PC Control / Profi Control 645-12M Instruction Manual pdf - Kuhnke

Purpose of PC Control 645-12M
1.2. Summary of PROFIBUS-DP features
PROFIBUS is a field bus. Its name is an acronym of the term
"Process Field Bus". DP stands for "Decentralised Periphery".
It was developed to network controllers (such as PC Control
645-12M, Profi Control 680I, Modu Control 657P etc.)
while providing an interface to the field level, i.e. to sensors
and actuators (e.g. via decentralised input/output devices
such as Profi I/O 690E or 680S).
Open communication
The principle of open communication is meant to guarantee
interconnections between devices of different manufacturers.
The standard for this field bus is set in Euronorm "EN
50 170, Volume 2, PROFIBUS".
Topology
PROFIBUS is normally constructed as a line, but a tree
structure is also possible. The number of stations on any
one line is limited to 32. Where that is not enough, a second
line can be opened which is connected to the first line
by a bidirectional line amplifier (repeater). Repeaters also
count as stations so that the number of "real" stations on
one line is reduced to 31 (or 30 with 2 repeaters).
The number of bus stations can thus be increased to up to
122 by applying up to 3 repeaters.
Station address
Each PROFIBUS station is assigned its own station address
under which it can be addressed by the other stations.
Valid addresses are in the range of 0 to a maximum of
126. PC Control 645-12M has assigned its station address
by VEBES, the network configurator.
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