SCS P4dragon DR-7800, Руководство по установке

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6. Connectors
6 Connectors
6.1 Grounding and Shielding
The
P4
dragon
has several connectors where cables can be or must be attached for a proper
operation. All this cables should be and are shielded. The shield is usually connected to the
shelf of the connector. Each connector of the
P4
dragon
will get in contact with the cable shield
and feeds the
shield
signal to a ground plane on the bottom side of the printed circuit board
(PCB). Every connector has its own
shield
ground plane and they are separated to maintain
signal isolation.
All connectors of the
P4
dragon
are isolated from each other by DC/DC converters, data-
isolators, transformers or photo-couplers, so also their shields are. This done for safety and to
avoid parasitic currents to flow. But in operation environments where all devices connected to
the
P4
dragon
use a common ground anyway, it may be desirable or recommended to “catch
up” all the shields as a common signal and to connect it to the systems grounding or “earthing”
stud. The
P4
dragon
provides the possibility to do this, so system integrators may want to use
this way of installation. As most of the radios and computer devices have the shield and the
signal ground connected together, this way of installation certainly
removes
the isolation
which the
P4
dragon
normally provides.
To archive a
shield
signal common with all connectors, the
P4
dragon
must be opened (as
explained in chapter 5.3.3). Turn the bottom side up and observe the rear area of the PCB
where the connectors are placed. You will see separated ground planes associated with every
connector. There are solderable areas on the borders of all the ground planes where they can be
soldered together. This creates a large and common ground plane to all shields which is
connected to the outside with the
Shield
pin of the GPS connector. This pin should be used to
tie the shield signal to the system grounding point.
Figure 16: Connecting the shield ground planes together
6.2 The Audio Connectors in General
Due to the variety of possible transceiver types which can be used with the
P4
dragon , it is
somewhat more difficult to find out the correct connection. For many common transceivers
complete manufactured cables are available as accessory (chapter 10 on page 89). For all the
others the attached DIN-8 pigtail cable must be used and completed by the user. Your dealer
will be helpful to find the proper connection scheme.
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