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Elektronik GmbH
Page 9 of 45
POS-124-*-PDP-1121
13.02.2013
3 Use and application
3.1 Installation instructions
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This module is designed for installation in a shielded EMC housing (control cabinet). All cables
which lead outside must be screened; complete screening is required. It is also a requirement
that no strong electro-magnetic interference sources are installed nearby when using our control
and regulation modules.
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Typical installation location:
24V control signal area (close to PLC)
The devices must be arranged in the control cabinet so that the power section and the signal sec-
tion are separate from each other.
Experience shows that the installation space close to the PLC (24 V area) is most suitable. All
digital and analogue inputs and outputs are fitted with filters and surge protection in the device.
•
The module should be installed and wired in accordance with the documentation bearing in mind
EMC principles. If other consumers are operated with the same power supply, a star- connected
ground wiring scheme is recommended. The following points must be observed when wiring:
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The signal cables must be laid separately from power cables.
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Analogue signal cables
must be shielded.
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All other cables must be screened if there are powerful interference sources (frequen-
cy converters, power contactors) and cable lengths > 3m. Inexpensive SMD ferrites
can be used with high-frequency radiation.
•
The screening should be connected to PE (PE terminal) as close to the module as
possible. The local requirements for screening must be taken into account in all cases.
The screening should be connected to at both ends. Equipotential bonding must be
provided where there are differences between the connected electrical components.
•
With longer lengths of cable (>10 m) the diameters and screening measures should
be checked by specialists (e.g. for possible interference, noise sources and voltage
drop). Particular care is required with cables of over 40 m in length – the manufacturer
should be consulted if necessary.
•
A low-resistance connection between PE and the mounting rail should be provided. Transient in-
terference is transmitted from the module directly to the mounting rail and from there to the local
earth.
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Power should be supplied by a regulated power supply unit (typically a PELV system complying
with IEC364-4-4, secure low voltage). The low internal resistance of regulated power supplies
gives better interference voltage dissipation, which improves the signal quality of high-resolution
sensors in particular. Switched inductances (relays and valve coils connected to the same power
supply) must always be provided with appropriate overvoltage protection directly at the coil.
