IEC 60751 Industrial Platinum Resistance Thermometers and Platinum Temperature Sensors

The "IEC 60751 Industrial platinum resistance thermometers and platinum temperature sensors" standard, published by the International Electrotechnical Commission (IEC), describes requirements for industrial platinum resistance thermometers and industrial platinum resistance temperature sensors where electrical resistance is derived from defined functions of temperature, in addition to the resistance-temperature relationship.

This standard covers platinum resistors and thermometers with different tolerance classes within a temperature range of -200 degrees to +850 degrees. It may also cover specific platinum resistors or thermometers for a particular portion of this temperature range.

For resistance-temperature relationships with uncertainties less than 0,1 degrees, possible only for platinum resistors or thermometers with exceptionally high stability and individual calibration, a more complex interpolation equation than that presented in this standard may be required. The specification of such equations is outside the scope of this standard.

The nominal resistance-temperature relationship and tolerance classes for platinum resistors and thermometers are standardized. This standard applies to the connection points of a sensing platinum resistor and the terminals of a thermometer.

In two-wire connections, the resistance values ​​of the ends between the platinum resistor connection point and the terminals must be considered. These values ​​should be subtracted from the measured resistances. In some cases, it is recommended to also consider the temperature coefficient of the end wires, the geometric characteristics of the wires, and the temperature distribution along their length. This information can be provided to users as additional information.

For a thermometer to conform to this standard, it must be made of platinum resistance that meets this standard. Platinum resistances and thermometers are tested to prove that the device meets all applicable requirements specified in this standard. Suppliers are responsible for performing the tests and proving the device's conformity to this standard before delivering it to the user. The test method and evaluation are specified in this standard.

In the world of industrial temperature measurement, accuracy and reliability are paramount. This is where the IEC 60751 standard, an international standard that forms the basis for platinum resistance thermometers and sensors, comes into play. This standard defines the critical relationship between temperature and electrical resistance for industrial-grade platinum-based devices. The IEC 60751 standard ensures that these sensors deliver accurate and repeatable results under a wide range of conditions.

This latest update to the standard reflects advances in sensor technology while maintaining backward compatibility where possible.

Sensors compliant with the IEC 60751 standard are widely used in industries requiring robust temperature control. For example,

• Process automation: In refineries and food processing, Pt100 probes monitor pipelines with minimal deviation over the years.
• HVAC and building management: Provides energy-efficient climate control by accurately monitoring ambient conditions.
• Medical and laboratory equipment: Supports sterile environments with traceable accuracy.

This latest update to the standard introduces improvements to reduce the confusion created by previous changes. Key updates include:

• Seven technical changes include expanded RT functions, updated polynomial coefficients for ITS-90 alignment, and clearer definitions for sensor configurations.
• Tolerance explanations: By emphasizing full thermometer testing, it resolves the debate between element accuracy and system accuracy alone.
• Broader scope: It explicitly includes both thermometers and bare resistors, providing guidance on vibration resistance for thin-film elements.

These changes minimize errors in long cable applications where a 1Ω cable resistance could distort the Pt100 reading by 1 percent, but only by 0,1 percent for Pt1000.

The IEC 60751 standard defines the fundamental rules for ensuring accuracy, reliability, and consistency in temperature measurement. The main reasons why this standard is considered so important, especially in industrial applications, are as follows:

• It ensures sensitivity and accuracy: This standard mathematically defines the relationship (RT curve) between temperature and electrical resistance in platinum sensors. This allows measurements to be taken with millisecond accuracy in the range of -200 degrees to +850 degrees.

Tolerance classes define the maximum deviation limits of sensors. For example, a Class A sensor offers an accuracy of plus/minus 0,15 degrees, minimizing errors in critical processes from laboratories to factories.

Conclusion: It prevents production losses, energy waste, or safety risks caused by inaccurate measurements. For example, even a 1-degree deviation in a chemical reactor can create a risk of explosion.

• Global compatibility and standardization: This standard is valid worldwide. Manufacturers in different countries adhere to the same rules, ensuring equipment compatibility. It provides backward compatibility with older systems (e.g., DIN standards) but adapts to modern technologies (ITS-90 temperature scale) with the latest update. This prevents problems in the supply chain.
• Enhances industrial safety and reliability: This standard defines the sensors' resistance to vibration, humidity, and self-heating failures. It integrates with hazardous area standards, ensuring safe use in explosive environments (oil refineries).

In short, temperature measurement without the IEC 60751 standard would be chaotic and unsafe. This standard enables industries to remain efficient, safe, and competitive.

In conclusion, the IEC 60751 standard enables global interoperability in temperature measurement. By defining precise RT relationships and tolerances, it allows industries to achieve reliable and cost-effective sensing.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its customers, providing the advanced testing services they require, and assisting in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services to businesses in accordance with the "IEC 60751 Industrial platinum resistance thermometers and platinum temperature sensors" standard.