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Entry  Thu Mar 21 16:56:42 2024, Tyler, Update, DAQ, RTD Parameter Calibration RTD_Calib-2.pngIMG_8569.jpg
    Reply  Mon Mar 25 10:55:33 2024, Tyler, Update, DAQ, RTD Parameter Calibration RTD_Calib_nobeta.png
       Reply  Tue Mar 26 13:51:56 2024, Tyler, Update, DAQ, RTD Parameter Calibration Screenshot_2024-03-26_at_1.23.27_PM.png
       Reply  Mon Jul 29 13:39:16 2024, Tyler, Update, DAQ, RTD Parameter Calibration RTD_Recal_params.pngRTD_recal_plots_fin.png
Message ID: 416     Entry time: Mon Jul 29 13:39:16 2024     In reply to: 354
Author: Tyler 
Type: Update 
Category: DAQ 
Subject: RTD Parameter Calibration 
[Tyler]

Using the data taken during the FROSTI testing at Caltech, I attempted to find a better calibration of the RTD sensors, given our past issues with inaccurate readings. The fit parameters, alpha and beta, are still all different from the initial values given to us by Fralock (alpha = .003, beta = 1.003e-6, R_0 was not given), but the true values will differ based on factors such as part geometry.

Quote:
Refitted RTD calibration, neglecting quadratic term:

       R_0 (ohm)   Alpha (1/C)

RTD 0   79.3962   0.002031

RTD 1   78.2874   0.002530

RTD 2   80.9775   0.002381

RTD 3   74.2947   0.003684

RTD 4   80.3199   0.002157

RTD 5   78.2106   0.002297

RTD 6   76.6825   0.002438

RTD 7   82.6645   0.002458


Measurements taken can be found here. An uncertainty of 1 C was assumed for temperature.

Quote:
[Jon,Tyler]

We noticed that the RTD temperature readings given on the Cymac were off, and traced the issue to miscalibration in the relationship between the resistance and temperature of each RTD (Callendar-Van Dusen eqn). Below is the table of values inferred from independent measurements of temperature and resistance to rectify this problem. This data was then fitted to better determine the coefficients present in the temperature-resistance relation:

       R_0 (ohm)   Alpha    Beta

RTD 0   80.8674   0.001315   4.273e-6

RTD 1   79.5704   0.001887   3.7873e-6

RTD 2   81.7334   0.002014   2.1724e-6

RTD 3   74.3060   0.003677   3.6022e-8

RTD 4   81.1350   0.001761   2.3598e-6

RTD 5   77.9610   0.002423   -7.5192e-7

RTD 6   78.7980   0.001373   6.2909e-6

RTD 7   83.8616   0.001890   3.3529e-6

 

 

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RTD_Recal_params.png
Attachment 2: RTD_recal_plots_fin.png  394 kB  | Hide | Hide all
RTD_recal_plots_fin.png
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