Справочник Пользователя для Mitsubishi Electronics FX2NC

FX Series Programmable Controlers

5-11

An FEND instruction indicates the first end of a main program and the start of the program
area to be used for subroutines. Under normal operating circumstances the FEND instruction
performs a similar action to the END instruction, i.e. output processing, input processing and
watchdog timer refresh are all carried out on execution.

a) The FEND instruction is commonly used with CJ-P-FEND, CALL-P-SRET and I-IRET

program constructions (P refers to program pointer, I refers to interrupt pointer).
Both CALL pointers/subroutines and interrupt pointers (I) subroutines are ALWAYS
programmed after an FEND instruction, i.e. these program features NEVER appear in the
body of a main program.

b) Multiple occurrences of FEND instructions can be used to separate different subroutines

(see diagram above).

c) The program flow constructions are NOT allowed to be split by an FEND instruction.

d) FEND can never be used after an END instruction.

FEND
FNC 06
(First end)

Used to indicate
the end of the
main program 
block

N/A
Note:
Can be used with CJ (FNC 00), CALL (FNC 01)
and interrupt routines

FEND:
1 step

FX

0(S)

FX

0N

FX FX

(2C)

FX

2N(C)

FEND

X10

P 20

CJ

FEND

FEND

X11

P 21

CJ

END

END

P20

P21

0

0

I100

Main program

Main program

Main program

Main program

Subroutine

Main program

Main program

Interrupt prog'

X10
=
OFF

X10
=
ON

X11
=
ON

X11
=
OFF