03.06
2.1 Secondary electrical conditions
2-25
© Siemens AG, 2006. All rights reserved
SINUMERIK 840D Configuring Manual NCU (PHD) – 03.06 Edition
These external devices may not be connected to the control during normal op-
eration. However, if the system cannot be operated without them, then the cable
shields must be connected at both ends. Furthermore, the external device must
be connected to the control via an equipotential bonding cable.
Definition:
Signal cables (example)
– Data cables (MPI, sensor cables, etc.)
– Binary inputs and outputs
– EMERGENCY OFF lines
Load cables (example)
– Low-voltage supply cables (230 V AC, +24 V DC etc.)
– Supply cables to contactors (primary and secondary circuit)
In order to achieve the best possible noise immunity of the complete system
(control, power module, machine), the following EMC measures must be care-
fully observed:
Signal cables and load cables must be routed at the greatest possible dis-
tance from one another.
If necessary, signal and load cables may cross one another (if possible, at
an angle of 90°), but must never be laid close or parallel to one another.
Only cables provided by the manufacturer should be used as signal cables
from and to the NCU.
Signal cables may not be routed close to strong external magnetic fields
(e.g. motors and transformers).
Pulse-carrying HC/HV cables must always be laid completely separately
from all other cables.
If signal lines cannot be routed a sufficient distance away from other cables,
they must be installed in grounded cable ducts (metal).
The clearance (interference injection area) between the following lines must
be kept to a minimum:
– Signal line and electrical circuit signal line (twisted)
– Signal line and associated equipotential bonding conductor
– Equipotential bonding conductor and PE conductor (routed together)
!
Important
For further notes on interference suppression measures and the connection of
shielded cables, please refer to
References: /EMC/ EMC Configuring Guidelines
Cable definitions
Rules for routing
cables
2 Connection Conditions
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