4.2.4 Special precautions providing high noise immunity
Inductors controlled by your programmable controller (e.g. contactors and relays) do not
normally require additional snubber networks or suppressors as the respective modules
have been provided with the required components.
Snubber networks must only be connected to inductors when output circuits can be disa-
bled by means of additional contacts (e.g. relay contacts). In this case the integrated sup-
pressors on the module are also disabled. You can connect diodes to suppress back-
emc, varistors or RC-networks to the inductors.
Connections of DC-activated inductors
Connections of AC-activated inductors
using a diode
using a Z-diode
using a varistor
using RC-network
Every cubicle must be provided with a power outlet for the PU. These outlets must be
wired to the distribution system, which is also used to connect the neutral conductor for
the cubicle.
The cubicle illumination should consist of incandescent lights, e.g. LINESTRA-lamps.
Avoid using fluorescent lamps as these lamps can cause interference. If you can not
avoid using fluorescent lamps you should implement the steps outlined in the following
figure.
1
Fluorescent lamp
2
Screen above the lamp
3
Screened cable
4
Switch with metallic cover
5
Line filter or screened power cable
Inductors require snubber
networks
Equipotential bonding
Power outlet for PGs
Cubicle illumination
Suppression of fluores-
cent lamps in cubicles
HMI
Industrial Security and Installation guidelines
Installation guidelines > Special precautions providing high noise immunity
HB160 | TP | 62M-JJK0 | en | 23-10
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