WIKA TC12-M - Handbuch (Seite 30)

GB
8. Safety-related instructions ... / 9. Calculation examples ...
14083458.01 09/2013 GB/D
WIKA operating instructions models TR12, TC12 (Ex i) 30
8.3 Variant 3:
ATEX/IECEx Ex i certified temperature transmitters.
The evaluation is carried out over a current (4 … 20 mA), voltage (0 … 10 V) or field bus
signal, which is generated from an ATEX/IECEx Ex i certified temperature transmitter.
Use in zone 1, marking II 2G Ex ia IIC Gb
The housing or the connection head is in zone 1 (or zone 2). The sensor is located in
zone 1.
The main marking for models TR12-B and TC12-B are found on the certified connection
housing or Ex i field transmitter.
The TR12-M and TC12-M modules are marked through a foil plate on the neck tube.
For a possible use at the partition to zone 0 with a thermowell, the approvals and conditions
of the relevant Ex i field transmitters must be followed.
Temperature class classification, ambient temperatures
For the measuring insert with neck tube, the following ambient temperature range applies:
(-50) 1) -40 … +85 °C
1) The value in brackets applies only for specific low-temperature designs.
The permissible ambient temperatures of the certified Ex i field transmitter must be taken
from the respective operating instructions or data sheets. Through deviations in temperature
ranges, limitations can occur.
8.4 Use in methane atmospheres
As a result of the higher Minimum Experimental Safe Gap (MESG) and Minimum Ignition
Current (MIC) of Methane, the instrument can also be used in hazardous gas atmospheres
caused by this.
U
i
= see third-party transmitter approval
I
i
= see third-party transmitter approval
P
i
= see third-party transmitter approval
L
i
= see third-party transmitter approval
C
i
= see third-party transmitter approval
9. Calculation examples for self-heating at the thermowell tip
The self-heating at the thermowell tip depends upon the sensor type (TC/RTD), the
measuring insert diameter and the thermowell design. The table below shows the possible
combinations. The heating at the sensor tip of the bare measuring insert is clearly higher;
the representation of these values was omitted on the grounds of the required assembly
with a thermowell.