WIKA TR12 Serie Manual De Instrucciones página 10

3. Commissioning, operation
3.4.1 Variant 1
The thermometer is fitted to a certified enclosure with "flameproof enclosure" ignition
protection type, which has a terminal block built into it. If the thermometer is marked with
II 2G Ex db IIC T1 ... T6 Gb, then it is designed for use in zone 1. If the thermometer is
EN marked with II 1/2G Ex ia IIC T1 ... T6 Ga/Gb, then it is designed for use with a thermowell
at the partition to zone 0.
▶
ATEX/IECEx Ex d case or connection head (with connection terminals, without
transmitter)
Evaluation of the resistance or the thermoelectric voltage by means of electronics outside
of the hazardous area.
Use in zone 1, marking II 2G Ex db IIC T1 ... T6 Gb
The flameproof case or the connection head is in zone 1 (or zone 2). The sensor is in
zone 1.
Use at the partition to zone 0, marking II 1/2G Ex db IIC T1 ... T6 Ga/Gb
The flameproof case or the connection head is in zone 1 (or zone 2). The sensor is within a
thermowell (min. wall thickness 1 mm) which extends into zone 0 via a process connection.
The thermometer should therefore be operated with a power-limiting circuit.
P : 2 W
max
U : 30 V
max
A power supply with Ex ia circuitry fulfills these conditions, but is not required if the limits
can be achieved through other measures. The responsibility rests with the operator.
A heating in the connection head does not occur with variant 1. However, an impermissible
heat reflux from the process which can exceed the operating temperature of the case or
the temperature class, must be prevented through suitable heat insulation or a suitably
long neck tube.
10 WIKA additional information TR12/TC12, flameproof enclosure (Ex d)