Schneider Electric 840 USE 106 0 Function, Keyswitch, Designation, Slide Switch, Update Button

Overview of Quantum Hot Standby

Function	Beneath the LED display on the face of each CHS 110 control panel is a function
Keyswitch	keyswitch. It has three positions: Off Line, Xfer (transfer) and Run. You may use this
	switch to force transfer of control functions or to copy the full program from the
	Primary controller to the Standby.
	The following illustration shows a function keyswitch with three positions: Off LIne,
	Xfer and Run.
	Off
	Line	Xfer

Run

	Note: For security or convenience, you can disable the function keyswitch with a
	software override. Once the keyswitch is disabled, you can set the module to run
	or offline mode with software. This can be especially helpful when the module is
	not easily accessible.
Designation
	A slide switch located below and to the right of the keyswitch is used to designate
Slide Switch and	the controller as A or B. One unit must be designated as A and the other as B.
Update Button	Use the Standby Update Button to initiate the Primary to Standby program transfer.
	You must have the keyswitch in transfer mode.
	Note: If the controllers are given identical designations, the system refuses to
	acknowledge them both. The first unit to power up will be recognized as the
	Primary controller. It is designated A or B according to its switch position. The
	second unit remains offline and the ComAct indicator flashes, indicating a startup
	error.
	Note: Once the system is running, Primary control may be exchanged between the
	units regardless of which is designated as A or B.

20 840 USE 106 00 January 2003