Select the temperature sensor is more than the content of other types of sensors to be considered.
First, the structure of the sensor must be chosen so that the measurement time of the sensing element can reach the temperature of the measured fluid or the measured surface. In most cases, the choice of temperature sensor, to consider the following aspects of the problem:
(1) whether the temperature of the object being measured is recorded, the alarm and automatic control, whether it is necessary to measure and transfer.
(2) the range of temperature measurement and accuracy requirements.
(3) the size of the temperature measuring element is appropriate.
(4) in the measurement of the temperature of the object with the time of the occasion, the temperature measurement device can not meet the requirements of temperature measurement.
(5) whether the environmental conditions of the tested objects have damage to the temperature measuring elements.
The choice of temperature sensor is mainly based on the measurement range. When the measurement range is expected to be within the total range, the platinum resistance sensor can be used. The narrow range typically requires that the sensor must have a fairly high base resistance in order to obtain a large enough resistance variation. The thermistor is provided with a large enough resistance to make these sensitive elements very suitable for narrow measurement range. If the measurement range is quite large, the thermocouple is more applicable. Preferably the freezing point is also included in this range, as the thermocouple gauge is based on the temperature. The linearity of the sensor in the known range can also be used as an additional condition for selecting the sensor.
Response time is often expressed as a time constant, and it is the basic basis for selecting the sensor. The time constant is less important when the temperature in the tank is to be monitored. However, when the temperature in the vibration tube must be measured in the process of use, the time constant becomes the deciding factor of the sensor.
Dynamic temperature measurement is more complex, only through repeated testing, as close as possible to simulate the conditions that occur frequently in the use of sensors, in order to obtain a reasonable approximation of the dynamic performance of the sensor.
