Siemens SIMATIC S5 Manual page 226

IP 265 Sample Applications and Programming Aids
13.1.3 Sample Program with Expansion and Parameter Interchange
Sample application for case c):
Controlling a subprocess with expansion and parameter interchange between IP 265 and CPU.
If an IP 265 user program cannot be implemented on a single IP 265 because a of its size or
because of the number of digital inputs/outputs needed, the IP 265 can be expanded to include a
second IP.
The IP 265 user program is then divided into two programs, one for each IP. The two programs are
then rejoined via the expansion interface.
The sample program shows an expansion which became necessary because the number of digital
inputs on one IP 265 was insufficient. In addition to expansion, the two IPs interchange parameters
with the CPU.
Sample application: Fast shutdown in the event of a malfunction
The sample application is described in detail in Section 12, "IP 265 Expansion".
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EWA 4NEB 812 6130-02a