5.2 Assembly of the components in the control cabinet
Basically, the following applies:
The effect of the interference size decreases with an increasing distance
between interference source and interference sink.
An additional decrease of the interferences can be achieved by the installation
of earthed shielding plates.
All components must be connected extensively and with good conduction to
When installing the components (assemblies, modules, circuitboards etc.), ensure
that these are firmly connected with the support bar (module assembly frame, etc.),
to ensure the correct functioning of the assembly. The recommended torque must
be observed for the fastening bolts.
Control panels with monitors
It must be ensured that no lines or devices with solenoids are arranged next to the
monitors which generate strong magnetic fields, e.g. power lines, contactors,
relays, solenoid valves, transformers, etc.
Power and control components
Power components (transformers, driving appliances, load power supply units, etc.)
should basically be arranged separately from the control components (relay control
parts, digital controls, programmable controls, e.g. SIMATIC etc.). This does not
apply, however, to power components which are provided by the manufacturer
already for the common structure (e.g. SIMODRIVE 611 and SINUMERIK 840D).
The metal housing of all components, particularly the housing of converters and the
appropriate filter modules must be connected at a low resistance to the control
cabinet for high-frequency interference currents. The modules are to be mounted
for this ideally on a conductive blank metal plate and must be connected
extensively to it. Painted control cabinet walls as well as hat bars or similar
assembly aids with a small contact surface do not meet these requirements.
SINUMERIK FM components are attached to the assembly bar of the
SIMATIC system S7-300. This assembly bar must be connected via extensive
conduction to the control cabinet.
Filter modules for converters
Filter modules are necessary for compliance with the EMC thresholds. They reduce
the coupling of device-internal interferences of the converters to the power line.
These filter modules are functionally mounted directly adjacent to the
feed/feedback module (see following figure). Optionally, assembly in direct
proximity to the control cabinet mains feed is also possible.
Filter modules from A&D are suitable only for the interference suppression of A&D
© Siemens AG, 2004. All rights reserved
EMC Installation Guideline – Planning Guide (EMV) – 03.2004 Edition
Control Cabinet Structure