WIKA TR12 Serie Manual De Instrucciones página 10

3. Commissioning, operation
3.1.2 Variant 2
The thermometer is built into a certified enclosure, in which an electronic assembly has
been fitted. If the thermometer is marked with II 2G Ex ia IIC T1 ... T6 Gb, then it is designed
for use in zone 1. If the thermometer is marked with II 1/2G Ex ia IIC T1 ... T6 Ga/Gb, then it
EN is designed for use with a thermowell at the partition to zone 0.
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ATEX/IECEx Ex ia case or connection head with built-in head-mounted transmitter
The evaluation is made via a current (4 ... 20 mA), voltage (0 ... 10 V) or fieldbus signal,
which is generated from a head-mounted transmitter.
Use in zone 1, marking II 2G Ex ia IIC T1 ... T6 Gb
The case or the connection head is in zone 1 (or zone 2). The sensor is located in zone 1.
Use at the partition to zone 0, marking II 1/2G Ex ia IIC T1 ... T6 Ga/Gb
The 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 be operated with a power-limiting circuit.
P : 1.5 W
max
U : 30 V
max
Powering with Ex ia electric circuit fulfills these conditions. The responsibility rests with the
operator.
A heating in the connection head can occur with variant 2 through faulty electronics. The
permissible ambient temperatures depend on the case used and any additionally fitted
head-mounted transmitter.
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, intrinsically safe designs (Ex i)