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4 SFC PROGRAM CONFIGURATION
MELSEC-Q
(b) When the SET, basic or application instruction is used
If a transition to the next step occurs and the corresponding step becomes inactive, the
device remains ON or the data stored in the device is held.
To turn OFF the ON device or clear the data stored in the device, use the RST instruction,
etc. at another step.
Step “n”
Step “n+1”
Transition
condition “n”
Example:
sY0
When transition condition “n” becomes satisfied at the
step “n” operation output where Y0 is ON (by SET
instruction), the Y0 ON status will be maintained even
after the transition to step “n + 1”.
(c) When the oC
instruction is used:
1) The counter counts once every time the transition condition is satisfied and the
corresponding step that is inactive is activated.
St ep n
Transition
condit ion n
Example:
oC0 K10
Counter C0 counts once when transition condition n is
satisfied and execution proceeds to step n.
2) To cause the counter to count once when the input condition turns ON and execution to
proceed to the next step when the counter counts up,
• Create a counter ladder in a sequence program; or
• Create an SFC diagram using a jump transition on MELSAP-L.
In the program example shown below, the counter counts once every time X10 turns
ON, and execution proceeds to the next step when C0 counts up.
When creating counter ladder in sequence program
When using jump transition on
MELSAP-L
When creating program with
MELSAP3
aX0
aC0
C0
X10 K5
Waiting for count-up
Ladder described in ot her scan
execut ion program file (ot her
than SFC)
aX0
aX10
aC0
oC0 K5
n
n
bX10 & bC
X0
Tran
C0
Tran
C0
X10
K5
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