Schneider Electric 840 USE 106 0 manual IEC Hot Standby Definitions, IEC runtime system, Including

Theory of IEC HSBY Operation

IEC Hot Standby Definitions

Definitions	The following are IEC Hot Standby definitions.
	Exec: Quantum controller operating system with integrated IEC language support
	(IEC runtime system)
	Program Data: A continuous memory block containing all program variables,
	including:

Non-located IEC variables and constants declared in variable editor

Links in FBD and LD sections

Stack (loop) variables in IL and ST

SFC states

Literals

Pointer lists

Internal states of EFBs

DFB Instance Data: Multiple memory blocks containing: Internal data of each DFB instance

Process diagnostics buffer

Mirror buffer: 1 Byte per configured 0x/1x reference (only Concept 2.1 and older)

Used references list: 1 Bit per configured 0x/1x reference

IEC Heap: One continuous memory block containing:

lProgram data DFB instance data

Maximum IEC Heap Size: 128 KByte together with state RAM. If 10K Words (20 KByte) of state RAM are used already for I/O references the max. IEC heap size would be 128 KByte – 20 KByte = 108 KByte

Currently used IEC Heap Size: DFB instance data plus (configured) program data area size

State Table: Also called state RAM, controller references for both real world I/O and internal referenced (located) variables

Project: Concept program file containing controller configuration and IEC language control code

Application: Downloaded IEC language control code and data

44 840 USE 106 00 January 2003