Control Expert Version Requirement

An M580 non-safety Hot Standby system can be configured using Control Expert L or XL version 11.0 or later. By contrast, an M580 safety Hot Standby system can be configured using only Control Expert XL Safety version 14.0 or higher.

PAC Hardware

Confirm that the primary PAC and the standby PAC consist of compatible hardware, including:

  • CPU

  • Rack

  • Power supply

  • Some communication modules

NOTE: No I/O modules can be mounted onto the local rack. Refer to the topic The Modicon M580 Hot Standby Local Racks for a description of modules that can be added to the local rack.

CPU Compatibility

An application created for a specific CPU may not be compatible with other CPUs. The M580 Hot Standby system compares the applications in the primary CPU against the application in the standby CPU to determine if the applications are compatible.

NOTE: An application created for a non-safety CPU cannot be run on a safety CPU, and an application created for a safety CPU cannot be run on a non-safety CPU.

For example:

  • A Quantum 140CPU67•6• CPU Hot Standby application is not downloadable to M580 BMEH58•040 Hot Standby CPUs.

  • An M580 BMEP58•0•0 CPU application is not downloadable to M580 BMEH58•040 Hot Standby CPUs.

  • As described in the following table, an application designed for one M580 BMEH58•040 Hot Standby CPU may not be downloadable to other M580 Hot Standby CPUs.

The following table depicts the compatibility of applications among non-safety M580 Hot Standby CPUs:

An application built for:

Can be downloaded to and executed by the following CPUs:

BMEH582040

BMEH584040

BMEH586040

BMEH582040

X

X

X

BMEH584040

–

X

X

BMEH586040

–

–

X

X: Can receive and execute the application.

–: Cannot receive and execute the application.

The following table depicts the compatibility of applications among M580 safety CPUs:

An application built for:

Can be downloaded to and executed by the following CPUs:

BMEP582040S

BMEP584040S

BMEH582040S

BMEH584040S

BMEH586040S

BMEP582040S

1

2

2

4

4

BMEP584040S

3

1

3

4

4

BMEH582040S

2

2

1

2

2

BMEH584040S

3

2

3

1

2

BMEH586040S

3

2

3

3

1

  1. Fully compatible.

  2. Compatible, if CPU is upgraded in Control Expert and the application is fully rebuilt.

  3. Compatible, if CPU is upgraded in Control Expert and the application is fully rebuilt, and there is no limitation as to memory size.

  4. Compatible only for application with no CIP Safety devices, if CPU is upgraded in Control Expert and the application is fully rebuilt.

CPU Firmware Mismatch

An M580 Hot Standby system can continue operating when there is a mismatch of firmware versions in the primary and standby CPUs, if each CPU firmware can execute the application. This makes it possible to upgrade (or downgrade) CPU firmware without having to stop the operation of the Hot Standby system. To permit Hot Standby operations to continue in this case, use an animation table or program logic to set the FW_Mismatch_Allowed attribute of the T_M_ECPU_HSBY to True.

Application Mismatch

An M580 Hot Standby system cannot operate if the primary and standby CPUs are equipped with fundamentally different applications. In this case, the primary PAC operates as a standalone PAC, and the standby PAC enters the stop state.

To restore Hot Standby system operations, confirm that the same application is installed in both the primary and standby PACs.

Logic Mismatch

An M580 Hot Standby system can continue operating if the primary and standby CPUs are running different revisions of the same application. In this case, both CPUs were initially configured with the same application, but the logic in one CPU – usually the primary CPU – was subsequently revised.

For Hot Standby operations to continue when a logic mismatch exists, use an animation table or program logic to set the Logic_Mismatch_Allowed attribute of the T_M_ECPU_HSBY DDT to True .

For Hot Standby operations to continue when a logic mismatch exists, do both of the following:

  • Select Online modification in RUN or STOP in the Configuration tab of the CPU.

  • Set the Number of modifications in the Configuration tab of the CPU.

  • Use an animation table or program logic to set the Logic_Mismatch_Allowed attribute of the T_M_ECPU_HSBY DDT to True .

NOTE: If the Number of modifications is set to 0, setting the Logic_Mismatch_Allowed attribute has no effect.

SFC Mismatch

A sequential function chart (SFC) mismatch occurs when the applications in the primary and standby CPUs include graphic symbols that define sequential program steps, where differences exists in at least one SFC section.

Refer to the topic Modifying an SFC Section Online for the recommended procedure for making online modifications to an SFC section.