WAGO-I/O-SYSTEM 750
CoDeSys 2.3 Runtime Environment 119
758-874/000-131 WAGO-I/O-IPC-C6
Manual
Version 1.0.0
11.7.1
Cyclical Task Priorities
You can assign a priority for each task in order to establish the task processing
sequence.
All tasks that access the process image of the I/O module are synchronized with it.
This means that the tasks with access to the process image of the internal data bus
wait until at least one correctly completed internal data bus cycle has been
executed.
If there is an error on the internal data bus (e.g. defective I/O module), the tasks
that access the process image of the internal data bus are no longer executed.
These tasks can only be processed when there is new input data available to them.
Figure 51: Changing the task name
Priorities of the task processing
The priorities below do not specify the sequence of the task processing. The tasks
are started in any sequence.
Priority 0 – 5:
Important arithmetic operations and highly synchronized accesses to I/O module
process images should be carried out as tasks with the highest priorities 0-5. These
tasks are fully processed according to priority and correspond to LinuxRT
priorities -68 through -63.
Priority 6 – 10:
Real-time accesses such as accesses to the ETHERNET, file system, fieldbus
(only for I/O-IPC with fieldbus connections) and RS-232 interface should be
carried out as tasks with the average priorities 6-10. The tasks are fully processed
according to priority and correspond to LinuxRT priorities -50 through -46.