Temperature compensation is the counteracting or correction of undesirable temperature influences. This concept is very important in the manufacture of precision components and many electronic components and assemblies.
There are two forms of temperature compensation:
Active temperature compensation provides the most accurate results and is the most commonly used method.
Digital pressure sensors use electronic circuits that provide an analogue output signal proportional to the input pressure. There are three temperature-dependent factors in the sensor circuit: the zero pressure output voltage, the pressure sensitivity range and the bridge resistance. Temperature-compensated sensors are equipped with a number of correction techniques and minimise the effects of temperature fluctuations on these factors.
Thermocouplesare one of the most commonly used temperature measuring devices due to their robustness, repeatability of measurements and fast response time. However, if you do not perform cold junction compensation in the thermocouple circuit, the temperature measurement will be inaccurate.
Cold junction compensation is the process of adding (or subtracting) a voltage to the output voltage of the thermocouple to give the impression that the weld is at 0 °C. In reality, it has a different temperature because the cold end is not in an ice bath.
A small junction box can be used with a temperature controller that always keeps it at a specific temperature. If the temperature at which the reference junction is located and the type of thermocouple are known, the temperature can be calculated and compensated.
The measuring device (in the form of a transducer, a DCS input card or a temperature calibrator) can continuously measure the reference point temperature and automatically perform online compensation for this error.
A 3-wire connection is used to compensate for the temperature and resistance of the cables. As a precautionary measure, when using a 3-wire system, the connection wires should be of the same type, length and cross-section in order to compensate for the effects of the individual connection wires.
The deviation between the temperature measured by the sensor and the actual temperature depends on the altitude at which the air conditioning unit is installed. This error is compensated for by changing the jumper connection on the control board.
Tensometers are used to measure strain. Temperature compensation of the strain gauge is necessary to reduce the influence of temperature on the measurement results. The main reasons for introducing thermal compensation in strain gauges are: