KROHNE OPTISWIRL 4070 ATEX II2G EN - Manual (Page 13)

ELECTRICAL CONNECTIONS
4
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OPTISWIRL 4070
www.krohne.com 04/2013 - 4000077105 MA OPTISWIRL4070 II2G AD R05 en
Electrical connections
4.1 General notes
The separate intrinsically safe signal circuits are electrically connected in the terminal
compartment of the converter. The separate intrinsically safe sensor circuits are connected in
the terminal compartments on the wall bracket and sensors. The circuits are designed in type of
protection "Intrinsic safety".
The connecting cables for signal circuits must be selected and connected according to prevailing
installation standards (e.g. EN 60079-14). Ensure that no residual current can form between
separate intrinsically safe signal circuits. The connecting cable for the sensor is included in
delivery.
• The connecting cables must be fixed and laid so they are sufficiently protected against
damage.
• Lay cables so as to ensure that there is sufficient distance between surfaces of the
measuring unit and the connecting cable.
• The outer diameter of the connecting cable must be within the sealing range of the cable
entry (10...14 mm / 0.4...0.55").
• Unused cable entries are to be closed (>IP67).
Ensure that the seals and cut seals are tight.
4.2 Power supply
Vortex flowmeters do not require a separate power supply. The required supply is provided via
the 4...20 mA current output.
4.3 Inputs / outputs
When connecting the vortex flowmeters, observe the following points:
• Before connecting or loosening the equipotential bonding cable, ensure there are no
differences in potential.
• All cores and shields belonging to the connecting cables that are not securely fitted to the
equipotential bonding of the hazardous area are to be carefully isolated from each other and
from ground (test voltage 500 V
eff
).
• Any existing cable shields should be connected to earth according to applicable installation
standards (EN 60079-14). A terminal connection in the terminal compartment permits a short
way earthing of the cable shields.
• Only certified intrinsically safe equipment may be connected to the intrinsically safe signal
outputs, taking into account the maximum permissible values. The signal outputs must be
connected to separate, intrinsically safe circuits.
The current output and the pulse / status output is designed for connection to a certified,
intrinsically safe circuit, protection type: intrinsic safety Ex ia IIC or Ex ib IIC.
The current output is safely separated from the pulse / status output up to a peak value of 60V
rated voltage. Both circuits are galvanically isolated from the earth.
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