Siemens SIMATIC S5 Manual page 39

IP 265
Example: Segment consisting of three binary language elements (program execution time: 7.8 µs)
Two AND operations are ORed. I 0.0, I 0.1, I 0.2, I 0.3, Q 0.0 are the addresses of the
inputs or outputs of the IP 265.
&
I 0.0
I 0.1
&
I 0.2
I 0.3
Figure 4-2. Example: Binary Segment of the IP 265 User Program
Table 4-1 gives an overview of the essential differences between CPU program execution and the
IP 265 program execution.
Table 4-1. Essential Differences Between Sequential and Parallel Program Processing
Sequential program processing (CPU)
• All instructions of the CPU user program
are processed sequentially.
• The CPU user program is divided into
segments and blocks. The program can
jump from one block to another as often as
required.
• The speed of the CPU is basically
determined by the processing rate of the
instructions of the user program. The time
between reading in inputs and writing of
outputs (process image transfer) is the sum
of the individual instruction processing
times of a program run (program cycle
(PCyc)).
EWA 4NEB 812 6130-02a
>=1
Q 0.0
•
•
•
Parallel program processing (IP 265)
The IP 265 user program is processed in
parallel.
The IP 265 user program is only divided up
into segments (for editing purposes only).
The speed of IP 265 is essentially defined
by the number of retentive language
elements which are connected between the
inputs and outputs in the segments (timers,
counters and so on).
General Operation
4-3