PT100 THERMAL SENSOR

To accurately measure temperature, PT100 thermal sensors use a particularly sensitive platinum resistance thermometer. The high accuracy of the sensors allows them to be used without additional calibration of the measuring equipment. There is no lower limit for the measurement current for PTC sensors. The measurement current depends largely on the sensor’s operating conditions. The maximum recommended current for 100 Ohm is 1 mA; for 500 Ohm: 0.7 mA. The temperature sensors generate virtually no electrical potential (inductance: < 1 µH; capacitance: 1 to 6 pF) and have high shock and vibration resistance. They are distinguished by high stability of output signal values. Depending on temperature conditions, the resistance change after 5 years of operation at 200°C is typically less than 0.04%. Changes in climatic conditions and humidity fluctuations do not affect the measurement accuracy of the sensors. Due to the chemical stability and homogeneous structure of the material used, platinum temperature sensors are extremely stable temperature elements.

Connection:
Temperature sensors are typically driven by direct current with a standard 2-wire connection. To conserve power (battery or battery), alternating current can also be used.
Due to the simple square-law characteristic of temperature sensors and the possibility of a simple linear approximation, processing the measured signal is straightforward.

A standard 2-wire connection can sometimes lead to a loss of accuracy.
Upon customer request, 3- or 4-wire sensors are manufactured. These are recommended for use in the following cases:
- with long cables and low nominal resistance values, such as PT100, where the resistance and temperature-dependent resistance of the cable reach comparable values
​​- for temperature sensors with tight tolerances
- if significant electromagnetic interference is expected and twisted or shielded cables are used

Change in resistance of PT100 thermal sensor with respect to temperature

PTC Thermal Sensor

PTC thermistors are thermistors whose resistance varies nonlinearly with temperature. These sensors have a positive temperature coefficient (PTC). The temperature dependence of a PTC thermistor's resistance is characterized by a significant increase in resistance upon reaching a certain temperature.
PTC thermistors are standardly available with response temperatures (TNF) of 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 145°C, 150°C, 155°C, 160°C, and 170°C. Other temperatures are specified when ordering.

Plot of the dependence of the RTS sensor (TNF)

BIMETALLIC THERMODYNAMIC SENSOR

The operating principle is based on the generation of a thermoelectric force (thermoelectric power) when conductors with different chemical or physical properties are heated or cooled. A thermocouple consists of two metals welded together at one end. This end is positioned where the temperature is measured. A bimetallic temperature sensor prevents the motor from overheating by shutting it down when the motor temperature reaches its upper limit.