Siemens SITRANS T3K PA Instruction Manual page 108

7NG3213
7 PROFIBUS
The PROFIBUS-PA (PA = Process Automation) is a variant of the PROFIBUS DP
(DP = Decentral Peripheral) which is widely used in manufacturing engineering.
The PROFIBUS (Process Field Bus) is an open communication system for
automation engineering and is used in its thousands all over the world. It is
specified in the European standard EN 50170.
7.1 Transmission technology
The PROFIBUS PA has a special transmission technology and therefore satisfies
the requirements of process automation and manufacturing engineering. This
transmission technology is defined in the international standard IEC 61158-2. The
low transmission speed reduces the power loss in relation to the PROFIBUS-DP
and therefore enables an intrinsically safe technique for use in hazardous areas.
7.2 Topology
The bus topology can largely be selected freely so that line, star and delta
structures as well as mixtures of these are possible. All types of field devices such
as measuring instruments, actuators, analyzers etc. can be connected.
The main advantage is in:
D saving of installation costs
D possibility of further diagnostics with increase in the availability of system parts
D possibility of automatic tracing of system documentation
D possibility of system optimization in operation
Several PROFIBUS PA channels are usually connected with the fast PROFIBUS-
DP by coupling units in an automation system. The process control system is also
connected to this.
Both bus systems use a common protocol layer. The PROFIBUS-PA is therefore a
"communication-compatible" expansion of the PROFIBUS-DP in the field.
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Instruction Manual
SITRANS T3K PA
C79000-B7174-C55-04