Regensburg 2022 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 31: Superconducting Electronics and Cryogenics: Poster Session

TT 31.13: Poster

Thursday, September 8, 2022, 15:00–18:00, P1

Microprocessor controlled temperature measurement with Allen-Bradley-carbon- and Platinum-100-Sensors — •Jelko Seiboth and Andreas Wieck — Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum

This poster illustrates the setup of a device for the determination of temperatures between RT (294 K) and 4 K using Pt100 sensors and Allen-Bradley resistors with a RT value between 100 Ω and 1 kΩ. To measure the resistance, a Raspberry Pi with an analog-to-digital converter and upstream connected operational amplifiers is used. This combination provides a low price and easy further development.

The measurement is carried out with four-point technology, whereby, to reduce the temperature increase due to the electrical power consumed by the sensor, the supply of the Pt100 sensors is provided with constant current and that of the Allen-Bradley sensors with constant voltage. The device allows calibration for specific resistors and calculates the temperature from a polynomial fit function [1,2].

The determined value is shown on a display, recorded in a subsequently exportable file and output to a proportional connector with a voltage corresponding to the temperature. As the Raspberry Pi supports network connections via Ethernet and Wi-Fi, a remote retrieval or external database storage of the measurements may be implemented in the future. Calibration and temperature measurements were successfully taken to prove the functionality.

[1] B. Fellmuth, Guide to the Realization of the ITS-90. BIPM, 2018

[2] Star et al., J. Phys. [E] 2, 257 (1969)