Profibus-Dp - Weidmuller SAI Active Universal Pro Series Manual

SAI Pro
2.2

PROFIBUS-DP

PROFIBUS
PROFIBUS (PROcess Field BUS) is a part of the
international standards IEC 61158 and IEC 61784.
Physically, PROFIBUS is either an electrical network
based on a shielded, two conductor cable or an opti-
cal network based on a fibre optics cable.
PROFIBUS-DP (DP = Decentralised Periphery) is a
special application for automating factory production.
System
A typical PROFIBUS-DP system is made up of
• at least one PLC or industrial PC (master) operat-
ing as a control system
• various field devices, which can be digital or ana-
logue I/O devices, AC or DC drives, magnetic or
pneumatic valves, frequency converters, starters,
operating and display devices (slaves)
Figure 3 Basic PROFIBUS system configuration
14
Data transfer
Data exchange within the system is carried out by
means of cyclic polling. The master establishes
communications with one slave at a time, makes
data available and/or requests data. The slave being
addressed responds immediately to the request for
data. Once completed, this procedure is repeated
with the other slave devices. This is a continuous
cyclic process.
GSD files (device database files)
The GSD file is the obligatory "ID card" of each and
every PROFIBUS device. It contains the characteris-
tic data of the device, details about its communica-
tion capabilities as well as further information such
as diagnostic values. All GSD files for the SAI Active
Universal range of SAI distributors can be
downloaded from Weidmueller's website at:
http://www.weidmueller.com/54266/Downloads/Soft
ware/SAI-Active-Data/cw_index.aspx?newsid=
For more information, please refer to
Chapter "Commissioning the PROFIBUS-
DP".
5663600000/1.4/09.09