WIKA TR10-C - Handbuch (Seite 10)

14106886.01 06/2014 GB/D
10 WIKA operating instructions resistance thermometers and thermocouples, Ex n
GB
2. Safety / 3. Specifications
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. Specifications
3.1 Resistance thermometer
Sensor connection method
■ 2-wire
■ 3-wire
■ 4-wire
Sensor tolerance value per 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
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 polynomials,
which are also defined in EN 60751.