2.8.3
Standby type program
Standby type program is executed only when its execution is requested. This type of program can be changed to any
desired execution type by a program instruction. This program is mainly used for the following purposes.
• Program library
Standby type program is used as a program library, a collection of subroutine programs and/or interrupt
programs, and managed separately from a main routine program. Multiple subroutine programs and/or
interrupt programs can be created and managed in a single standby type program.
Scan execution type program
• Program type change
Standby type program is used to create and store programs available in all systems. Only required programs
will be executed. For example, a program preset as a standby ("Wait") type program in the PLC Parameter
dialog box can be changed to a scan execution type program and executed in the program.
(1) Execution method
Execute standby type programs in either of the following methods.
• Create subroutine and interrupt programs in a standby type program and execute the standby program upon
interrupt or a call such as by a pointer.
• Change a standby type program to any other execution type using instructions.
Main routine
program
Subroutine
P100
program
Interrupt
I0
program
CHAPTER 2 APPLICATION OF PROGRAMMING
Scan execution type program
Main routine
program
Standby type program
P100
Subroutine
program
Interrupt
I0
program
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