Chapter 4. CPU module
4 - 9
4.3 Program
4.3.1 Program Configuration
A program consists of all of the function elements that is needed to execute a particular control. It is to be
stored in the internal RAM of the CPU module or the flash memory of the memory module.
The function elements are classified as below.
Function
Elements
Processing Operation
Initialization
program
•
Executed when the power is applied or the CPU operation is transited to the RUN
mode.
•
Executes the initial/fixes data setting for execution of scan program and the
initialization of peripheral devices on special modules.
Scan program
•
Processes the constantly repeated signals which are executed every scan.
Time driven task
program
•
When the following time conditional processing is required the program is executed
complying with the time interval setting.
4
In case that the processing need a shorter interval than that of average one scan
processing time.
4
In case that the processing need a longer interval than that of average one scan
processing time.
4
In case that the processing should be executed by the specified time interval.
Event driven task
program
•
A shorter processing is executed for internal or external interrupt.