Overview Of The Memory Concept Of S7-400 Cpus - Siemens SIMATIC S7-400 Reference Manual

Memory Concept and Startup Scenarios
2.1

Overview of the Memory Concept of S7-400 CPUs

Subdivision of the Memory Areas
You can divide the memory of the S7 CPUs into the following areas:
2-2
External load memory
RAM with battery backup or
retentive flash
memory
Integrated load memory
RAM with battery backup
Working memory code
For the program
RAM with battery backup
Process input and output
image
Diagnostic buffer
Working memory data
For data
RAM with battery backup
Local data stack
System memory
Contains memory marker, timers,
counters,
block stack and interrupt stack
RAM with battery backup
Load memory
For project data (blocks,
symbols, comments, configu-
ration and
parameter assignment data)
Working memory
For runtime-relevant blocks
Automation System S7-400 CPU Specifications
A5E00165965-01