Schneider Electric 840 USE 106 0 manual 2Operation, Modes of Operation

Overview of Quantum Hot Standby

1.2Operation

Modes of Operation

HSBY Modes of HSBY has three Modes of Operation:

Operation

1.Off Line Mode

2.Transfer Mode

3.Run Mode

These modes are described below.

Off Line Mode This mode is used to take a controller out of service without stopping it or disconnecting power. If you turn the key on the Primary unit to Off Line, control switches to the Standby. If the Standby controller is taken offline, the Primary continues to operate without a backup.

Transfer Mode This mode is used to request a program update of the Standby controller from the Primary controller. For a step-by-step description of the procedure refer to Replacement, p. 192.

The Primary controller is able to update the Standby without any interruption in its other functions. If the Primary unit is in Run mode and you hold down the update button on the Standby unit, the Hot Standby modules prepare to copy the full program of the Primary controller to the Standby unit. The program includes the configuration table, I/O map, configuration extensions, segment scheduler, user logic, all .EXE loadables, ASCII messages and the entire state RAM.

To complete the transfer, while continuing to press the update button, turn the key on the Standby to transfer. The Com Act LED extinguishes. Turn the key to the mode you want the Standby to assume after the update, Run or Off Line. The Standby indicator flashes. Release the update button.

The Standby indicator continues to flash during the update and while the Standby unit processes the update. If the unit is set to run mode, the Standby indicator returns to a steady amber. If the unit is set to offline mode, the Standby indicator extinguishes. Remove the key.

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