775
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
34 SFC Program and Step Ladder
34.2 Step Ladder
31
FN
C
275-FN
C
279
Da
ta
Tr
ans
fe
r 3
32
FN
C
280
-F
N
C
28
9
H
igh Speed
Pr
oces
si
ng 2
33
FN
C
290-FN
C
299
Ext
ensi
on Fi
le
R
egi
st
er
34
SF
C
•S
T
L
Pr
o
g
ra
m
m
in
g
35
In
te
rru
p
t
Funct
ion
36
Sp
e
cia
l De
vic
e
37
E
rro
r C
o
d
e
A
V
e
rs
ion U
p
In
fo
rm
a
tio
n
B
Ex
ec
ut
ion Ti
m
e
s
C
Appl
ic
ab
le
In
st
ru
ct
ion Li
st
4) Parallel recombination and selective branch
34.2.7
Program examples
Examples of single flows
1. Example of flicker circuit
• When the PLC mode is changed from STOP to RUN, the state relay S3 is driven by the initial pulse
(M8002).
• The state relay S3 outputs Y000. 1 second later, the ON status transfers to the state relay S20.
• The state relay S20 outputs Y001. 1.5 seconds later, the ON status returns to the state relay S3.
<List program>
STL
STL
LD
SET
STL
LD
SET
LD
SET
103
20
1
X000
TRAN
X000
STL
S20
SET
S103
S20
S30
X000
S103
S103
X001
S40
X002
S50
30
2
40
50
X001
TRAN
3
X002
TRAN
STL
S30
X001
SET
S40
STL
S103
X002
SET
S50
<Step ladder>
<SFC program>
Dummy state
1
second
1.5
seconds
Y000
Y001
LD
SET
STL
OUT
OUT
LD
SET
STL
OUT
OUT
LD
OUT
RET
END
SET
S3
M8002
S3
S3
Y000
T0 K10
T0
S20
S20
Y001
T1 K15
T1
S3
STL
S3
T0
STL
S20
SET
S20
M8002
Y000
K10
T0
T1
RET
Y001
K15
T1
END
0
1
3
4
5
8
9
11
12
13
16
17
19
20
Step
number
0
3
4
8
11
12
16
19
20
Initial pulse
S3
<List program>
<Step ladder>
Step
number