Matakuliah
Tahun
Versi
: Mechatronics 2
: 2005
: 1.0/0
Week 5
SEQUENTIAL MOTION (LDR)
1
Learning Outcomes
• By the end of this session, students can
develop Ladder Diagram to perform
sequential motions.
2
Sequential Motion
• Sequential motion is meant to be
performing 1 motion after the others.
• Performing sequential tasks in a parallel
like fashion.
• The use of flags will overcome this
problem.
• Latching concept.
• Controller and actuator concept.
• Latching concept in performing a
sequential motion.
3
Flags & Latching Concept
• Flag is an internal relay and is most often
used to memorize events.
• It must be declared in an allocation list
prior to using it.
• Flags can be used in both conditional part
and executive part.
• Latching concept allows to create a single
solenoid valve to act as a double solenoid
valve.
4
Implementation of Latching
Concept
S1
( F0,0)
F 0,0
F 0,0
( L1 )
5
Implementation of Latching
Concept (continued)
• F0,0 = internal relay utility
• If S1 switch (normally open) is pressed,
then electric current will flow through F0,0
coil and F0,0 switch will be closed
accordingly.
• A latch condition will occur.
6
• A latch condition can be stopped by
adding a normally closed switch into the
system.
• This switch is required to cut the current
which is flowing through F0,0 coil.
• As no more current flow through F0,0 coil,
the F0,0 switch will open and stop the
latching condition.
7
Stopping the Latched Condition
S1
S2 (NC)
( F0,0)
F 0,0
F 0,0
NC = normally closed
( L1 )
8