Electrical connection
Leuze electronic
CML 720i Ex
48
7
Electrical connection
7.1
Shielding and line lengths
The light curtains are equipped with modern electronics developed for industrial applications. In industrial
environments, a number of sources of interference may affect the light curtains.
In the following, information is provided on the EMC-compliant wiring of the light curtains and the other
components in the switch cabinet.
7.1.1 Shielding
WARNING
Safe use of the sensor in potentially explosive areas!
Observe the information on the safe use of sensors in potentially explosive areas; see chapter 2.5.
NOTICE
General shielding information!
Avoid interference emissions when using power components (frequency inverters, …).
The necessary specifications under which the power component satisfies its CE Declaration of
Conformity can be found in the technical descriptions of the power components.
In practice, the following measures have proven effective:
Properly ground the total system.
Screw mains filter, frequency inverter, etc., flat to a galvanized mounting plate (thickness 3 mm) in the
switch cabinet.
Keep cable between mains filter and inverter as short as possible and twist cables.
Shield both ends of the motor cable.
Carefully ground all parts of the machine and of the switch cabinet using copper strips, ground rails or
grounding cables with large cross section.
Keep the length of the shieldless end of the cable as short as possible.
Guide the shielding untwisted to a terminal (no “RF braid”).
NOTICE
Separate power and control cables!
Devices with connector must be equipped with a safeguard or a mechanical interlocking guard; see
Lay the cables for the power components (mains filter, frequency inverter, …) as far from the light cur
-
tain cables as possible (distance > 30 cm).
Avoid laying power and light curtain cables parallel to one another.
Cable crossings should be laid as perpendicular as possible.
NOTICE
Lay cables close to grounded metal surfaces!
Lay the cables on grounded metal surfaces
This measure reduces interference coupling in the cables.
NOTICE
Avoid leakage currents in the cable shielding!
Carefully ground all parts of the machine.
Leakage currents arise from incorrectly implemented equipotential bonding.
You can measure leakage currents with a clip-on ammeter.
