Siemens Simovert Masterdrives Compendium page 97

Instructions for Design of Drives in Conformance with EMC Regulations
3.4.1 The zone concept
3-10
The most cost-effective measure of reducing interference is to spatially
separate the noise sources and the noise receivers. This must,
however, already be taken into account during the planning stage of a
machine/system. The first question that has to be answered is whether
the unit used is a noise source or a noise receiver. Noise sources in
this connection are, for example, frequency converters, braking units,
contactors.
Noise receivers are, for example, automation devices, encoders and
sensors.
The machine/system is then divided up into EMC zones and the units
are assigned to these zones. Each zone has its own requirements
regarding noise emission and noise immunity. The zones have to be
spatially separated, which is best done using a metal housing or, within
a cabinet, using grounded partitions. If necessary, filters have to be
used at the zone interfaces. The zone concept is explained using the
following diagram as an example which shows a simplified drive
system:
6SE7087-6QX70 (Version AD)
Compendium Motion Control
05.2003
Siemens AG
SIMOVERT MASTERDRIVES