Mitsubishi Electronics Mitsubishi Digital Electronics Video Gaming Accessories FX3G ユーザーズマニュアル

239

/FX

3UC

Series Programmable Controllers

Programming Manual - Basic & Applied Instruction Edition

8 Program Flow – FNC 00 to FNC 09

8.10 FNC 09 – NEXT / End a FOR/NEXT Loop

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Errors

1. Watchdog timer error

When FOR-NEXT loop is repeated many times, the operation cycle (D8010) is too long, and a watchdog timer error
may occur. In such a case, change the watchdog timer time or reset the watchdog timer.

→ For details on changing the watchdog timer time, refer to Subsection 37.2.2.

→ For resetting the watchdog timer, refer to WDT (FNC 07) instruction.

2. Examples of wrong programs

The following programs are regarded as errors.

Program example

1. Program with three FOR-NEXT loops

When NEXT instruction does not exist

FOR

When NEXT instruction is located before FOR
instruction

FOR

When number of FOR instructions is not
equivalent to the number of NEXT instructions

FOR

← Not programmed

FOR

When NEXT instruction is located after FEND or
END instruction

FOR

FEND

END

← Not programmed

The loop [3] is repeated 4 times.

When the data value (current value) of D0Z
(D4 when Z is "4") is "6", the loop [2] is
repeated 6 times.

When X010 is OFF

When K1X000 is "7", the loop [1] is repeated
7 times.

When X010 is ON

The program execution jumps to the pointer P22,
and the loop [1] is skipped.

Number of times of repeating the loops [1],
[2] and [3]

X010 = ON

X010 = OFF

× 6 × 4 =168 times

× 4 = 24 times

4 times

[1]
[2]
[3]

0 time

24 times

4 times

X010

P 22

[1]

[2]

[3]

FNC 09

FNC 08

FOR

K 4

FNC 08

FOR

D 0Z

FNC 00

P 22

FNC 08

FOR

K1X000

FNC 09

7
times

6
times

4
times