YAGEO Nexensos has introduced the M422 Pb-free platinum resistance temperature detector (Pt-RTD), extending its lead-free M-Series temperature-sensor portfolio.
The YAGEO wired sensor provides resistance-based temperature measurement across an operating range of −70 °C to +500 °C. Nominal resistance options are 100 Ω, 500 Ω and 1000 Ω, with three tolerance classes defined according to DIN EN 60751.
Key features and benefits
- Pb-free version of the M422 platinum temperature-sensor platform.
- Operating temperature range from −70 °C to +500 °C.
- Nominal resistance choices of 100 Ω, 500 Ω and 1000 Ω.
- Tolerance classes F 0.1 (1/3 B), F 0.15 (A) and F 0.3 (B), according to DIN EN 60751.
- Connection options include welding, brazing and crimping.
Technical highlights
A platinum RTD converts temperature into a change in electrical resistance. Its resistance increases with temperature and follows a standardized, nearly linear characteristic. Measurement electronics determine the sensor’s voltage drop and convert the resulting resistance measurement into a temperature value.
| Parameter | M422 Pb-free |
|---|---|
| Sensor technology | Platinum RTD |
| Operating temperature | −70 °C to +500 °C |
| Nominal resistance | 100 Ω / 500 Ω / 1000 Ω |
| Tolerance classes | F 0.1 / F 0.15 / F 0.3 |
| Tolerance standard | DIN EN 60751 |
| Joining technologies | Welding / brazing / crimping |
Tolerance class and measurement accuracy
The tolerance-class designation describes permitted deviation from the standardized platinum resistance–temperature characteristic. At 0 °C, F 0.1 corresponds to ±0.10 °C, F 0.15 to ±0.15 °C and F 0.3 to ±0.30 °C. These reference-point values are not constant error limits across the operating range.
Sensor operating range and tolerance-class validity are separate selection criteria. Match the required measurement accuracy to the applicable class over the intended temperature interval, rather than selecting from the 0 °C tolerance alone. The complete measurement chain also needs to match the sensor characteristic: sensor tolerance does not by itself define the accuracy of the finished instrument.
Resistance and tolerance selection
Nominal resistance and tolerance class address different parts of the measurement design. The resistance option must match the readout electronics, while the tolerance class forms part of the temperature-error budget.
The operating temperature range and tolerance-class designation should be treated as separate selection criteria. Choose the required accuracy over the actual measurement interval rather than treating a class label as a temperature-independent error figure.
Connection technology
Welding, brazing and crimping support different sensor-assembly processes. The selected joining method should be considered together with the mechanical arrangement and thermal exposure of the completed sensing assembly.
A lead-free sensing element is also a component-level choice. The connection materials and assembly process remain part of the finished product’s material-compliance assessment.
Typical applications
Target applications for the M422 Pb-free include:
- Pyrolytic ovens.
- Home appliances.
- Heating, ventilation and air-conditioning equipment.
- Medical devices.
- Industrial process monitoring.
For sensor-technology selection, the distinction between the positive, nearly linear response of a platinum RTD and the negative, nonlinear response of an NTC thermistor affects signal conversion and interface compatibility. The thermistor-based temperature sensing system guide provides further context on these measurement approaches.
The +500 °C upper operating limit is relevant to temperature sensing in pyrolytic ovens and elevated-temperature industrial processes. The −70 °C lower limit also accommodates measurement duties extending below freezing, including HVAC applications.
Across these markets, the three nominal resistance options allow the sensing element to be selected around the intended measurement electronics. The tolerance-class choice then addresses the sensor’s contribution to measurement accuracy.
Design-in notes for engineers
- Match the nominal resistance to the measurement front end and its resistance-to-temperature conversion.
- Select the tolerance class against the required accuracy over the application’s measurement interval.
- Keep the sensor’s local operating temperature within −70 °C to +500 °C, accounting for both normal operation and thermal excursions.
- Include the joining method in the assembly design. Welding, brazing and crimping require different tooling and connection arrangements.
- Assess the sensing element, electrical joints and mechanical installation together before production release.
- Validate the final sensor assembly under the actual operating conditions.
Further reading
- Thermistor Basics: NTC and PTC Selection Guide
- Thermistor Temperature System Optimization and Evaluation
Source
This article is based on the YAGEO Group product announcement and official product documentation. Engineers should refer to the current manufacturer datasheet for final design and qualification.
References
- YAGEO Group, M422 Pb-Free Pt-RTD.
- YAGEO Group, Product Brief: Wired Pt-RTD M-Series — M422 Pb-free, Rev. A, July 2025.
- YAGEO Group, Pt and NTC Temperature Sensors: A Comparison of their Advantages Including Accuracy, Long-Term Stability and Repeatability.
