4 Understanding Programming
4-2
CP1E CPU Unit Software User’s Manual(W480)
4-1 Programming
User programs are created by using the CX-Programmer.
The user programs consist of the following parts.
• Programs
A program consists of more than one instruction and ends with an END instruction.
• Tasks (Smallest Executable Unit)
A program is assigned to an interrupt task to execute it. (In the CX-Programmer, the interrupt task
number is specified in the program properties.)
Tasks include cyclic tasks (executed with normal cyclic processing), interrupt tasks (executed when
interrupt conditions have been completed) and scheduled interrupt tasks (executed at specified inter-
vals).
The CP1E can use only one cyclic task.
• Sections
When creating and displaying programs with the CX-Programmer, the one program can be divided
into any number of parts.
Each part is called a section.
Sections are created mainly to make programs easier to understand.
• Subroutines
You can create subroutines within a program.
The user programs are saved in a project file (.CXP) for the CX-Programmer along with other parame-
ters, such as the symbol table, PLC Setup data, and I/O memory data.
Programs can be written using only ladder programs.
4-1-1 User Programs
Structure of User Programs
User Program Data
Programming Languages
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