The causes of thermocouple sensor drift and temperature drift and solution

Thermocouple sensor has zero drift and temperature drift, these two kinds of drift is affect the measuring accuracy of thermocouple sensor, how to solve these two kinds of drift is very important.

the thermocouple sensor element parameters in bridge road is asymmetric; Elastic element and a sensitive grid material temperature coefficient of resistance strain gage, different linear expansion coefficient, comprehensive factors such as set of bridge leads to inconsistent, resulting in overall temperature coefficient of thermocouple sensor adjacent arm after the bridge has a certain difference, when the temperature changes, the adjacent arm resistance variation is different, so that the bridge output is not balance, namely the zero drift; Thermocouple for smart linear displacement sensor, encoder, electronic scale, import displacement thermocouple sensor, float - — For the system, with the increase of time, is equivalent to the aging of the system for processing, in this way, the structure characteristics of the system is about to change, resulting in a drift. Temperature drift - — Affected by the temperature instability caused by zero. Visible, the influence of temperature is the main factor in the production of zero drift, is also the most difficult to control.

solve thermocouple sensor temperature drift generally there are two kinds of methods, hardware and software. Hardware method is appropriate constant in series and parallel bridge arm resistance method, bridge arm thermistor compensation method, bridge outside the thermistor in series, in parallel compensation method, double bridge compensation technology, triode compensation technique, etc. A software methodology is eliminated by software program migration, the method of corresponding digital output thermocouple sensor is very practical, customers can themselves by writing software to realize, or was a thermocouple sensor with digital display table can also be done by regulating digital display table. Is very convenient.

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key words: thermal resistance, thermocouple, thermal resistance, platinum resistance, PT100, PT1000, pressure thermocouple sensor, digital temperature thermocouple sensor