ControlLogix Redundancy

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ControlLogix Redundancy
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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.

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Building a Typical Redundant System
1. Start with a standard ControlLogix chassis.
2. Add 1 or more Logix5555 processors.
3. Add 1 or more ControlNet Bridges (Series D).
4. Add 1 System Redundancy Module.
5. Set up an identical second controller chassis.
6. Cable the SRMs together.
7. Add I/O, operator interfaces, and so forth to
the ControlNet network(s).
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Other Redundant Architecture Considerations

• Only Logix5555s, 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
ControlNet
5
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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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 CNBs.
• The primary CNB will use that address, and the
  secondary CNB will automatically use the next
  higher address.
• On a switchover, the CNBs 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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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.
• We will test with up to four Logix5555 processors
  per chassis.
• A fiber optic cable connects the primary and
  secondary SRMs.
• 1757-SRC1, SRC3, or SRC10 (1, 3, or 10 meter
  lengths)

Redundancy Module
PRIM
PRI COM OK
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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.

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SRM Dialog Module Info Tab
Provides identification of the module.
Provides the general status of the module.
Identifies the current redundancy state of this
chassis. This is visible from every tab on the
dialog.
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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.
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SRM Dialog Synchronization Tab
Issues a manual command to switch control to the
secondary chassis. This can be used to test the
redundant system.
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 allowing a disqualified
secondary chassis with no partner to take control.
Shows the result of the last four synchronization
attempts of the redundant system.
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SRM Dialog Chassis Profile Tab

• Shows the current state of all the modules in
  this redundant controller chassis.

Shows the compatibility between the primary and
secondary module.
Shows the secondarys readiness to take control.
Shows the state of the modules (startup, faulted,
etc).
Shows the progress of synchronization in percent.
13
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.

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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
  dont 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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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.
Lets you specify how much of the unused memory
will be allocated for adding data online versus
adding program online.
This enables redundancy.
Here you can see the status of this controller
chassis and this controller.
Here you can see the status of this controllers
redundant partner.
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Automatic cross-loading of programs

• You only have to download your program to the
  primary controller. The system will
  automatically cross-load the primarys program to
  the secondary controller.

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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 doesnt 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.

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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