Device Description MV4-670-TA1/2, MV4-690-TA1/2 3-16
Moeller 07/01 AWB-C2700-1347GB
8 Interface Connections and Cabling
8.1 Preparing the connection cable (EMC)
The preparation of the data and signal cables is an important factor for the electromagnetic compatibility
(EMC) of the MV4, both in terms of interference immunity and emission.
All data cables on the MV4 (SYSTEM PORT, PARALLEL PORT, ETHERNET) and on the cards fitted in the
slots (SYSTEM SLOT) must be shielded unless unshielded cabling is specified expressly.
The cable shield must be made from copper braid. Only use a metal or metallised connector casing. Connect
the cable shield directly to the low-impedance connector casing on the MV4 This ensures that the cable
shield is properly connected to the housing of the Panel via the screws and the protective metal shroud of the
plug connector (low-impedance).
The cables must also be shielded if they are not connected at the other end and are only used, for example,
for commissioning and servicing.
Refer to the operating instructions of the device manufacturers concerned as to how to connect the shield at
the other end. If no specifications are given, connect the cable shield also at this end to the metal or
metallised connector casing.
Avoid leaving the shield open. The data connections to be shielded involve the high-speed transfer of signals
between two active systems. The cable shield only functions against asymmetrical interference transients if
the shield is connected to the device grounds (usually metallic device casing) at both ends.
Provide a potential equalisation conductor with a suitable cross-section between potentials (control cabinets)
if the MV4 and the communications partner are installed in different control cabinets or at different PE
potentials (neutral conductor potentials), and if the cable shield at both ends is directly or indirectly connected
to the protective ground conductor. This will prevent the occurrence of large compensation currents on the
shield and shield connections. These kinds of compensation currents of normally 50 Hz even occur in normal
operation and do not represent a problem for data transmission. However, they may cause the destruction of
the shield terminals and contacts, particularly in the event of short-circuits in the environment.
Connection work should be carried out with special care in order to ensure trouble-free
operation. The EMC values stated in the technical data can only be guaranteed if the
connections and cables are prepared according to the specifications stated.
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