RTD Sensors

RTD sensors, also called a Pt100 sensor, offer precise temperature measurement by correlating the electrical resistance of a platinum element with temperature. This high accuracy and stability makes RTD sensors essential in industries like pharmaceuticals, food processing, and aerospace, where precise temperature control is critical for product quality and safety. Industrial RTDs are vital for monitoring critical process parameters and ensuring optimal performance in demanding environments.

What Is a RTD Sensor?

Resistance temperature detectors (RTDs) are essential components in industries where accurate and reliable temperature measurement is critical. These sensors provide precise temperature readings over a wide range, making them ideal for demanding applications in various sectors. RTDs are known for their stability, repeatability, and ability to withstand harsh environments, ensuring consistent performance and accurate temperature monitoring in critical processes.

How Does a RTD Sensor Work?

RTD sensors typically utilise insulated copper wires and a resistance element made of platinum, nickel, or nickel-iron — materials that are sought for their high accuracy and fast response time across a wide temperature range. This resistance element is situated close to the area where temperature measurement occurs.

An electrical current passes through the RTD's resistance element, causing both the temperature of the metal element and its electrical resistance to increase. This resistance value is measured in Ohms and converted into a temperature reading.

RTD Standard Tolerances

RTD sensors are manufactured to specific tolerances, which define the accuracy of their temperature measurements. These tolerances are typically expressed as a function of temperature and are categorised into different classes according to DIN standards.

Common tolerance classes include:

• DIN Class A: ±(0.15 + 0.002 |T|°C)
• DIN Class B: ±(0.3 + 0.005 |T|°C)
• DIN Class C: ±(1.2 + 0.005 |T|°C)

The tolerance class you choose should be based on the application's requirements for precision. For applications where high accuracy is critical, such as laboratory measurements or critical process control, a Class A sensor would be more suitable. For less demanding applications, where a wider tolerance is acceptable, a Class B or Class C RTD may suffice.

Types of RTD Sensors

Pt100 Sensor

The Pt100 sensor is the most widely used type of RTD sensor in industrial applications. It is constructed from platinum and has a resistance of 100 ohms at 0°C. Pt100 sensors are laboratory-grade sensors that are IEC 60751 compliant, which stands to reason why they are favoured for their accuracy, stability over a wide temperature range, and excellent linearity. They are commonly used in industrial process control, temperature monitoring, and automation systems.

Pt1000 Sensor

Pt1000 sensors are similar to Pt100 sensors in terms of construction and material but have a higher resistance of 1000 ohms at 0°C. This higher resistance can offer advantages in certain applications, such as increased sensitivity and reduced susceptibility to electrical noise.

Thin Film RTDs

Thin film RTDs are constructed by depositing a thin layer of platinum or other resistive material onto a ceramic substrate. This construction results in a compact size and fast response time, making them suitable for applications where rapid temperature changes need to be measured. Thin film RTDs are often used for surface temperature measurement and in applications where space constraints are a concern.

Wire-Wound RTDs

Wire-wound RTDs are constructed by winding a fine wire of platinum or other resistive material around a ceramic or glass core. This design offers excellent stability and accuracy, particularly at higher temperatures. Wire-wound RTDs are known for their durability and ability to withstand harsh environments, making them suitable for demanding industrial applications.

Benefits of Using RS RTD Sensors

RS Malaysia offers a wide range of high-quality RTD sensors designed to provide accurate and reliable temperature measurements in various applications.

• Accurate Temperature Measurement: RTD temp sensors offer unparalleled accuracy with tight tolerances, ensuring reliable data for critical processes where precision is paramount. This makes them ideal for applications demanding precise temperature monitoring and control.
• Wide Temperature Ranges: Whether you need to measure extremely low or high temperatures, RTD sensors operate effectively across a broad spectrum, making them suitable for diverse industrial environments, from cryogenic applications to high-temperature furnaces.
• Exceptional Durability: Built to last in challenging environments, industrial RTDs are constructed with robust materials and designs for longevity and reliable performance even in harsh conditions, minimising maintenance needs and maximising operational efficiency.
• Excellent Stability: Unlike some temperature sensors that are prone to drift, RTD sensors maintain consistent performance over time. This long-term stability ensures accuracy and reliability, making them ideal for applications requiring stable and repeatable measurements.
• High Repeatability: When it comes to consistent and reliable data, RTD sensors provide highly repeatable measurements, ensuring confidence in the data collected and enabling precise process control and analysis.

