YASKAWA CPU 013C Manual page 34

Basics and mounting
Installation guidelines
Basic rules for EMC
Isolation of conductors
34
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 protected earth conductor
system.
– Connect all inactive metal extensive and impedance-low.
– Please try not to use aluminium parts. Aluminium is easily oxidizing and is there-
fore 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 ampli-
tudes 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 impe-
dance-low with the cabinet.
– Use metallic or metallised plug cases for isolated data lines.
In special use cases you should appoint special EMC actions.
n
– 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 electrical operating sup-
plies 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 suffi-
ciently dimensioned potential compensation lines.
Electrical, magnetically and electromagnetic interference fields are weakened by means
of an isolation, one talks of absorption. Via the isolation rail, that is connected conductive
with the rack, interference currents are shunt via cable isolation to the ground. Here you
have to make sure, that the connection to the protected earth conductor is impedance-
low, because otherwise the interference currents may appear as interference cause.
When isolating cables you have to regard the following:
If possible, use only cables with isolation tangle.
n
n The hiding power of the isolation should be higher than 80%.
n Normally you should always lay the isolation of cables on both sides. Only by means
of the both-sided connection of the isolation you achieve high quality interference
suppression in the higher frequency area. Only as exception you may also lay the iso-
lation one-sided. Then you only achieve the absorption of the lower frequencies. A
one-sided isolation connection may be convenient, if:
– the conduction of a potential compensating line is not possible.
– analog signals (some mV respectively µA) are transferred.
– foil isolations (static isolations) are used.
n With data lines always use metallic or metallised plugs for serial couplings. Fix the
isolation of the data line at the plug rack. Do not lay the isolation on the PIN 1 of the
plug bar!
VIPA System SLIO
HB300 | CPU | 013-CCF0R00 | en | 16-40