Logix5555TM
POWER
RUN
ControlNET
BAT
PRIM
A#01
RS232
OK
CHA CHB OK
RUN
A-B
Quality
REM
Logix5555 TM
RUN
OK
PROG
ControlNET
BAT
A#02
Redundancy Module
SYNC
OK
CHA CHB OK
RUN
ControlLogix
Redundancy
I/O
RS232
Quality
PRI COM
Allen-Bradley
POWER
A-B
Redundancy Module
I/O
REM
PRI COM OK
PROG
Allen-Bradley
1
Main Redundancy Features
• Optimized for availability of control.
• Absolutely no user programming required to implement.
• Bumpless switchover guaranteed for any outputs controlled by logic
in the highest priority task.
• Switchover within approximately 100 msec.
• Works with standard Logix5555 controllers and ControlNet Bridges
(Series D or higher).
• Switchovers are transparent to any devices networked to the
redundant controller chassis.
• Transparent cross-load of programs from primary to secondary
controllers.
• On-line workstation configuration/commands/edits to primary are
automatically forwarded to secondary.
• User can choose to cancel or resume ‘test edits’ at switchover.
Rockwell Automation Confidential
2
Building a Typical Redundant System
Logix5555™
RUN
A-B
Quality
Allen-Bradley
RS232
BAT
ControlNET
A#01
Quality
Allen-Bradley
ControlNET
A#01
COM OK
Redundancy Module
PRIM
OK
CHA CHB
RUN
PRI
Start with a standard ControlLogix chassis.
Add 1 or more Logix5555 processors.
Add 1 or more ControlNet Bridges (Series D).
Add 1 System Redundancy Module.
Set up an identical second controller chassis.
Cable the SRMs together.
Add I/O, operator interfaces, and so forth to the
ControlNet network(s).
I/O
RS232
BAT
OK
REM PROG
Logix5555™
RUN
A-B
PRIM
OK
CHA CHB
RUN
Redundancy Module
I/O
1.
2.
3.
4.
5.
6.
7.
OK
PRI
COM OK
REM PROG
Rockwell Automation Confidential
3
Other Redundant Architecture
Considerations
• Only Logix5555’s, ControlNet Bridges, and a single System
Redundancy Module can be placed in a redundant controller chassis.
– All I/O must be remote from the redundant controller chassis.
– To connect to other networks, bridge through another ControlLogix
chassis.
Ethernet
A-B
Quality
Allen-Bradley
RUN
A-B
Quality
Allen-Bradley
RUN
BAT
BAT
ControlNET Redundancy Module
Logix
5555 I/O
™ RS232 A#
P
OK
R
01
CHA CHB OK PRI COM OK
I
RUN REM PROG
M
ControlNET Redundancy Module
Logix
5555 I/O
™ RS232 A#
P
OK
R
01
CHA CHB OK PRI COM OK
I
RUN REM PROG
M
ControlNet
Rockwell Automation Confidential
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Logix5555 Controller
• New CPU ASIC
– Provides alternative memory parity encoding method so
that higher density commercial memory may be used.
– New memory change detection algorithms for
Redundancy.
• New circuitry to support new 1.5, 3.5, and 7.5 Mbyte
memory cards.
• Increased Performance
– Faster Flash-Memory to increase operating system
performance.
– Movement of Floating Point library to RAM for higher
performance (30% faster than L1).
• Hardware changes to support ControlLogix
redundancy.
• New Real Time Clock (RTC) chip with increased
accuracy.
• In redundancy, data is buffered in the secondary
controller, so twice as much data memory space is
required.
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5
ControlNet allows transparent switchovers
• The 1756-CNB Series D has added the
necessary hardware and firmware changes to
support ControlLogix redundancy.
• You set the same ControlNet address on the
rotary switches of the primary and secondary
CNB’s.
– The primary CNB will use that address, and the
secondary CNB will automatically use the next
higher address.
• On a switchover, the CNB’s automatically swap
addresses.
– Any external ControlNet devices will simply
continue to communicate with the new primary
controller.
– ControlLogix redundancy works transparently with
1756 I/O, Flex I/O, drives, operator interfaces, or
any other Rockwell or third-party devices which
can communicate to a Logix5555 over ControlNet.
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6
System Redundancy Module
• The 1757-SRM provides the high speed
data transfers between the primary and
secondary chassis and arbitrates
primary/secondary chassis status.
• Two slot module
• Only one SRM per chassis needed.
Redundancy Module
PRIM
PRI COM
OK
– We will test with up to four Logix5555
processors per chassis.
• A fiber optic cable connects the primary
and secondary SRM’s.
– 1757-SRC1, SRC3, or SRC10 (1, 3, or 10
meter lengths)
Rockwell Automation Confidential
7
1757-SRM Configuration
• The 1757-SRM module will be configured from RSLinx instead of
RSLogix 5000.
– Allows one 1757-SRM to support multiple Logix5555 controllers.