RTDs vs Thermocouples

RTD's offer several advantages over thermocouples, such as:

• Wider Measurement of Temperature: RTDs generally offer a wider temperature measurement range than thermocouples, typically covering temperatures from -200°C to 850°C.
• Higher Accuracy than Thermocouples: RTDs are known for their higher accuracy and stability, especially at lower temperatures. They exhibit less drift and provide more consistent readings over time compared to thermocouples.
• Linear Response: RTDs exhibit a more linear response to temperature changes compared to thermocouples. This linearity simplifies signal processing and calibration, making it easier to convert resistance measurements into accurate temperature readings.
• No Cold Junction Compensation: RTDs do not require cold junction compensation, a process necessary for accurate thermocouple measurements. This simplifies the measurement setup and reduces potential sources of error.

RTDs vs Thermistors

RTDs and thermistors are both temperature-sensitive resistors, but they differ in their characteristics and applications. Here is a comparison:

• Wider Temperature Range: RTDs generally have a wider operating temperature range compared to thermistors. This makes them suitable for a broader range of applications, including those with extreme temperatures. Thermistors, while highly sensitive, often have a more limited temperature range.
• Linearity: RTDs offer better linearity compared to thermistors, which typically exhibit a non-linear response to temperature changes. This linearity makes RTDs easier to calibrate and use, as the relationship between resistance and temperature is more predictable.
• Stability: RTDs are generally more stable over time and less susceptible to drift compared to thermistors. This stability ensures consistent and reliable temperature measurements over the long term.

Wiring Configuration of RTD Sensors

RTD sensors can be connected to measuring instruments using different wiring configurations, each with its own advantages and trade-offs in terms of accuracy and complexity. The most common configurations are two-, three-, and four-wire sensors, all of which provide a means of compensating errors in temperature and resistance measurement. The choice of wiring configuration depends on the application's accuracy requirements and the distance between the sensor and the measuring instrument.

How to Select a Suitable RTD Sensor

Choosing the right RTD sensor for your application involves careful consideration of several factors to ensure accurate and reliable temperature measurement. Here is a breakdown of key aspects to keep in mind:

Temperature Range

The first step is to determine the expected temperature range of your application. RTD sensors are available in various temperature ranges, typically from -200°C to 850°C. Select a sensor with a temperature range that comfortably encompasses the anticipated operating temperatures to ensure accurate measurements and prevent sensor damage.

Accuracy

The accuracy of an RTD sensor is determined by its tolerance class, as discussed earlier. Choose a sensor with a tolerance class that meets the precision requirements of your application. For high-accuracy applications, Class A RTDs are recommended, while Class B or C might be suitable for less demanding applications.

Response Time

The response time of an RTD sensor refers to the time it takes for the sensor to react to a change in temperature. This is an important consideration for applications where rapid temperature fluctuations need to be measured. Thin-film RTDs generally offer faster response times compared to wire-wound RTDs.

Physical Size and Mounting

Consider the physical size and mounting style of the RTD sensor to ensure compatibility with your application. RTDs come in various sizes and forms, including probes, surface mount devices, and industrial assemblies. Choose a sensor with a suitable form factor and mounting mechanism that fits your installation requirements.

Environmental Conditions

The environment in which the RTD sensor will be operating can significantly impact its performance and longevity. Consider factors such as ambient temperature, humidity, vibration, and exposure to chemicals or corrosive substances. Choose a sensor with appropriate protection and materials that can withstand the environmental challenges of your application.

Trusted RTD Sensors Manufacturer, Supplier and Distributor in Malaysia

RS is a trusted and leading RTD sensor manufacturer, supplier, and distributor in Malaysia. We offer a wide selection of high-quality RTD sensors at competitive prices, catering to various industrial and commercial applications. Our product range includes RTD sensors from reputable brands like Honeywell, Prosensor, and Siemens, ensuring you find the perfect solution for your temperature measurement needs.

When it comes to RTD sensor price, the cost varies depending on the type, specifications, and brand. However, RS offers competitive pricing, making us a cost-effective option for businesses seeking reliable temperature sensors without compromising on quality.

While we excel in providing high-quality RTD sensors, our commitment to offering comprehensive solutions extends beyond temperature measurement. We also offer a wide range of proximity sensors and level sensors, ensuring you can find the perfect sensing solution for your specific application, all from one reliable source.

Buy PT100 and PT1000 Sensors Online from RS

RS Components Malaysia provides a seamless online ordering experience, allowing you to easily browse our extensive range of RTD sensors, compare specifications and prices, and place your order with just a few clicks. For more information, head to our delivery page.