Elements Of An Application Program; Structure Of An Application Program - GE VersaMax PLC User Manual

8 Elements of an Application Program

8.1 Structure of an Application Program

Elements of an Application Program
For public disclosure
This chapter provides basic information about the application program for a VersaMax
PLC.
• Structure of an application program
• Subroutines
• Program languages
• The Instruction Set
The application program consists of all the logic needed to control the operations of the
PLC CPU and the modules in the system.
Application programs are created using the programming software and transferred to the
PLC. Programs are stored in the CPU's non-volatile memory.
During the CPU Sweep (described in the previous chapter), the CPU reads input data
from the modules in the system and stores the data in its configured input memory
locations. The CPU then executes the entire application program once, utilizing this fresh
input data. Executing the application program creates new output data that is placed in the
configured output memory locations.
After completing the end of the application program, the CPU writes the output data to
modules in the system.
Read Inputs
Execute
Application
Program
Write Outputs
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