Note safety instructions
Take note of the
safety instruc-
tions for Ex ap-
plications
Voltage supply
Connection cable
Connection ca-
ble for Ex appli-
cations
LEVEL SWITCH 8112 • with transistor output
5 Connecting to power supply
5.1 Preparing the connection
Always keep in mind the following safety instructions:
Connect only in the complete absence of line voltage
l
In hazardous areas you must take note of the respective regulations,
conformity and type approval certificates of the sensors and power
supply units.
Connect the operating voltage according to the following diagrams.
Take note of the general installation regulations. As a rule, connect
LEVEL SWITCH 8112 to vessel ground (PA), or in case of plastic
vessels, to the next ground potential. On the side of the instrument
housing there is a ground terminal between the cable entries. This
connection serves to drain off electrostatic charges. In Ex applications,
the installation regulations for hazardous areas must be given priority.
The data for power supply are specified in chapter "Technical data".
The instrument is connected with standard two-wire cable without
screen. If electromagnetic interference is expected which is above the
test values of EN 61326 for industrial areas, screened cable should be
used.
Use cable with round cross-section. A cable outer diameter of 5 ... 9 mm
(0.2 ... 0.35 in) ensures the seal effect of the cable gland. If you are
using cable with a different diameter or cross-section, exchange the
seal or use a suitable cable gland.
In hazardous areas, only use approved cable connections for LEVEL
SWITCH 8112.
Take note of the corresponding installation regulations for Ex
applications.
Cover all housing openings conforming to standard according to
EN 60079-1.
5.2 Connection procedure
With Ex instruments, the housing cover may only be opened if there is
no explosive atmosphere present.
Proceed as follows:
1
Unscrew the housing cover
2
Loosen compression nut of the cable entry
3
Remove approx. 10 cm (4 in) of the cable mantle, strip approx.
1 cm (0.4 in) of insulation from the ends of the individual wires
4
Insert the cable into the sensor through the cable entry
5 Connecting to power supply
17