Practice for Calibration and Use of Thermocouple Reference Junction Probes in Evaluation of Electronic Reference Junction Compensation Circuits

10.1520/e2730 ◽  
2015 ◽  
Author(s):  
Keyword(s):  
Reference Junction

Effect of Additional Reference Current in a Reference Junction-Double Relaxation Oscillation SQUID (RJ-DROS)

2007 ◽  
Vol 17 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Jin-Mok Kim ◽  
Yong-Ho Lee ◽  
Hyukchan Kwon ◽  
Kiwoong Kim ◽  
Ichiro Sasada
Keyword(s):  
Relaxation Oscillation ◽  
Additional Reference ◽  
Reference Junction

scholarly journals Modified Thermocouple Sensor and External Reference Junction Enhance Accuracy in Indoor Air Temperature Measurements

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6577
Author(s):  
Hans Lundström ◽  
Magnus Mattsson
Keyword(s):  
Air Temperature ◽  
Indoor Air ◽  
Measurement Errors ◽  
Room Temperature ◽  
Temperature Measurements ◽  
Indoor Climate ◽  
Internal Reference ◽  
Indoor Temperature ◽  
External Reference ◽  
Reference Junction

Indoor air temperature belongs to the most important climatic variables in indoor climate research, affecting thermal comfort, energy balance, and air movement in buildings. This paper focuses on measurement errors when using thermocouples in indoor temperature measurements, with special attention on measurements of air temperature. We briefly discuss errors in thermocouple measurements, noting that, for temperatures restricted to indoor temperature ranges, a thermocouple Type T performs much better than stated in “standards”. When thermocouples are described in the literature, industrial applications are primarily considered, involving temperatures up to several hundred degrees and with moderate demands on accuracy. In indoor applications, the temperature difference between the measuring and the reference junction is often only a few degrees. Thus, the error contribution from the thermocouple itself is almost immeasurable, while the dominant error source is in the internal reference temperature compensation in the measuring instrument. It was shown that using an external reference junction can decrease the measurement error substantially (i.e., down to a few hundredths of a degree) in room temperature measurements. One example of how such a device may be assembled is provided. A special application of room temperature measurements involves measuring indoor air temperature. Here, errors, due to radiation influence on the sensor from surrounding surfaces, were surprisingly high. The means to estimate the radiative influence on typical thermocouples are presented, along with suggestions for modification of thermocouple sensors to lower the radiation impact and thereby improve the measurement accuracy.

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