Specifications - WIKA TR Serie Manual De Instrucciones

2. Safety / 3. Specifications
2.4 Labelling, safety marks
Product label
Model
Measuring resistor in accordance with standard
F Thin-film resistor
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W Wire-wound resistor
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3. Specifications

3.1 Resistance thermometer
Sensor method of connection
2-wire
The lead resistance is recorded as an error in the measurement.
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3-wire
With a cable length of approx. 30 m or longer measuring deviations can occur.
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4-wire
The inner lead resistance of the connecting wires is negligible.
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Sensor tolerance value per DIN EN 60751
Class B
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Class A
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Class AA
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Combinations of 2-wire connection with class A or class AA are not allowed, because the lead
resistance of the measuring insert, over-rides the higher sensor accuracy.
Basic values and tolerance values
Basic values and tolerance values 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:
The relationship between the temperature and the electrical resistance is characterised by
polynomials, which are also defined in DIN EN 60751. Furthermore, this standard lays down the
basic values in °C stages.
WIKA operating instructions resistance thermometers, thermocouples
Thermometer
Number and type of sensor (here: 1 Pt100)
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Accuracy class (B, A, AA)
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Wiring configuration (2-, 3- or 4-wire circuit)
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Permissible operating temperature range for the sensor
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-3 -1
α = 3.85 ∙ 10 °C
GB
7