WIKA TR10-B - Handbuch (Seite 9)

WIKA operating instructions resistance thermometers per EN 14597
3132465.01 07/2011 GB/D
9
GB
3. Specifications
3.1 Resistance thermometer
Sensor connection method
■ 2-wire The lead resistance is recorded as an error in the measurement.
■ 3-wire With a cable length of approx. 30 m or longer, measuring errors can occur.
■ 4-wire The internal lead resistance of the connecting wires is negligible.
Sensor tolerance value per DIN EN 60751
■ Class B
■ Class A
■ Class AA
The combinations of a 2-wire connection with class A or class AA are not permissible, since
the lead resistance of the measuring insert negates the higher sensor accuracy.
Basic values and limiting errors
Basic values and limiting errors for the platinum measurement resistances are laid down in
DIN EN 60751.
The nominal value of Pt100 sensors is 100 Ω at 0 °C.
The temperature coefficient α can be stated simply to be between 0 °C and 100 °C with:
α = 3,85 ∙ 10 -3 °C -1
The relationship between temperature and electrical resistance is described by
polynomialss, which are also defined in DIN EN 60751. Moreover, this standard specifies the
basic values in °C steps in tabular form.
Class Temperature range Tolerance value in °C
Wire-wound (W) Thin-film (F)
B -196 … +600 °C -50 … +500 °C ±(0.30 + 0.0050 | t |) 1)
A -100 … +450 °C -30 … +300 °C ±(0.15 + 0.0020 | t |) 1)
AA -50 … +250 °C 0 … 150 °C ±(0.10 + 0.0017 | t |) 1)
1) | t | is the value of the temperature in °C without consideration of the sign.
Bold: Standard version
3. Specifications