Siemens SIMATIC S5-100U System Manual page 120

Addressing
The following table gives an overview of the most important system data in the system data area.
System data
word
5 to 7 ISTACK (Interrupt STACK)
8 to 12 Integral real-time clock
33 First free program memory address
35 Program memory starting address
37 Program memory end address
40 to 45 CPU version, software release
57 to 63 SINEC L1
96 Scan monitoring time (value
97 Calling interval for OB 13 for time-controlled program
processing (value
128 to 159 BSTACK (Block STACK)
203 to 214 ISTACK (Interrupt STACK)
6-16
Table 6-6. System Data Area Assignment
Contents
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10 ms)
10 ms)
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S5-100U
Chapter/
Section Reference
5.2
12
13
7.4.4
5.3.2
5.2
EWA 4NEB 812 6120-02b