In the most times it is enough to take care of some elementary rules
to guarantee the EMC. Please regard the following basic rules when
installing your PLC.
n
Take care of a correct area-wide grounding of the inactive metal
parts when installing your components.
– Install a central connection between the ground and the pro-
tected earth conductor system.
– Connect all inactive metal extensive and impedance-low.
– Please try not to use aluminium parts. Aluminium is easily oxi-
dizing and is therefore less suitable for grounding.
n
When cabling, take care of the correct line routing.
– Organize your cabling in line groups (high voltage, current
supply, signal and data lines).
– Always lay your high voltage lines and signal respectively data
lines in separate channels or bundles.
– Route the signal and data lines as near as possible beside
ground areas (e.g. suspension bars, metal rails, tin cabinet).
n
Proof the correct fixing of the lead isolation.
– Data lines must be laid isolated.
– Analog lines must be laid isolated. When transmitting signals
with small amplitudes the one sided laying of the isolation may
be favourable.
– Lay the line isolation extensively on an isolation/protected
earth conductor rail directly after the cabinet entry and fix the
isolation with cable clamps.
– Make sure that the isolation/protected earth conductor rail is
connected impedance-low with the cabinet.
– Use metallic or metallised plug cases for isolated data lines.
n
In special use cases you should appoint special EMC actions.
– Consider to wire all inductivities with erase links.
– Please consider luminescent lamps can influence signal lines.
n
Create a homogeneous reference potential and ground all elec-
trical operating supplies when possible.
– Please take care for the targeted employment of the grounding
actions. The grounding of the PLC serves for protection and
functionality activity.
– Connect installation parts and cabinets with your PLC in star
topology with the isolation/protected earth conductor system.
So you avoid ground loops.
– If there are potential differences between installation parts and
cabinets, lay sufficiently dimensioned potential compensation
lines.
5.2 EMC-equitable assembly
Mostly, measures for suppressing interference voltages are only
taken, when the control is already in commission and the perfect
receive of a wanted signal is disturbed. Causes for such interferen-
ce's are in the most cases inadequate reference potentials, coming
from mistakes at the device assembly and installation.
When assembling the devices, you have to ensure the large-surface
grounding of the inactive metal parts. A correctly done grounding sup-
ports an unambiguous reference potential for the control and reduces
the impact of coupled interferences.
Basic rules for EMC
Guidelines for assem-
bling and grounding of
inactive metal parts
VIPA HMI Panel PC
Installation guidelines
EMC-equitable assembly
HB160 | PPC | 67S-PNL0 | GB | 14-24
49