– Similar to how DHRIO and ENET modules are configured using RSLinx 2.2.
Rockwell Automation Confidential
8
SRM Dialog Module Info Tab
Provides identification of the
module.
Provides the general status of
the module.
1757-SRM REDUNDANCY MODULE
Identifies the
current
redundancy
state of this
chassis. This is
visible from
every tab on the
dialog.
Chassis_B: Primary with Qualified
Secondary
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9
SRM Dialog Configuration Tab
Select when you want a disqualified secondary chassis
to automatically attempt synchronization.
• Always
• Never
• Conditional - Auto-synchronization enabled on
a Synchronize Secondary command and
disabled on a Disqualify Secondary command.
Lets you specify whether this
chassis should be referred to as
Chassis A or Chassis B.
Select whether
programmed messages
from a Logix5555 are
allowed to trigger
redundancy
commands (initiate
switchover, disqualify
secondary, etc.)
Set the date and time
to be used in the
SRM event log.
Chassis_B: Primary with Qualified
Secondary
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10
SRM Dialog Synchronization Tab
Issues a manual
command to attempt
to synchronize the
secondary chassis to
make it available for
switchover.
Issues a manual
command to
disqualify the
secondary chassis to
make it unavailable
for switchover.
Issues a manual
command to switch
control to the
secondary chassis.
This can be used to
test the redundant
system.
Issues a manual
command allowing a
disqualified
secondary chassis
with no partner to
take control.
1757-SRM REDUNDANCY MODULE
Shows the result of
the last four
synchronization
attempts of the
redundant system.
Chassis_B: Primary with Qualified
Secondary
Rockwell Automation Confidential
11
SRM Dialog Chassis Profile Tab
• Shows the current state of all the modules in this
redundant controller chassis.
Shows the
Shows the progress
of synchronization
in percent.
Shows the
secondary’s
readiness to take
control.
Shows the state of
the modules
(startup, faulted,
etc).
compatibility
between the
primary and
secondary module.
1757-SRM REDUNDANCY MODULE
Chassis_B: Primary with Qualified
Secondary
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12
SRM Dialog Event Log Tab
• This dialog shows the history of the past 10 events.
• Events that are logged include synchronizations,
switchovers, etc.
• This information is stored on the SRM module.
1757-SRM REDUNDANCY MODULE
Chassis_B: Primary with Qualified
Secondary
Rockwell Automation Confidential
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No programming required
• A primary Logix5555 automatically determines what data changes
during its scan and automatically sends that data to its secondary
Logix5555. You don’t have to program messages or even specify
certain data areas to transfer. It all just happens automatically.
You just select a single
checkbox on the
controller properties
dialog to enable
redundancy.
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14
Other Controller Properties Options
Allows you to specify whether you want test
edits to remain in effect after a switchover.
This is useful for online edit changes.
This
enables
redundancy.
Lets you specify how much of
the unused memory will be
allocated for adding data online
versus adding program online.
Here you can see the status of this
controller chassis and this
controller.
Here you can see the status of this
controller’s redundant partner.
Rockwell Automation Confidential
15
Automatic cross-loading of programs
Logix5555™
RUN
A-B
Quality
Allen-Bradley
A#01
Quality
Allen-Bradley
ControlNET
A#01
COM OK
Redundancy Module
PRIM
OK
CHA CHB
RUN
PRI
I/O
RS232
BAT
OK
REM PROG
Logix5555™
RUN
A-B
PRIM
OK
CHA CHB
RUN
Redundancy Module
I/O
RS232
BAT
ControlNET
OK
PRI
COM OK
REM PROG
Rockwell Automation Confidential
• You only have
to download
your program
to the primary
controller.
The system
will
automatically
cross-load the
primary’s
program to the
secondary
controller.
16
Bumpless Switchovers
• The secondary controller is synchronized with the
primary to provide a bumpless switchover for any
outputs controlled by logic in the highest priority
task:
– Primary notifies secondary when user tasks start.
– Primary notifies secondary when programs complete &
provide a complete data ‘snapshot’.
• Secondary doesn’t execute programs, but follows along,
pending at each program start.
• Incomplete transfers are ‘quarantined’ on secondary until
complete.
– At switchover, the new primary rolls back to the
beginning of currently executing programs using ‘last
good’ data snapshot.
Rockwell Automation Confidential
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ControlLogix Redundant Power Supply
1756-PA75R / -PB75R
Power Supplies
• 85 - 265 VAC and 19 - 32 VDC
Versions
• Panel mount (1756-A4 footprint 6.9" H x 5.7" W x 5.4" D)
• Px75 equivalent capacity
1756-CPR Cables
• 3 foot max length
• Pin-outs provided if you want to
make shorter cables
1756-PSCA
Chassis Adapter Module
• Passive device funnels power
to backplane
• Series B chassis only
Failure Annunciation
• Normally Open solid state relay on each supply
• Wire to any input module
Rockwell Automation Confidential
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