Schneider Electric 840 USE 106 0 manual Standby, Overview

Overview of Quantum Hot Standby

Application size For basic mechanisms (data and program transfer), the IEC HSBY and the 984 HSBY system operate in the same manner. The data transfer during normal operation, accomplished by copying the state RAM from the Primary to the Standby, causes differences in terms of application size. In IEC HSBY, a part of the state RAM is used to transport the IEC application data from the Primary to the Standby. Therefore the size of IEC application data cannot exceed the configured size of the state RAM itself. The absolute maximum for IEC application data is 128K (64K words of state RAM). For the size of an IEC application’s executable code there is also a limit of 568K under Concept 2.1/2.2. The IEC application’s executable code imit was increased to 1 Megabyte for Concept 2.5.

Quantum IEC Hot l	IEC Language programs only, no 984 Ladder Logic permitted
Standby	To bring a Standby on-line
Overview	Primary and Standby controller executives must be equal.
	Primary and Standby IEC Projects must have the same name and the
l	applications must be equal.
	On-line changes to the Primary are permitted
	With Concept 2.1/2.2, the Standby controller is taken off-line as soon as the
	first Primary on-line change is made. The Primary program must be
	ltransferred to the Standby before it can be brought back on-line.
	Concept 2.5 supports Logic Mismatch in the Hot Standby configuration
	extension. This option allows the Standby controller to remain online with a
l	different program than the primary controller.
	Primary controller on-line changes may include
	Addition of sections
	Addition of DFBs allows pre-qualification of user changes in an office
l	environment
	Logic Mismatch
	With Concept 2.1/2.2, it is not possible to load a new version of the application

lon Standby, bring it on-line, and transfer control to make it the new Primary. Under Concept 2.5, with Logic Mismatch enabled, a new version of the application can be downloaded to the Standby controller and brought online. Control can then be transferred to the Standby controller to make it the new

lPrimary controller.

To upgrade the controller Execs

With Concept 2.1/2.2, the process must be stopped. Then Primary and

lStandby controllers must be stopped and downloaded individually. Under Concept 2.5, the controller executives can be upgraded while the process continues to run.

30 840 USE 106 00 January 2003