Siemens 6MD662, Руководство пользователя

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Redundant PROFIBUS DP interface
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SIPROTEC PROFIBUS DP - Bus mapping 6MD662/3/4
C53000-L1840-B011-03
1.2 Redundancy concept
6MD663 and 6MD664 devices with redundant PROFIBUS DP interface are intended
for use in a PROFIBUS DP communication system with system redundancy.
The remarkable features of system redundancy are:
•
Redundant PROFIBUS DP master devices.
•
Redundant field bus lines.
•
Bay controller with redundant PROFIBUS DP slave interfaces.
System
redundancy
Figure 1-2 Components of a system-redundant communication system
During operation, one of the subsystems shown in Figure 1-2
•
Master #A - Field bus #A - Slave interface #A or
•
Master #B - Field bus #B - Slave interface #B
is in state PRIMARY (or process-controlling) whereas the other subsystem has the
state BACKUP (or standby).
PRIMARY The PRIMARY subsystem is the active one and has full access to the process.
Beside reading access, the PRIMARY master also can send output data to the bay
unit as well as to the process, e.g.:
•
command outputs and set-point values,
•
time synchronization of the slave devices by the master,
•
acknowledgment of read event list entries.
All these information and commands are evaluated by the PRIMARY slave interface
and passed on to the bay unit or the process outputs.
Master #A Master #B
Slave
#B
#A
Red
C
om
..
.
..
.
Master-Master communication
Field bus #B
Field bus #A