fafnir HART TORRIX, Technical Documentation Manual

Page: 13 / 44

Electrical connection Page 10/37
The intrinsically safe version of the TORRIX Ex level sensor, when installed in
a potentially explosive atmosphere, is permitted to be connected only to iso-
lation amplifiers that have been certified by a recognised inspection authority
and offer electrical outputs that meet the following conditions:
U
0
≤
30 V
I
0
≤
200 mA
P
0
≤
1 W
Further data can be found in the EC type-examination certificate (refer to the Appendix).
If the level sensor is to be used in a potentially explosive atmosphere, always
make sure that the permissible external capacitance (C
0
) and inductance (L
0
)
of the isolation amplifier are not exceeded (refer to the electrical data in the
EC type-examination certificate).
Used in an explosion-proof application, the connecting cable to the isolation amplifier must
be marked, preferably as a blue cable for intrinsically safe electric circuits.
To connect the cable, see chapter 5.4
5.3 Cable length
The maximum cable length depends on the total resistance (see chap. 5.1 / 5.2), composed
of the line resistances and the load of connected devices.
The cable (length and cross-section) must be chosen so that the supply volt-
age will not fall below the sensor-specific minimum voltage (8 V) in the
event of a maximum current consumption (21.5 mA) .
If the level sensor is to be used in a potentially explosive atmosphere, always
make sure that the permissible external capacitance (C
0
) and inductance (L
0
)
of the associated equipment are not exceeded (refer to the electrical data in
the EC-Type Examination Certificate).
Because of the voltage drop of 12 V the connection housing HPH Ex d and
the safety barrier SB1 can be used with TORRIX only at a supply voltage
higher than 20 volts.