what is a Pt100 sensor

Contenuto Nascondere

1 what is a Pt100 sensor

1.1 Why is platinum used in Pt100 sensors?

1.2 Why does Pt100 need 3 wire?

1.3 What is the maximum temperature for a Pt100 sensor?

1.4 How To Calibrate A Pt100 Sensor?

1.5 How To Test A Pt100 Sensor?

1.6 How accurate is the Pt100 temperature sensor?

1.7 Which Is Better Pt100 Or Pt1000?

1.8 Thermocouple vs PT100

1.9 Conclusion

1.10 Related chillers

1.11 CONTATTO

Pt100 is a platinum resistance temperature sensor. Pt stands for platinum, and 100 means its resistance is 100Ω at 0℃. It senses temperature changes because platinum’s electrical resistance varies with temperature. The temperature can be calculated based on the resistance.

Why is platinum used in Pt100 sensors?

Good linearity – In the range of 0~600℃, the resistance of platinum shows a relatively stable linear relationship with temperature.

Strong stability – The chemical properties of platinum are very stable and not easy to oxidize or corrode.

Good repeatability – Even after repeated heating and cooling, it can still maintain a consistent resistance response.

International standard support – The resistance–temperature relationship of platinum is well-standardized across the industry.

Why does Pt100 need 3 wire?

Three wires include a power line and two signal lines. This is to offset the influence of lead resistance on the measurement results and improve temperature measurement accuracy.

What is the maximum temperature for a Pt100 sensor?

The operating temperature range of Pt100 depends on its structure type and packaging material. The common ones are as follows:

Sensor Type	Intervallo di temperatura
Thin-film	-50°C to +500°C
Wire-wound	-200°C to +650°C
Ceramic encapsulated (rare)	Up to +850°C

In order to balance response speed, life and cost, the temperature range of Pt100 commonly used in refrigeratori industriali is generally -50℃ to +250℃ or +300℃.

How To Calibrate A Pt100 Sensor?

The commonly used method for calibrating Pt100 sensors is multi-point curve calibration.

Multi-point curve calibration typically involves 3 to 5 stable temperature sources, such as oil baths or dry-block calibrators. Place the Pt100 to be calibrated and the standard thermometer or standard Pt100 in it at the same time. Compare the temperature difference between the two at multiple temperature points.

Plot the temperature and error value into a curve, and derive the compensation coefficient or lookup table value. Import the error correction data into PLC, DCS and other systems. And compare it with the standard source again until the error is controlled within the appropriate range.

How To Test A Pt100 Sensor?

You need to disconnect the Pt100 from the system and use a multimeter to measure the resistance between the two leads.

The resistance at room temperature (about 25℃) is about 109~111Ω, which means it is basically normal. A resistance of ∞
indicates an open circuit. The resistance is 0, which means it is short-circuited. The resistance deviation is large, which may indicate that the sensor is damaged or aged.

The easiest way is to put the Pt100 in an ice-water mixture (0℃) to see if the resistance is close to 100Ω.

Pt100 Sensor Resistance Reference Table (at ~25°C)
Measured Resistance (Ω)	Result	Descrizione
109 ~ 111 Ω	Normal	Typical resistance range at room temperature; sensor is working properly.
∞ (infinite)	Open circuit	Possible wire break, loose connection, or internal open circuit.
0 Ω or near 0 Ω	Short circuit	Possible wiring short or internal short circuit in the sensor.
Significantly out of range (e.g., 80Ω or 140Ω)	Faulty or degraded	Possibly aged, moisture-damaged, or thermally drifted; replacement or further testing recommended.

How accurate is the Pt100 temperature sensor?

Pt100 has many accuracy levels. The following are the common grades internationally:

Accuracy Class	Error at 0°C
Class A	±0.15°C
Class B	±0.3°C
1/3 DIN	±0.1°C

If the chiller uses a high-precision temperature measurement module and PID control, the Pt100 sensor can even achieve a temperature control accuracy within ± 0.05°C.

Which Is Better Pt100 Or Pt1000?

This table can help you quickly understand the difference between Pt100 and Pt1000.

PT100 vs PT1000 Comparison
Parametro	PT100	PT1000
Resistance at 0°C	100 Ω	1000 Ω
Wiring requirements	Typically requires 3 or 4 wires for accuracy	Can use 2 wires with minimal error
Noise immunity	Lower (requires careful wiring)	Higher (better signal-to-noise ratio)
Precisione	High and widely standardized	Moderate, less standardized across vendors
Cost	Lower	Higher
Response time	Fast	Slightly slower due to higher resistance
Best for	High-precision industrial and scientific applications	Simple or space-constrained systems with long cables

Thermocouple vs PT100

The working principle of thermocouples is that the temperature difference between two metals generates different voltages, and the temperature is calculated by the voltage. PT100 estimates temperature based on the relationship between resistance and temperature. PT100 has higher accuracy and better stability. Thermocouples respond faster and have a wider operating temperature range.

Conclusion

Choose LNEYA chillers for precise temperature control with multiple Pt100 sensors. Achieve ±0.02°C accuracy and meet the strictest thermal demands of your application.

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