WIKA TR - Labelling and Safety Marks; Specifications; Resistance Thermometer

WIKA Operating Instructions RTDs and Thermocouples
11208287.03 06/2010 GB/D/F/E
7
GB
2.4 Labelling / safety marks
Product label
2. Safety / 3. Specications
3. Specications
3.1 Resistance thermometer
Sensor method of connection
■
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 deviations can occur.
■
4-wire
The inner lead resistance of the connecting wires is negligible.
Sensor tolerance value per DIN EN 60751
■
Class B
■
Class A
■
Class AA
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 coecient α can be stated simply to be between 0 °C and 100 °C with:
α = 3.85 ∙ 10
-3
°C
-1
Model
Measuring resistor in accordance with standard
■
F Thin-lm resistor
■
W Wire-wound resistor
Thermometer
■
Number and type of sensor (here: 1 Pt100)
■
Accuracy class (B, A, AA)
■
Wiring conguration (2-, 3- or 4-wire circuit)
■
Permissible operating temperature range for the sensor