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Functions
Normal and Backup PLC functions
The Normal and Backup PLCs are physically and functionally identical, but their
roles differ according to whether they are in Normal or Backup state.
The Normal Premium PLC
b
Executes the application
b
Updates the outputs and inputs (in-rack and on the Fipio bus)
b
Communicates with the peripheral devices
b
Sends its database to the Backup PLC
b
Retrieves diagnostic data from the Backup PLC
b
Generates its own diagnostic data as well as that of the Premium Warm Standby
architecture
The Backup Premium PLC
b
Executes part of the application
b
Reads the state of the in-rack inputs
b
Updates its in-rack and Fipio outputs according to the state of those of the Normal PLC
b
Communicates with the peripheral devices
b
Retrieves diagnostic data from the Normal PLC
b
Generates its own diagnostic data as well as that of the Premium Warm Standby
architecture
Management of shared I/O on the Fipio bus
The Fipio bus manages the I/O exchanges on the Fipio devices. The Normal PLC is
an arbitrator for the active Fipio bus while the Backup PLC is an arbitrator for the
passive Fipio network.
Due to the characteristics of the Fipio bus, only the Normal PLC reads the physical
inputs on the Fipio bus and controls the physical outputs on the Fipio bus. The
Backup PLC does not access the Fipio bus.
During each cycle, the Backup PLC receives the values of the I/O on the Fipio bus
from the Normal PLC via the inter-PLC Ethway link (
TSX ETY 110WS
module) and
applies them to its own outputs.
This updating of the memory enables a smooth
Normal/Backup changeover
by maintaining the state of the I/O during the
changeover time.
Management of Normal/Backup states
Failure of one of the following components automatically triggers a Normal/Backup
changeover:
b
Main rack power supply
b
PLC processor
b
TSX ETY 210
communication module
b
Fipio bus connected to the integrated processor port
For all the other components, the changeover from Normal to Backup can be
customized (user-initiated changeover)
Management of optional redundant I/O
For the redundant inputs, the sensor data is transmitted to the Normal and Backup
PLCs simultaneously via the 2 input modules placed in each PLC. Two Modicon
Telefast ABE 7 16-channel sub-bases,
ABE 7ACC10
with redundant inputs and
ABE 7ACC11
with redundant outputs, can be used to perform this double wiring
easily using preformed connection cables with HE 10 connectors (see page 4/67,
items
14
,
15
,
20
and
21
).
The output values are only generated by the application processing of the Normal
PLC. This PLC sends its commands to the corresponding output modules.
During each cycle, the Backup PLC receives the Normal PLC output values via the
inter-PLC Ethway link (
TSX ETY 110WS
module) and applies them to its own
outputs.
This updating enables a smooth Normal/Backup changeover
by
maintaining the state of the outputs during the changeover time.
Management of supervision transparency (SCADA)
Transparent communication with level 2 (supervisor, third-party device, etc.) during
changeover of the PLC in Normal mode to the PLC in Backup mode is provided by
the
TSX ETY 210
Ethernet Modbus/TCP modules, using the unique IP address.
Communication with a redundant architecture is therefore similar to that with a
standard architecture.
This transparency is identical with a Modbus link, using the
TSX SCP 114
PCMCIA
card (Modbus protocol in RS 485) installed in the
TSX SCY 21601
communication
module.
Presentation:
page 4/62
Principle:
page 4/63
References:
page 4/66
Connections:
page 4/67
Functions
Modicon Premium automation
platform
Warm Standby system
PL7 Pro software
2
1
3
4
5
6
7
8
9
10