Behavior of the Redundancy System when Calling Commands

Login command, then Login with Download command

Downloads the application on PLC 1

On PLC 1, the application is stopped and removed. Then the new application is downloaded. During this time, the standby PLC 2 switches to redundancy simulation mode. After some time, PLC 2 attempts to trigger a synchronization. The attempt is repeated every 10 seconds.

The synchronization is triggered successfully only after PLC 1 is started.

Login command, then Login with Online Change command

Executes an online change on PLC 1

On the active PLC 1, the application is stopped and then removed. Then the new application is downloaded. During this time, the standby PLC 2 switches to redundancy simulation mode. After some time, PLC 2 attempts to trigger a synchronization. The attempt is repeated every 10 seconds.

The synchronization is also triggered successfully as soon as PLC 1 starts the application. After a successful synchronization, PLC 2 switches to standby mode.

If it takes longer than 10 seconds for PLC 1 to start, then PLC 2 switches to error mode. Also in error mode, PLC 2 attempts to trigger a synchronization.

Command: Reset Warm

Executes a simultaneous warm start on both PLCs

The redundancy task is still synchronized. The redundancy state active/standby remain unchanged.

Command: Reset Cold

Executes a simultaneous cold start on both PLCs

The redundancy task is still synchronized. The redundancy state active/standby remain unchanged.

Command: Reset Origin

Executes a reset origin on both PLCs

The redundancy task is still synchronized. The redundancy state active/standby remain unchanged.

Command: Reset Origin Device

Executes a reset origin on PLC 1

At this time, the most important settings are removed from the runtime configuration files. The redundancy state is set to redundancy simulation mode.

Command: Start

Starts the application on PLC 1

As a result, the synchronization is triggered.

After a successful synchronization, PLC 2 switches to standby mode and PLC 1 is active.

If it takes longer than 10 seconds for PLC 1 to start, then PLC 2 switches to error mode. Also in error mode, PLC 2 attempts to trigger a synchronization.

Command: Stop

Command: Single Cycle

Stops the application on PLC 1

As a result, PLC 2 switches to redundancy simulation mode. After some time, PLC 2 attempts to trigger a synchronization. The attempt is repeated every 10 seconds.

Breakpoints

No support in the redundancy system

The commands are executed on PLC 1 only.