770
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
34 SFC Program and Step Ladder
34.2 Step Ladder
Output driving method
It is required to include a LD or LDI instruction before the last OUT instruction in a state relay.
Change such a circuit as shown below.
State relay transfer method
Each OUT and SET instructions in state relays automatically resets the transfer source, and has the self-
holding function.
OUT instructions can be used only for transfer to a separate state relay in an SFC program.
Replacing “
” and “
V
”
Replace the symbol “
” used in SFC programs to express repeat, jump or transfer to a state relay in another
separate flow with the OUT instruction.
Replace the symbol “
V
” (used to express reset of a state relay) with the RST instruction.
Y001
Change
Y002
Y003
Y001
X005
Y002
Y003
Move the
position.
Y001
M8000
Y003
Y002
Insert a NC
contact.
X005
RUN
monitor
or
STL
S20
STL
S20
STL
S20
X005
Change
S50
STL
S41
SET
S42
Transfer
condition
Transfer to the next state relay
(SET instruction)
Transfer to a separate state
relay (OUT instruction)
41
40
Y001
1
X001
X003
X001
X002
TRAN
2
3
X003
TRAN
X004
TRAN
X002
X004
Y001
STL
S40
SET
S41
S52
STL
S41
RST
S41
Replacement of “ ”
in the part 52
Replacement of “ ”
in the part 41
<Step ladder>
<SFC program>
52
41