Program Execution Time - Siemens SIMATIC S5 Manual

IP 265
4.2.1

Program Execution Time

All segments of the IP 265 user program are processed in parallel in the IP 265. For purely binary
operations, the program execution time is 1/128 kHz=7.8 µs (the interconnection is clocked with
128 kHz). Every retentive language element between an input and an output of a segment leads to
an additional extension of the program execution period of 7.8 µs in each case.
Examples of retentive language elements of the IP 265:
• Timer operations
• Counter operations
• Retentive functions, such as:
- RS flipflops
- Binary scalers
- Edge flags
- Clock delay
The different program execution times in parallel paths can lead to undesired runtime effects. For
synchronization of signal charts, the language element "clock delay" is available ( Section 9.3.2
"Language Elements in a Control System Flowchart").
Example: Program execution times of a purely binary segment
&
I 0.0
I 0.1
I 0.2
Example: Program execution times of a segment with latching language element
S
I 0.0
R Q
I 0.1
I 0.2
Figure 4-4. Examples: Program Execution Times in Parallel Paths of a Segment
EWA 4NEB 812 6130-02a
>=1
Q 0.0
>=1
Q 0.0
Hardware
Connection Processing Time
I 0.0 Q 0.0
I 0.1 Q 0.0
I 0.2 Q 0.0
Hardware
Connection Processing Time
I 0.0 Q 0.0
I 0.1 Q 0.0
I 0.2 Q 0.0
General Operation
Program
7.8 µs
7.8 µs
7.8 µs
Program
15.6 µs
15.6 µs
7.8 µs
4-5