Schneider Electric 840 USE 106 0 manual Keyswitch Override and Run Mode, Keyswitch Override Hazard

Using a Quantum 984 HSBY System

Keyswitch Override and Run Mode

Keyswitch and	You may choose to override the keyswitch on the front panel of the CHS 110
Run	modules for security or convenience. If you override the keyswitch, the command
	register becomes the means for taking the CHS 110 modules on or offline.
	By default, the keyswitch override is disabled. The Hot Standby dialog allows you to
	enable it.
Keyswitch
	If you enable the keyswitch override, the Offline/Running operating mode of the
Override	controllers at startup is determined by the values you set to bits 14 and 15 of the
	command register. These bits are represented as the Run Mode for controller A and
	B (depends on designation slide switch). Remember, that when the keyswitch
	override is enabled you can not initiate a program update (program xfer) at the CHS
	110 module in the Standby rack.
	As long as the keyswitch override is disabled, the settings for the Run Mode can be
	ignored.
		CAUTION
		Keyswitch Override Hazard
		If you use the Zoom screen or RDE to enable the keyswitch override
		while the Hot Standby system is running, the Primary controller
		immediately reads bits 14 and 15 to determine its own state and the
		state of the Standby.
		Failure to follow this precaution can result in injury or equipment
		damage.
	If both bits are set to 0, a switchover occurs and the former Primary CPU goes
	offline. The new Primary CPU continues to operate.

90 840 USE 106 00 January 2003