The resistor -type temperature detector, also known as RTD or resistance thermometer, is a temperature sensor. RTD includes sensing elements, connecting sensor elements to the wires of the measuring instrument, and brackets used to locate sensor elements in this process.

 

 

The design of the RTD temperature sensor to ensure accurate and repeated temperature and resistance characteristics. The type of material for the RTD temperature sensor structure will determine the temperature limit that the RTD temperature sensor can be exposed to. The sensor element in the RTD temperature sensor is a resistor that changes the resistance value with the change of temperature. The resistance occurs with a predictable rate with changes in temperature, and can provide the temperature of the processing material by measuring.

 

The sensor element in the resistance temperature sensor usually contains a coil or a substrate with a platinum film. The allowable resistance to the extension line connected to the sending element is measured at the distance from the measured process or material. A protective cover (usually stainless steel) is equipped with sensor elements. Platinum is a typical material choice in a thermal resistance, because it allows a larger temperature range, it is a more stable material. If a lower temperature range is required, nickel and copper can also be used for RTD temperature sensor structure.

Table I. The temperature range of the summary is each material.

Table 1: Sensitive element materials and temperature limit
Material	Available temperature range
Platinum	- 200 degrees Celsius to 850 degrees
Nickel	- 100 degrees Celsius to 315 degrees
Copper	Joint 75 degrees to 150 degrees Celsius

There are two most commonly used methods for RTD temperature sensor structure. The most common is to put RTD components and connecting wires into a closed metal tube. The tube is equipped with vibration reduction and/or heat transfer materials. In most cases, alumina powder is used, and the opening of the mouth of silicon resin, epoxy resin or ceramic cement is used.
 
Another construction method is to use the mineral insulation metal sheath (MIMS) cable. RTD components insert a drilling hole and connect to the nickel or copper wires that are connected to the magnesium oxide (MGO) insulation. The end is also closed with magnesium oxide insulation and welding. The other end is sealed before the extension line connection. Once the temperature range and application are determined, Wilian will choose the most suitable material and method to build the thermal resistance temperature sensor.