Suitable Sensors
Note on suitable sensors:
The sensor determines the accuracy, stability, hysteresis and long-term stability of the measuring chain consisting of sensor and digital connector. For the sensor, the following must be taken into account:
- The type of Pt100 sensor element determines, among other things, the achievable measurement uncertainty / stability.
- The design (sensor diameter, installation of the sensor element, powdered or with thermal paste) influences the self heating and the hysteresis for the measurement uncertainty.
The self-heating must be included in the measurement uncertainty: If the self-heating is NOT known for the sensor design at hand, a lump sum must be charged.
Example: For a sufficiently long sheath element, an amount of 17 mK is recommended. In comparison: For the Ahlborn precision probe FPA923/FPD723 the self-heating was determined and is included in the measurement uncertainty with typ. 2 mK. The hysteresis must be described in addition to the measurement uncertainty:
If the hysteresis is not determined, a lump sum of up to 0.2 % of the span is recommended in international regulations.
Example: Calibration range 0 to 400 °C, hysteresis lump sum up to 0.8 K or calibration range 0 to 100 °C up to 0.2 K (200 mK).
