Resistance Temperature Detectors (RTDs): An Overview
Resistance thermometers, commonly known as Resistance Temperature Detectors (RTDs), are highly accurate and reliable sensors used to measure Temperature by correlating the resistance of the RTD element with Temperature. They are widely used in applications where precision and stability are critical. Unlike thermocouples, RTDs operate based on the predictable change in electrical resistance of certain metals—most notably platinum—with Temperature.
RTDs are valued for their excellent repeatability, long-term stability, and accurate linear output over a broad Temperature range. They are commonly employed in laboratory, industrial, and commercial settings for Temperature monitoring and control, especially in processes requiring consistent and precise measurements.
Working Principle
The working principle of an RTD is rooted in the positive Temperature coefficient of electrical resistance exhibited by metals like platinum, nickel, or copper. As the Temperature increases, the resistance of the RTD element also increases in a known and repeatable manner.
An RTD element typically consists of a fine wire wrapped around a ceramic or glass core. The resistance is measured using a Wheatstone bridge or similar circuit, and the corresponding Temperature is derived based on standardized resistance-Temperature characteristics (such as the DIN EN 60751 standard for platinum RTDs).
Due to their stable and accurate behavior, RTDs are widely used where precise Temperature monitoring is essential, such as in power plants, refineries, chemical plants, and aerospace applications.
Model S8 – Manufactured by Ajmer Thermotech Pvt. Ltd.
Ajmer Thermotech Pvt. Ltd., an ISO 9001:2015 and CE certified company, manufactures and supplies the Model S8 RTD, designed in a Hex Nipple Process Style for secure and rugged Temperature sensing in industrial applications. This model offers a strong mechanical connection to process equipment, making it ideal for environments where durability and reliability are essential.
The hex nipple configuration enables direct and sealed insertion into pipelines, tanks, or process lines, providing both mechanical stability and ease of installation. It is especially effective in systems where vibration, pressure, or flow turbulence is present.
The Model S8 is constructed with precision platinum RTD elements and is available in 2-wire, 3-wire, or 4-wire formats to meet various accuracy requirements. It can be customized with different sheath diameters, immersion lengths, materials, and lead wire types. Ideal for use in chemical, petrochemical, pharmaceutical, and general industrial settings, the Model S8 offers dependable performance, quick response, and long service life in demanding process conditions.
