RTD Sensors

RTD sensors—short for resistance temperature detectors—are temperature sensing devices used in both industrial and commercial environments to measure temperature accurately. An RTD temperature sensor operates based on the principle that the electrical resistance of certain metals changes with temperature. These sensors typically consist of a resistive element (commonly platinum, nickel, or copper) and insulated copper wires for signal transmission.

Known for its stability, precision, and wide operating temperature range, RTD sensors are ideal for environments where consistent and accurate temperature measurement is essential. Whether used in process automation, laboratory equipment, or HVAC systems, RTDs offer dependable thermal monitoring for a variety of applications.

How Do RTD Sensors work?

RTD sensors measure temperature by monitoring how electrical resistance changes as heat is applied to the sensing element. When an electric current passes through the RTD resistor—usually made from a metal like platinum—the resistance increases proportionally with temperature.

This change in resistance, measured in Ohms, is then converted into a temperature reading. The RTD temperature sensor is placed close to the heat source, allowing for precise detection of temperature changes. Different metals exhibit different resistance-to-temperature characteristics, making it essential to select the right RTD sensor type based on the required temperature range and accuracy.

Benefits of RTD Sensors

• High Accuracy: RTD sensors offer high measurement accuracy, making them ideal for applications where precise temperature control is critical.
• Wide Temperature Range: A resistance temperature detector delivers reliable readings across a broad temperature range. Platinum RTDs can measure temperatures from -200°C up to 600°C with consistent sensitivity.
• Excellent Stability: RTDs exhibit minimal drift over time, ensuring reliable long-term performance.
• Durability: RTD elements are encased in protective sheaths and constructed from durable metals like platinum or nickel, offering excellent resistance to corrosion, vibration, and mechanical wear.
• Repeatability: RTDs exhibit excellent repeatability—producing the same reading under identical conditions—and are trusted in critical systems where dependable temperature monitoring is essential for safety and efficiency.
• Linearity: RTD sensors' resistance changes almost linearly with temperature. This linearity simplifies signal processing and calibration, making them easier to integrate and use accurately.

Types of RTD Sensors

RTD sensors come in various types, each designed for specific performance needs and environments. The most common type is the Pt100 RTD, known for its exceptional accuracy and stability across a wide temperature range. It complies with IEC 60751 standards and is widely used in laboratory and industrial settings. The Pt1000 is a variation that offers ten times the resistance of the Pt100 at the same temperature, which can simplify circuit design.

Platinum RTDs

Platinum RTDs, especially Pt100 and Pt1000, offer high precision and a broad operating range. They are the industry standard for their exceptional accuracy, stability, and repeatability. The Pt100 sensor has a resistance of 100 ohms at 0°C, while the Pt1000 has 1000 ohms at 0°C, offering higher signal levels that can simplify circuit design and reduce noise.

Both types comply with IEC 60751 standards, ensuring consistent performance across manufacturers.

Nickel RTDs

Nickel RTDs provide good linearity over a moderate temperature range and are often used in HVAC and refrigeration systems where cost-efficiency and reasonable accuracy are required.

Wire Wound RTDs

These sensors use coiled resistance wire wrapped around a ceramic or glass core. They deliver high accuracy and are ideal for applications requiring precise, stable readings.

Thin Film RTDs

Thin film RTDs feature a thin resistive layer on a ceramic substrate. They are compact, cost-effective, and suitable for general-purpose temperature sensing where ultra-high precision is not critical.

Wiring Configurations: 2-Wire, 3-Wire, and 4-Wire RTDs

• 2-Wire RTDs: Used in simpler setups, 2-wire RTDs are the most basic but less accurate due to lead wire resistance.
• 3-Wire RTDs: The most common industrial configuration, compensating for lead resistance by using a third wire, improving measurement accuracy.
• 4-Wire RTDs: Designed for precision, 4-wire RTDs eliminate lead resistance errors and are used in critical measurement environments.

RTD Sensors vs Thermocouples

While both RTDs and thermocouples are temperature sensors, RTDs generally offer higher accuracy, better repeatability, and greater stability over time. Their construction exhibits a highly predictable resistance change with temperature, which leads to minimal signal drift over prolonged use and less frequent recalibration.

Thermocouples, however, can measure much higher temperatures and respond faster, making them suitable for certain high-temperature or rapid-response applications. Their ability to withstand extreme heat comes from various metal alloy pairings and small thermal mass, allowing for quick changes in voltage output as temperature fluctuates.

RTDs are preferred where precision and long-term reliability are paramount.

Industrial Applications of RTD Sensors

RTD sensors are widely adopted across industries due to their high accuracy, repeatability, and temperature stability.

Industrial Manufacturing

In manufacturing environments, RTD temperature sensors monitor heat-sensitive processes, machinery temperatures, and thermal conditions in real-time to ensure quality control and equipment efficiency.

HVAC Systems

RTDs are used in HVAC applications for precise control of ambient and system temperatures, improving energy efficiency and comfort in commercial and residential buildings.

Food & Beverage Processing

In the food industry, resistance temperature detectors ensure compliance with safety standards by monitoring temperatures during processing, cooking, and refrigeration.

Pharmaceutical & Medical Devices

RTD sensors support stringent temperature monitoring in cleanrooms, medical devices, and laboratory equipment, where consistent readings are critical for regulatory compliance and safety.

Automotive Industry

RTD equipment is used in engine testing, battery management systems, and thermal diagnostics to monitor and manage vehicle performance and safety.

Energy & Utilities

In power generation and utilities, RTD temperature sensors help regulate turbine operations, monitor oil temperatures, and maintain safe operating conditions across infrastructure components.

Your Trusted RTD Sensor Supplier at RS Singapore

RS is a trusted RTD sensor supplier and distributor in Singapore, offering a wide selection of RTD temperature sensors, RTD equipment, and accessories from leading brands like Jumo, Endress+Hauser, Prosensor. Customers can browse our extensive catalogue online at competitive prices, view stock availability, and access technical datasheets with ease.

In addition to RTD sensor solutions, we also stock components such as PDU, conduit pipes, and multimeter leads, making RS your one-stop destination for temperature sensing and control needs.

Order your RTD sensors and accessories online today and enjoy fast local delivery or convenient self-collection at your nearest branch. For more information on how to place your order, estimated delivery times, and service fees, please refer to our Ordering Page and Delivery Page.