Lenze DDS v2.3 - Manual (Page 211)

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DDS EN 2.3
I/O Display whether inputs (IN) or outputs (OUT) of the system block are concerned.
Module no. Module number of the associated system organization unit
(for module numbers refer associated manual for the automation system or online help, chapter
“Lenze automation systems”)
Module name Name of the system organization unit
Task name Name of the task where the associated process image of a system organization unit is generated or written.
• Either the task name selected in the task configuration or the cyclical task or system task
(certain system organization units are assigned to the system task).
• The system automatically determines the optimized time cycle for the system organization unit.
Interval This column specifies the time cycle for process image updates.
Tip!
Check before the download whether all applied system organization blocks are listed in the dialog
box
Process image to detect errors quickly.
8.5.1 Generating the process image
The process image consists of
•
Process input image = Status of all system organization unit inputs
•
Process output image = Status of all system organization unit outputs
Cyclical task (PLC_PRG)
If only one cyclical task is used, the process input image of the system organization units used for
this task will be read at the beginning of the cyclical task, and the process output image will be
restored at the end of the cyclical task.
•
During processing of the automation system program, the status information of the process
input image will remain constant, and data consistency is ensured.
•
Process image updates depend on the processing time of the cyclical task, in other words,
program length and complexity.
Time-controlled task (INTERVAL)
If INTERVAL tasks are used, the process input image of the system organization blocks used for this
task will be read at the beginning of the INTERVAL task and the process output image be restored
at the end of the INTERVALtask.
•
If a certain system organization unit is used in several INTERVAL tasks, the associated
process image will be generated in the faster INTERVAL task (independent of whether this
system organization unit is also used in the cyclical task).
Tip!
Note that the INTERVAL task may be slower than the cyclical task.
It may be necessary to install a fast task for the process image to ensure that only the process image
is updated in time.
Example:
Analog input 1 is used in the cyclical task (runtime: 40 ms) and in an INTERVAL task
(runtime: 3 ms).
•
The process image for analog input 1 is now updated every 3 ms. The cyclical task receives
an updated value every 3 ms during processing (40 ms).
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