Mitsubishi Electric MELSEC FX3U Programming Manual page 806

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
2. Creating a process drawing
Create the process drawing shown on the right using
the following procedure:
1) Divide the operation described in the above
example into individual processes, and express
each process in a rectangle in the order of
operation from top to bottom.
2) Connect each process with vertical lines, and
write the condition for each proceeding process.
When performing repeated operations, indicate
with an arrow the process the truck will return to
after a series of operations finish.
3) Write the operation performed in each process on
the right side of each rectangle indicating a
process.
804
35 SFC Program and Step Ladder
Initial
process
Start switch
Truck moves forward.
1st
process
MC1 is driven.
Limit switch for minor
LS1
forward movement
Truck moves backward.
2nd
process
MC2 is driven.
Limit switch for backward
LS2
movement
Stop
Stop timer
process
Timer
Truck moves forward.
3rd
process
MC1 is driven.
Limit switch for major
LS3
forward movement
Truck moves backward.
4th
process
MC2 is driven.
Limit switch for backward
LS2
movement
35.1 SFC Program