Schneider Electric 840 USE 106 0 manual Efficient Use, IEC Application, Anything else, Data

Additional Guidelines for IEC Hot Standby

Configured State	With Concept 2.2 the mirror buffer does not exist anymore, but it’s still worth not
RAM Registers,	having significantly more state RAM references configured than actually used.
Continued	The actual use of state RAM references should concentrate on I/O purposes only
	and not on storing some application data, just to make it accessible for a SCADA
	system. The better way would be to use any kind of application related data, which
	includes everything except I/O points, pure IEC variables (non located variables).
	The connection to the SCADA system can then be accomplished more easily with
	an OPC (OLE for Process Control) server, that accesses certain application data by
	name and not by location. This method of SCADA connection is very flexible and
	reliable and saves state RAM, which is good for IEC Hot Standby applications.
Efficient Use of
	There is one thing that can reduce the IEC application data consumption better than
IEC Application	anything else:
Data
	Program only what’s really necessary to control a particular process.
	When learning about IEC compliant programming and the different EFBs in the
	different libraries, concentrate on which EFBs not to use. This will help you reduce
	the size of an application to the necessary minimum.

156 840 USE 106 00 January 2003