WIKA TR30 - Handbuch (Seite 21)

14016442.01 06/2011 GB/D
WIKA operating instructions model TR30 per ATEX 21
GB
Example for model TR30-W-A
Resistance thermometer, diameter: 6 mm
T
amb
= 40 °C
supplied power = 37.5 mW (see P
o
from transmitter)
Temperature class for T3, Instrument Category 1
Additional information
Temperature class for T3 = 200 °C
Safety factor for type-tested instruments (for T6 to T3) 1) = 5 K
Safety factor for applications of Instrument Category 1 (Zone 0) 2) = 80 %
1) EN 50014: 1997 Section 23.4.6.1
2) EN 1127-1: 1997 Section 6.4.2
To determine: max. permissible temperature in °C at the sensor tip T
M
Self-heating [in K] = 4 K
T
M
= (temperature class for T3 - safety factor for type-tested instruments) x safety factor for
applications with instrument category 1 - self-heating [in K]
T
M
= (200 °C – 5 K) x 0.8 – 4 K
T
M
= 152 °C
The permissible temperature in °C at the sensor tip (T
max
) = 152 °C
9. Safety-related instructions for Ex operation