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3.6
Display Elements
The PROFIBUS evaluation board has two LEDs on board. The green LED
D2 indicates correct power supply (3V3). The green LED D1 is connected
to the DATAEXCH output of the VPC3+ and lights up each time the VPC3+
is in state 'data exchange'.
3.7
PROFIBUS Interfaces
PROFIBUS uses a screened twisted pair cable connected to an RS485 in-
terface or a full-duplex fiber-optic link as communication medium. The
Evaluation Board offers both possibilities.
3.7.1 RS485 Interface
The RS485 interface uses differential voltages in order to be less
susceptible to interference than a plain voltage or current based interface.
The network may be configured as a daisy-chain or in a tree configuration.
The VPC3+ PROFIBUS evaluation board provides a comon 9-pin SubD
socket. This socket is used to connect the Evaluation-Kit to a PROFIBUS
network as a slave.
Each segment can support a maximum of 32 devices. Individual segments
are linked by means of repeaters. The maximum length for a segment is
determined by the transmission rate. In a PROFIBUS-DP network the
transmission rate is adjusted automatically and ranges from 9.6 Kbit/s to 12
Mbit/s. Slaves adapt their communication rate automatically. All devices
connected to the network communicate at the same transmission rate
(baudrate).
Due to the bus structure of the network any station may be connected or
disconnected without interruptions and a system can be commissioned in
different stages. Extensions to the system do not affect stations that have
already been commissioned. Any failures of stations or new devices are
detected automatically.
VPC3+S Evaluation Kit
Copyright © profichip GmbH 2009
VPC3+ PROFIBUS Board
Revision 1.00
3
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