Fig 13
Optional high frequency decoupling for 70 V /
100 V systems.
Conclusion:
Because the Intellivox can be a part of a complex
installation it is impossible to prescribe a fixed
grounding strategy that will perform best in all
situations. Safety, immunity and reduction of emission
are very important issues that should always determine
the ground configuration that is applied.
This appendix describes some methods to eliminate
possible noise caused by ground loops without
sacrificing safety or emission, although a minor
degradation of the immunity can be expected which is
depending on the configuration chosen.
Fig 14
Structure of the RS-485 network
3.3 Some notes on the RS-485
network interface.
In order to integrate the unit in a surveillance and
control network a full duplex RS-485 terminal is
incorporated. The RS-485 standard is chosen for the
ability of driving long cables, the simplicity of the
network topology and high immunity to external
electromagnetic fields which results in low error rates.
A disadvantage of the full duplex set up is the required
5 wire interface. The RS-485 interface on the unit
exists of a differential input port (AB), a differential
output port (YZ) and a dedicated network ground
terminal (DGND).
Intellivox DDC |
Installation Manual
|
Appendix
Bosch Security Systems | July 2003
EN
| 17
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