensorTest_Time_Series_Data_1229716818_to_1229904318.pdf  640 kB  Uploaded Fri Jan 11 11:25:47 2019  | Hide | Hide all
VacCanTemSensorTest_Time_Series_Data_1229716818_to_1229904318.pdf VacCanTemSensorTest_Time_Series_Data_1229716818_to_1229904318.pdf VacCanTemSensorTest_Time_Series_Data_1229716818_to_1229904318.pdf VacCanTemSensorTest_Time_Series_Data_1229716818_to_1229904318.pdf VacCanTemSensorTest_Time_Series_Data_1229716818_to_1229904318.pdf
Attachment 2: VCTemperatureSensorsTest.zip  500 kB  Uploaded Fri Jan 11 11:26:20 2019
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