Mitsubishi Electronics FX3G User Manual

FX

3S

/FX

3G

/FX

3GC

/FX

3U

/FX

3UC

 Series

Programming Manual - Basic & Applied Instruction Edition

35 SFC Program and Step Ladder

FNC277

-F

NC2
79

Da

ta

 

Trans
fer 3

FNC28

0-F

NC
289

H

igh-Speed 

Process

ing 2

FNC2

90-
FNC299

Ex

tensi

on Fi
le

 

Register C

ontrol

FN

C300-

FNC30

5

FX

3U

-C

F-

AD

P

SFC

•STL

Programming

Interrupt 

Function

Sp

ec

ia

l D

evi

ce

E

rror Code

Ve

rsi

on U

p 

Inform

ati

on

Ex

ecuti

on

 T

imes

Step ladder programs and SFC programs are substantially the same as described above, but actual programs are
expressed as shown below.
A step ladder program is expressed as a relay ladder, but it can be created according to the machine control flow
using state relays.

SET

S0

X000

SET

S20

STL

S20

Process of S0

STL

S0

M8002

Start

Y021

Moving
forward

Y023

X001

SET

S21

STL

S21

Y023

Moving
backward

Y021

X002

SET

S22

STL

S22

T0

K50

T0

SET

S23

STL

S23

Y021

Y023

X003

SET

S24

STL

S24

Y023

Y021

S0

X002

RET

END

It is necessary to input the RET

instruction in a program.

Y023

Y021

Ladder block

SFC block

M8002

SET

S0

Program for setting to

ON an initial state relay

State number and transfer condition

number are indicated.

0

20

0

1

21

2

22

3

23

4

24

5

S0

RET

END

X000

TRAN

Y021

Y023

X001

T0

X002

Y023

Y021

T0

Y021

Y023

X003

X002

K50

TRAN

TRAN

TRAN

TRAN

TRAN

Internal
circuit

<Step ladder>

<SFC program>

Start

Can be converted
each other

Moving
forward

Moving
backward

Process of S20

Process of S21

Process of S22

Process of S23

Process of S24

Moving
forward

Moving
backward

Moving
forward

Moving
backward

When a program is input 

using GX Works2 and GX Developer, 

“RET” and “END” are automatically 

written.