WIKA RTD User Manual

3345267.08 06/2011 GB/D
10 WIKA operating instructions RTD and TC, intrinsically safe designs
GB
Explanation of symbols
Before mounting and commissioning the instrument, ensure you read the
operating instructions!
CE, Communauté Européenne
Instruments bearing this mark comply with the relevant European directives.
ATEX European Explosion Protection Directive
(Atmosphère = AT, explosible = EX)
Instruments bearing this mark comply with the requirements of the European
Directive 94/9/EC (ATEX) on explosion protection.
3. Specications
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 longer than approx. 30 m, measuring errors can occur.
■
4-wire The internal lead resistance of the connecting wires is negligible.
Limiting error of the sensor per DIN EN 60751
■
Class B
■
Class A
■
Class AA
The combination of a 2-wire connection with Class A / Class AA is 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 coecient 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 dened in DIN EN 60751. Moreover, this standard species the basic values in °C
steps in tabular form.
2. Safety / 3. Specications

WIKA RTD Specifications

General

Brand	WIKA
Model	RTD
Category	Measuring Instruments
Language	English