Device Description MV4-150-TA1, MV4-450-TA1, MV4-170-TA1, MV4-470-TA1 1-15
Moeller 07/01 AWB-C2700-1347GB
7 Connection to the communication interface
7.1 Preparing the connection cable (EMC)
The preparation of the data and signal cables is an important factor for the electromagnetic compatibility
(EMC) of the Touch Operator Panel, both in terms of interference immunity and emission.
All data cables on the Touch Operator Panel (PROG PORT) and on the card in the slot (COM SLOT) must
be shielded unless unshielded wiring is specified explicitly. Cables connected to the communications
interface must be laid separately to low-voltage cables when they come together (cable ducts in separate
partitions).
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 unit. This ensures that the cable
shield is properly connected to the housing of the Touch Operator 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 earths (usually metallic device enclosure) at both ends.
Provide a potential equalisation conductor with a suitable cross-section between potentials (control cabinets)
if the Touch Operator Panel and the communications partner are installed in different control cabinets or at
different PE potentials (zero conductor potentials), and if the cable shield at both ends is directly or indirectly
connected to the protective earth 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.
Special care should be taken with the connection to ensure interference-free operation.
The EMC values stated in the technical data can only be guaranteed if the cables are
manufactured according to the specifications.
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