What is resistance temp detector?

The resistance temperature detector, or the RTD, is a sensor whose resistance changes with temperature. Typically built of a platinum (Pt) wire wrapped around a ceramic bobbin, the RTD exhibits behavior which is more accurate and more linear over wide temperature ranges than that of a thermocouple.

How an RTD is used to measure temperature?

An RTD is a temperature sensor which measures temperature using the principle that the resistance of a metal changes with temperature. In practice, an electrical current is transmitted through a piece of metal (the RTD element or resistor) located in proximity to the area where temperature is to be measured.

What is a DIN curve of RTD?

An RTD is a passive device. RTDs are built to several standardized curves and tolerances. The most common standardized curve is the ‘DIN’ curve. The curve describes the resistance vs temperature characteristics of a Platinum, 100 ohm sensor, the standardized tolerances, and the measurable temperature range.

What are the RTD materials?

Typically, RTDs contain either platinum, nickel, or copper wires, as these materials have a positive temperature coefficient. This means that a rise in temperature results in an increased resistance – this change of resistance is then used to detect and measure temperature changes.

How are resistance detectors used to measure temperature?

Resistance temperature detectors (RTDs) are based on the principle that the electrical resistance of a metal increases as temperature increases. Thus, a temperature measurement can be inferred by measuring the resistance of the RTD element.. A basic construction of an RTD is shown below:

How is a resistance thermometer or RTD used?

A Resistance Thermometer or Resistance Temperature Detector is a device which used to determine the temperature by measuring the resistance of pure electrical wire. This wire is referred to as a temperature sensor. If we want to measure temperature with high accuracy, RTD is the only one solution in industries.

What are the components of a resistance detector?

The components of Resistance Temperature Detector (RTD) are: Resistance Element is the main temperature sensing portion of the Resistance Temperature Detector. The Element’s length ranges from 1/8″ to 3″. The standard resistance is 100 Ω at 0° C and the standard temperature coefficient is an alpha of .00385.

Which is more accurate a RTD or four wire resistance detector?

Four wire Resistance Temperature Detectors are even more accurate than Three wire RTDs as they are able to completely compensate for the resistance of the wires without having to pay attention to the length of each of the wires. This provides significantly increased accuracy at low cost of increased copper extension wire.