Temperature Measurement Method by Infrared Radiation Pyrometer Using Chopped Broadband Radiation - Signal Conditioning and Acquisition Elements Design

Abstract

In this paper, we report the design of a signal conditioning and acquisition elements of a chopped broadband radiation pyrometer for measuring temperature in the range of 900 ⁰C to 1200 ⁰ C. We also report the selection of a suitable chopping frequency within the physical properties of the system and provided the calibration characteristics for the pyrometer. Based on the results, it was found that the designed signal conditioning circuit was able to produce an output voltage of 0.24 – 0.60 V corresponding to the temperature measuring range of the pyrometer. This was achieved through the use of a phase-sensitive detector (PSD) in the form of a lock-in amplifier in combination with a low pass filter. A suitable chopping frequency of 30 Hz was chosen for the shutter pulse so that the detector can have sufficient time to settle before the next shutter pulse transition. Finally, the result also shows that the calibration characteristic of the pyrometer presumes an approximately linear relationship.