Technical data

9.1 Introduction
The STEP 5 programming language contains operations with which
you can access the entire memory area. These operations belong to the
"system operations".
Caution
If the operations described in this section are not used properly,
STEP 5 blocks and system data can be overwritten. This can
result in undesirable operating statuses. Only experienced system
programmers should use operations that work with absolute
addresses.
Local memory Local memory is the memory area available in each CPU (user
submodule, DB-RAM, RI, RJ, RS, RT area, counters, timers, flags,
process image).
Global memory Global memory only exists once for all CPUs and is addressed via the
S5 bus.
Memory organization Memory areas are organized in bytes or words as follows:
•• bytes: each address addresses a byte
•• words: each address addresses a 16-bit word
(= 2 bytes)
Introduction
CPU 928B Programming Guide
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