Table of Contents
Advertisement
2.2.2 Subroutine program
(1) Definition
Subroutine program is a program from a pointer (P ) to the RET instruction.
This program is executed only when it is called by a subroutine program call instruction (such as
CALL(P), FCALL(P)) from a main routine program.
(2) Application
• Programming a program which is executed two or more times in one scan as a subroutine
program can reduce the number of steps in the entire program.
• Programming a program which is executed only when a certain condition is satisfied as a
subroutine program can shorten the scan time.
(3) Programming of subroutine programs
(a) Programming location
Create subroutine programs between the FEND and END instructions in the main routine program.
Subroutine programs can be managed as one separate program (stand-by type program).
(
Section 2.2.3)
(b) Programming order
When creating multiple subroutine programs, it is not necessary to set the pointer numbers in
ascending order.
Remark
For the nesting of subroutine programs, refer to Section 9.9.
Program A
P0
Subroutine
program
P8
P1
Figure 2.6 Programming location of subroutine programs
CHAPTER2 SEQUENCE PROGRAMS
Main routine
program
FEND
Y10
RET
Y11
RET
Y12
RET
END
1
2
3
4
5
6
7
8
2 - 5
Advertisement
Table of Contents
