Справочник Пользователя для Mitsubishi Electronics FX5

1  PROGRAM EXECUTION

1.5  Program Type

Programs that use pointers (P) or interrupt pointers (I) are explained below.

This is the program from pointer (P) up to the RET instruction. Subroutine programs are executed only when they are called 
by the CALL instruction. Pointer type labels also can be used instead of pointers (P). The applications of subroutine programs 
are as follows:
 • By grouping programs that are executed multiple times in one scan into a single subroutine program, the number of steps 

in the entire program can be reduced.

 • A program that is executed only under certain conditions can be saved as a subroutine program which shortens the scan 

time proportionately.

 • Subroutine programs can also be managed as separate programs by turning them into standby type 

programs. (Page 28 Stand-by type program)

 • Pointers need not be programmed starting with the smallest number.

The precautions when using subroutine programs are explained below.
 • Do not use timers (T, ST). Note, however, that timers can be used when a timer coil (OUT T instruction) is always 

executed only once in one scan.

 • An error occurs when program execution returns to the call source program and the program is terminated without using 

the RET instruction.

 • An error occurs when there is no pointer (P) or pointer type global label in FB or FUN.

RET

END

P1

RET

Y12

RET

Y11

P8

P0

FEND

Y10

Subroutine program 1

Subroutine program 2

Subroutine program 3

Pointer

Main routine program