What are Pt100, Pt500 and Pt1000 Sensors?

They are all types of RTD (Resistance Temperature Detector) sensor that are made from Platinum. The Pt100 sensor has a resistance of 100 ohms at 0°C and is by far the most common type of RTD sensor. The Pt500 sensor has a resistance of 500 ohms at 0°C and the Pt1000 has 1000 ohms resistance at 0°C. These sensors are normally fitted into some type of protective sheath or mounting to form a probe, and these are commonly referred to as PRT (Platinum Resistance Thermometer) or RTD probes.

How are the Pt100 sensors manufactured?

There are two main types of Pt100 element: wire wound and thin-film.

Wire wound elements consist of a length of fine Platinum wire coiled around a ceramic or glass core. These types of Pt100 element are typically 1 to 5mm diameter and 10 to 50mm in length. The ceramic or glass core can make them fragile and susceptible to vibration so they are normally protected inside a probe sheath for practical use.

Thin film Pt100 elements are manufactured using materials and processes similar to those employed in the manufacture of integrated circuits. A platinum film is deposited onto a ceramic substrate which is then encapsulated. This method allows for the production of small, fast response, accurate sensors.

What is the Accuracy of Pt100 Elements?

The International Standard IEC 751:1983 specifies the tolerances for industrial platinum resistance thermometer sensors. There are two main tolerances defined for Pt100 probes: Class A, with a tolerance of ±0.15°C at 0°C; and Class B, with a tolerance of ±0.3°C at 0°C. There are 2 additional accuracy classes for precision work and these are commonly referred to as "1/10 DIN" and "1/3 DIN" this means a tolerance of 1/10 or 1/3 of the Class B specification at 0°C respectively. The full Class A, B, 1/10 and 1/3 tolerances are listed in our Pt100 Accuracy Table along with details of the 2 main temperature coefficient curves available for Pt100 sensors.

RTD Terms

» RTD (Resistance Temperature Detector)

 An acronym for resistance temperature detector or device. A resistance temperature detector operates on the principle of the change in electrical resistance in wire as a function of temperature.

» RTD Element

 Sensing portion of the RTD which can be made most commonly of platinum, nickel, or copper. OMEGA features two styles of elements: wire wound and thin film.

» RTD Probe

 An assembly composed of an element, a sheath, a lead wire, and a termination or connection. The standard OMEGA® RTD probe is made with a 100 ohm platinum European curve element (alpha = 0.00385).

» Platinum RTD

 Also known as Pt RTD, Platinum RTD's are typically the most linear, stable, repeatable, and accurate of all RTD's. Platinum wire was chosen by OMEGA because it best meets the needs of precision thermometry.

» Thin Film RTD

 Thinfilm RTD's are made up of of a thin layer of a base metal embedded into a ceramic substrate and trimmed to produce the desired resistance value. OMEGA RTD's are made by depositing platinum as a film on a substrate and then encapsulating both. This method allows for the production of small, fast response, accurate sensors. Thin film elements conform to the European curve/DIN 43760 standards and the "0.1% DIN" standard tolerance.

» Class A RTD

 Highest RTD Element tolerance and accuracy, Class A (IEC-751), Alpha = 0.00385.

» Class B RTD

 Most Common RTD Element tolerance and accuracy, Class B (IEC-751), Alpha = 0.00385.

» Aplha .00385 Curve

 European Curve meets "0.1% DIN" standard tolerance and conforms to the DIN 43760 standard.

» Wire Wound

 The standard RTD elements used in OMEGA's probe assemblies are made of 99.99% pure platinum wire wound about a ceramic or glass core and hermetically sealed within a ceramic or glass capsule.