Schneider Electric 840 USE 106 0 manual Transfer All State RAM, Check box Nontransfer Area

Using a Quantum 984 HSBY System

Transfer All State RAM

"Transfer All	It is not possible to define a special State RAM or additional State RAM range to be
State RAM"	transferred if this check box is activated.
check box
Nontransfer Area
	The nontransfer area contains the Hot Standby status register, which is used to
	monitor the states of both controllers. It also contains a pair of registers which may
	be used for reverse transfer operations. You may include other 4x registers in the
	nontransfer area to reduce scan time.
	The Start: field is used to specify the first 4x register in the nontransfer area. The
	Length: field is used to define the number of contiguous registers in the nontransfer
	block. If you choose to define a nontransfer area, the range of legal values for this
	entry field is 4 ... n, where n is the number of configured 4x registers. However, when
	defining the nontransfer area, you must meet these requirements:

The nontransfer area must be located entirely within the area of 4x registers scheduled for transfer on every scan. The transfer area is defined in the State

lRAM dialog.

The command register (first entry of the Hot Standby dialog) must be outside the nontransfer area.

Note: If you are also programming a CHS instruction in LL984, the parameters you set for the nontransfer area in the Hot Standby dialog must be identical to those in the CHS block.

Hot Standby lThe third register in the nontransfer area is the Hot Standby status register. Use

Status Register this register to monitor the current machine status of the Primary and Standby controllers.

94 840 USE 106 00 January 2003