3.1 Basic Functionality
Programs
3-2
3.1
Basic Functionality
This section describes the basic functionality of the CPU Unit.
Programs
A program is a list of instructions to be processed by the CPU Unit.
This section describes the types of programs and gives an overview of each type.
Types of Programs
There are three types of user programs:
• Ladder programs
• Motion programs
• Sequence programs
This section describes these programs.
Ladder Programs
Ladder programs are managed as drawings (ladder diagrams) that are identified by their drawing numbers
(DWG numbers). These drawings form the basis of the user program.
Drawing Types and Hierarchical Configuration
This section describes the types of ladder drawings and their hierarchical configuration.
• Types
Ladder drawings are divided into four different types based on their purpose.
• DWG.A (Startup Drawings)
This type of ladder drawing is used to set register data. These ladder drawings are executed before
high-speed scan process drawings and low-speed scan process drawings.
• DWG.I (Interrupt Drawings)
This type of ladder drawing is used to perform processing with priority given to signals input from an
Optional Module. These ladder drawings are executed with higher priority than high-speed scan pro-
cess drawings regardless of the scan cycle.
• DWG.H (High-speed Scan Process Drawings)
This type of ladder drawing is used to perform motion control or high-speed I/O control.
• DWG.L (Low-speed Scan Process Drawings)
This type of ladder drawing is used for communications with HMIs and external devices as well as for
standard I/O control.
