Siemens SIPAN 32 Instructions De Service page 83

PROFIBUS PA
J
( field devices, decentral periphery, subordinate
controls, network transition to PROFIBUS PA)
Fig. 4-7 Example of a Profibus automation system
Dispositif de mesure de conductivité SIPAN 32
C79000-B5477-C045-02
MPIP sarl - 94, rue Mohamed Tounsi - 16013 - ROUIBA - ALGERIE
Tél./Fax : 021 81 11 22 - GSM : 070 91 75 15 ou 072 900 654 - E-mail : mpip@mpi-dz.com
As a rule, several PROFIBUS PA channels are connected to 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" extension of the PROFIBUS DP into the
field.
Master
(class 1)
PROFIBUS DP
Slaves
Figure 4-7 shows a section of a typical PROFIBUS automation system.
The control system consists of two masters with distributed tasks.
The class 1 master takes care of the control and regulating tasks, the
class 2 master enables the operating and monitoring functions. A cyclic
exchange of measuring and setting data takes place between master 1
and the field devices. The status information of the field devices is
transmitted parallel to these data and evaluated in the class 1 master.
Parameterization of the field devices or reading of further device
information takes place in acyclic mode.
The information necessary for setting up cyclic communication is
available to the control system by the stored device--specific device
data files GSD (see section 4.8.16").
Mise en service et fonctionnement
Master
(class 2)
PROFIBUS PA
J
4-37