Sfc Program - Mitsubishi Q series Programming Manual

1 GENERAL DESCRIPTION

1.1 SFC Program

The SFC program consists of steps that represent units of operations in a series of machine
operations.
In each step, the actual detailed control is programmed by using a ladder circuit.
Grouping steps into one block in process units allows to create an SFC program that is capable of
tracking all the processes as well as structuring the operation flow in each process.
Whole process
The SFC program performs a sequence of operations, beginning from the "initial" step,
proceeding to each subsequent step as the transition conditions are satisfied, and ending at the
"END" step.
(1) When the SFC program is started, the "initial" step is executed first.
(2) Execution of the initial step continues until transition condition 0 is satisfied. When this
transition condition is satisfied, execution of the initial step is stopped, and processing
proceeds to the step which follows the initial step.
Processing of the SFC program continues from step to step in this manner until the END step has
been executed.
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[Process flow chart]
Initial step
Workpiece
detection
Transition
condition 0
step 1
Transition
condition 1
Workpiece
step 2
loading
Transition
condition 2
Drilling step 3
operation
Transition
condition 3
step 4
Transition
condition 4
step 5
Transition
condition n
END step
Machining
completed
[SFC diagram] [Operation output/transition condition]
START switch, Workpiece detection
aX0 & aX1
Conveyor START
oY20
Pallet detection
aX2
Pallet clamp
oY21
Clamp confirmation
aX3
Drill rotation
oY22 ,PLS M0
pM0
Drill DOWN
sY23
Drill DOWN endpoint
aX4
Drill Down stop
rY23, oT0 K20
Workpiece unloaded confirmation
aX7
MELSEC-Q
1 operation unit
1 operation unit
1 operation unit
1 operation unit
1 operation unit
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