Chapter 3 Installation Guidelines
Manual VIPA HMI
3-6
HB160E - TP - RE_62F-FEE0 - Rev. 12/51
EMC-equitable assembly
Mostly, measures for suppressing interference voltages are only taken,
when the control is already in commission and the perfect receive of a
wanted signal is disturbed.
Causes for such interference's are in the most cases inadequate reference
potentials, coming from mistakes at the device assembly and installation.
When assembling the devices, you have to ensure the large-surface
grounding of the inactive metal parts. A correctly done grounding supports
an unambiguous reference potential for the control and reduces the impact
of coupled interferences.
Grounding means the conducting connection of all inactive metal parts.
The sum of all interconnected inactive parts is called ground.
Inactive parts are all conductive parts electrically separated from all active
parts by means of a basic isolation and that may only get voltage in case of
an error.
The ground must not adopt dangerous contact voltage even in case of an
error. Thus you have to connect the ground with the protected earth
conductor. To avoid ground loops, local distant ground constructions
(cubicles, construction and machine parts) have to be connected with the
protected earth conductor system in star-topology.
Please regard at grounding:
•
Connect the inactive metal parts as carefully as the active ones.
•
Take care of impedance-low metal-metal-connections, e.g. with large-
surface and well conductive contacts.
•
If you include coated or anodized metal parts in the grounding, you have
to come through the isolating protection layers. For this you may use
special contact washers or remove the isolation layer.
•
Protect the connection points from corrosion, e.g. with grease.
•
Moveable grounding parts (e.g. cubicle doors) have to be connected via
flexible ground strips. The ground strips should be short and have a
large surface, because the surface is decisive for the diversion of high
frequency interferences.
Guidelines for
assembling and
grounding of
inactive metal
parts
