User's Manual

Redundancy 27
Redundancy
Increasing the plant availability
For the individual telecontrol protocols, reference was already
made as to how the availability of telecontrol communication
can be increased using redundant transmission paths. How-
ever, as a result of seamless integration of the telecontrol
technology into the SIMATIC PCS 7 process control system, the
redundant design of the telecontrol communication is embed-
ded in the redundancy concept of the complete system and
must therefore be considered globally.
The example of a SIMATIC PCS 7 process control system
with integral telecontrol linking of RTUs on the basis of
the IEC 870-5-101/IEC 870-5-104 protocols demonstrates the
various possibilities for increasing plant availability:
• Redundant SIMATIC PCS 7 TeleControl OS servers for pro-
cess control of central and widely distributed units and for
archiving
• Redundant system bus for system communication
• Redundant telecontrol communication between control
center and RTUs over two separate transmission paths
• Redundant RTUs on the basis of S7-400H/ S7-400FH con-
trollers for local automation of remote units
• Redundant PROFIBUS for communication between control-
ler and process I/O (I/O modules, process instruments and
devices in the field)
• Redundant process I/O
It is also possible to implement safety-related functions in
the RTU (up to SIL 3) based on the S7-400FH controller and
F modules in the ET 200M remote I/O station.
Redundant telecontrol configuration based on the
IEC 870-5-101/IEC 870-5-104 protocols
G_PCS7_XX_00274
SIMATIC PCS 7
OS clients
Control center
SIMATIC PCS 7
TeleControl OS
with redundant
servers
Redundant system bus
Terminal bus
IEC 870-5-101
redundant
IEC 870-5-104
redundant
TCP/IP to serial
converter
RTU S7-400H
RTU
S7-400H
with CP 443
TCP/IP
WAN router
ET 200M
redundant
ET 200M redundant
with 2 x CP 341
© Siemens AG 2011