Understanding PT100 Temperature Sensors and Their Industrial Applications
- tass peters
- Nov 20
- 3 min read
Temperature measurement plays a critical role in many industrial processes. Accurate and reliable temperature data ensures safety, quality, and efficiency. Among the various sensors available, PT100 sensors stand out for their precision and durability. These sensors use platinum resistance to provide consistent temperature readings, making them a popular choice across industries.
What Is a PT100 Sensor?
A PT100 sensor is a type of Resistance Temperature Detector (RTD) that uses platinum as its sensing element. The name PT100 comes from the fact that the sensor has a resistance of 100 ohms at 0°C. As temperature changes, the resistance of the platinum element changes in a predictable way. This relationship allows the sensor to measure temperature with high accuracy.
Platinum is chosen because it has excellent stability and repeatability over time. This means PT100 sensors maintain their accuracy even after long periods of use or exposure to harsh conditions. The sensor’s resistance increases linearly with temperature, which simplifies calibration and data interpretation.
How PT100 Sensors Work
The core principle behind PT100 sensors is the change in electrical resistance of platinum with temperature. When the temperature rises, the atoms in the platinum vibrate more, causing resistance to increase. This change is measured by passing a small current through the sensor and measuring the voltage drop.
PT100 sensors typically come with different wiring configurations:
2-wire: Simplest but less accurate due to lead wire resistance.
3-wire: Compensates for lead resistance, common in industrial use.
4-wire: Offers the highest accuracy by completely eliminating lead resistance effects.
Choosing the right wiring depends on the application’s accuracy requirements and installation constraints.
Common Formats and Installation Types
PT100 sensors are available in various physical formats to suit different environments and installation needs:
Immersion probes with stainless steel sheaths for liquids or gases.
Air probes designed to measure ambient temperature.
Screw-in sensors for machinery or pipe surfaces.
Terminal-head assemblies that simplify wiring in industrial control panels.
Ultra-low temperature versions for cryogenic applications.
The probe’s length and diameter vary depending on the installation site and required response time. For example, a thin, short probe heats up faster and provides quicker readings but may be less durable.
Industrial Applications of PT100 Sensors
PT100 sensors are widely used in industries where precise temperature monitoring is essential. Some examples include:
Food production: Ensuring correct cooking, pasteurization, and storage temperatures.
HVAC systems: Monitoring air and water temperatures for climate control.
Industrial ovens and furnaces: Maintaining consistent heat for manufacturing processes.
Compressors and refrigeration: Protecting equipment by tracking operating temperatures.
Chemical processing: Controlling reactions that depend on temperature.
Environmental monitoring: Measuring ambient conditions in labs or outdoor settings.
Their ability to maintain accuracy over time and resist electrical noise makes PT100 sensors ideal for these demanding environments.
Advantages Compared to Other Temperature Sensors
Compared with thermocouples, PT100 sensors offer several benefits:
Better accuracy over moderate temperature ranges (typically -200°C to 600°C).
Greater stability and repeatability over long periods.
Less susceptibility to electrical noise, which supports long cable runs.
Simpler calibration due to the linear resistance-temperature relationship.
While thermocouples can measure higher temperatures and respond faster, PT100 sensors are preferred when accuracy and reliability are more important.
Selecting the Right PT100 Sensor
Choosing the correct PT100 sensor involves considering several factors:
Temperature range: Ensure the sensor covers the expected operating temperatures.
Probe length and diameter: Match the installation site and response time needs.
Wiring type: Decide between 2-, 3-, or 4-wire configurations based on accuracy and wiring complexity.
Installation method: Select the appropriate probe style for immersion, surface, or air measurement.
Environmental protection: Look for sensors with suitable ratings for moisture, chemicals, or mechanical stress.
Proper selection helps avoid inaccurate readings, reduces maintenance, and extends sensor life.
Best Practices for PT100 Sensor Use
To get the most from PT100 sensors, follow these guidelines:
Use shielded cables and proper grounding to minimise electrical noise.
Calibrate sensors periodically to maintain accuracy.
Avoid mechanical stress on the probe that could damage the sensing element.
Match sensor specifications to the process requirements.
Use appropriate mounting hardware to ensure good thermal contact.
These steps improve measurement reliability and reduce downtime.
