Precise temperature measurement with Pt100
Pt100 resistance thermometers are used for high-precision temperature measurement in industrial measurement technology. For the highest possible accuracy, 4-wire connection technology, low measuring currents and exact linearization in the measuring device are important for temperature measurement.
The Pt100 resistance thermometer provides an electrical signal via the measured electrical resistance, which changes depending on the temperature. If the temperature rises, the resistance also rises (RTD, Resistance Temperature Detector). At a temperature of 0 °C, the Pt100 with a precision resistor made of platinum (Pt) has a nominal resistance of 100 ohms.
Typical applications of the Pt100 for temperature measurement
The Pt100 is used for precise temperature measurements, for example in service life tests, in control loops, for product certifications in standardized temperature ranges, for temperature control, for temperature distribution measurements and for monitoring the temperature distribution in melting masses of injection moulding machines.
The accuracy of the temperature measurement
The Pt100 resistance thermometer provides very precise temperature measurement results in the temperature range from -200 to +850°C (in accordance with DIN EN 60751). In conjunction with a Loggito measuring device the Pt100 achieves an accuracy of 0.1 K with a 4-wire connection. In comparison: measurements with a thermocouple achieve an accuracy of 1.5 K.
One technical challenge is deviating measurement results due to the line resistance of the cables used. This is compensated for by the use of a 4-pole connection cable. Two wires are used for temperature measurement. The size of the line loss up to the sensor is determined via the other two wires and calculated by the measuring device. An alternative is the Pt1000 resistance thermometer, where the influence of the supply line is reduced by a factor of 10 due to the high nominal resistance of 1000 Ohm (at 0 °C).
Temperature measurement recording for Pt100
The Pt100 sensor is set up in a configuration dialog by simply clicking on the sensor type. The configuration and linearization are implemented automatically. The measurement results are displayed by the Delphin software ProfiSignal 20 visualized. All common diagrams are available, such as Y(t) and Y(x) trend diagrams for the temperature curve and for displaying historical measurement data from measurement databases and measurement files.