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Temperature monitoring hasn't changed much in the last decades in terms of temperature sensors, a thermal sensoring device is used to evaluate and display the current thermal conditions of a room, sample, or item . However, there are two major choices for type of sensors: thermocouples and thermistors; the latter being the most recent player joining the ranks and the more controversial when it comes to calibration.
Thermocouples had been the gold standard in temperature measuring equipment for hundreds of years, and what the majority of the people involved in the industry are familiar with. In the last decades, the thermistor technology has gained a large presence in the industry to the extent of being the dominating technology currently used. The basic concepts of thermistor operations and functionality have not spread as fast as the product itself, and are constantly confused with those of the thermocouple.
Thermocouples had been the gold standard in temperature measuring equipment for hundreds of years, and what the majority of the people involved in the industry are familiar with. In the last decades, the thermistor technology has gained a large presence in the industry to the extent of being the dominating technology currently used. The basic concepts of thermistor operations and functionality have not spread as fast as the product itself, and are constantly confused with those of the thermocouple.
Understanding the principles of resistance thermometry as they apply to thermistors will help you understand the reliability and accuracy of this type of temperature sensors and why the industry has completely shifted in this direction.
A thermistor consists of a semiconductor material whose resistance decreases as temperature increases. Key benefits of the thermistor are their small size, high accuracy and precision, and most importantly the stability of retaining its measuring characteristics for years with minimal degrading effects. Thermistors, with all these benefits, are used inside many other devices as temperature sensing and correction devices as well as in specialty temperature sensing probes for industry, science and commerce.
Thermistors are calibrated by the manufacturer by performing calculations regarding resistance/temperature characteristics and the temperature coefficient of resistance, and these conditions should not change for the life of the thermistor when used under the manufacturer's normal operating conditions, and not damaged through electrical or physical abuse.
There is a common misconception about the meaning of certain terminology used in connection with calibration. Calibration is the process of checking a given instrument against a reference with a calibration table of errors and values being generated. Any instrument can be calibrated. What consumers usually refer to is the ability to "adjust" a thermistor. When an instrument is adjusted to read in accordance with a reference instrument, Adjustment (or recalibration as it is sometimes called) is. The readout of the instrument after the adjustment is then the same as the reference instrument.
All temperature measuring devices used by Procuro, Inc. use thermistors, which have been adjusted by the manufacturer according to the set of standards or stated references of the National Institute of Standards and Technology (NIST) and other recognized international standards laboratories such as the National Physics Laboratory. Temperature calibration therefore is not required, unless it is a third party requirement to modify the adjustment for the application in which they are to be used. Manufacture's information regarding the specifications and performance data for the specific component used in all different temperature sensing modules used by Procuro, Inc. is available upon request.
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