Are you interested in learning more about the working principle of the Pt100 Sensor? Well, this guide is for you. Nowadays, sensors have become a crucial component of industrial processes that maintain accurate and repeatable temperature measurements. An essential piece of equipment you can use to measure that is the Resistance Temperature Detector (RDT).
An RTD built around a resistance, the Pt100 sensor measures temperature changes. An RTD sensor is built to withstand high-vibration applications and a wide temperature range used in the refining, power, and energy industries. Besides, RTD sensors are also widely used in water baths, ovens, incubators, freezers, and humidity chambers, among other machines. Continue reading this article as we inform you more about the principle of the Pt100 sensor.
What Are Pt100 Temperature Sensors?
The platinum 100 sensor, also known as the Pt100 sensor, is one of the types of resistance thermometer. Usually, RTD sensors made of platinum wire are known as Platinum Resistance thermometers (PRT).
There are several platinum PRT/RTD sensors, such as Pt 25, Pt100, Pt 200, Pt500, and Pt100, which differ in terms of resistance. Pt100or is one of the most commonly used platinum resistance temperature detectors in the processing industry.
It uses highly pure platinum with high resistance as its sensor element. When the temperature of the object into which they are inserted changes even slightly, the resistance of the sensor will change as well. For instance, if the temperature increases, the resistance of the PTT100 sensor increases proportionally. Therefore, you can tell the temperature when you measure the resistance of the resistance temperature detector.
Although there is a wide range of RTD elements that are useful in manufacturing RTD sensors, platinum wire is the most common, and for the right reasons. It has a positive temperature coefficient. Also, the platinum RTD element has long-term stability and linearity, which makes it suitable for industrial applications because it provides exemplary accuracy. Balco wire, nickel wire, copper wire, and other metals are also used as RTD sensors.
Pt100 Sensor Working Principle
The Pt100 sensor working principle is relatively straightforward. It operates on the principle of the temperature coefficient. Usually, all types of metal have a resistivity factor as the temperature of the metal increases. Therefore, metal resistance measurements can be used to provide temperature readings.
Usually, the Pt100 sensor has a nominal resistance of 100 ohms at 0 °C and 138.5 ohms at 100 °C. The resistance value of electrical resistance is usually expressed in ohms. Furthermore, the relation between resistance and temperature is generally linear and repeatable. However, it is crucial to linearize the resistance measurement for accuracy in temperature range reading.
With PTP100 sensors, a 1°C°C temperature rise will result in a 0.385-ohm resistance value. That means even the slightest error in resistance measurement can result in enormous errors in temperature readings.
The PT100 sensors use a four-wire connection with low lead resistance for precision work. The 4-wire connection is more accurate since lead wire resistance has less impact on its accuracy.
There are other types of real-time devices, including two and three-dimensional devices. The two-wire RTD has a simple circuit design and consists of two lead wires. However, it is prone to serious lead resistance errors, which cause inaccurate data readings. While three-wire RTDs have three lead wires and are the most popular connection type in a standard bridge circuit.
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