Supplementary information
15.15 Cycle and response times of the CPU 410-5H
CPU 410-5H Process Automation
System Manual, 09/2014, A5E31622160-AB
311
Processing direct I/O access
You can achieve faster response times by directly accessing the I/O in your user program,
e.g., with the following instructions:
●
L PIB
●
T PQW
However, note that any I/O access requires a synchronization of the two units and thus
extends the cycle time.
Reducing the response time
This reduces the maximum response time to
●
Delay of the inputs and outputs
●
Runtime of the user program (can be interrupted by higher-priority interrupt processing)
●
Runtime of direct access
●
2x bus runtime of DP
The following table lists the execution times of direct access by the CPU to I/O modules. The
specified times are pure CPU processing times and do not include the processing times of
the signal modules.
Table 15- 15 Direct access of the CPUs to I/O modules in the central controller
Access type
CPU 410-5H
stand-alone mode
CPU 410-5H
redundant
Read byte
Read word
Read double word
Write byte
Write word
Write double word
2.2 µs
3.7 µs
6.8 µs
2.2 µs
3.8 µs
7.0 µs
11.0 µs
11.1 µs
14.2 µs
10.8 µs
11.2 µs
14.4 µs
Table 15- 16 Direct access of the CPUs to I/O modules in the expansion unit with local link
Access type
CPU 410-5H
stand-alone mode
CPU 410-5H
redundant
Read byte
Read word
Read double word
Write byte
Write word
Write double word
5.5 µs
10.5 µs
19.9 µs
5.3 µs
10.2 µs
19.8 µs
13.0 µs
17.9 µs
27.4 µs
12.7 µs
17.6 µs
27.3 µs