hydraulic

2.  Hand in assignments!
 Mid term test 2 weeks from now.
 Same day, time and place.
 CO1, CO2 and CO3 only (hydraulics, electro-hydraulics
and pneumatics)
 Good luck!

3.  Relevancy:
1. Used to build Continuous Cycle circuit.
2. Used to latch a circuit for continuous supply of
electricity to a particular line.
3. Used when replacing a double solenoid valve to a
single solenoid valve of a circuit, without changing
the originality of the circuit function.

4.  Memory ON (Dominant Set)
+24V
0V
ON
K1
K1
OFF
K1
• When ON is pressed, Relay coil K1
will be energized. Both relay K1
switches will close. This means, while
the lamp turns on, the relay switch will
continuously energize the coil.
Therefore, the lamp is permanently on.
Only when the OFF button is pressed,
the lamp will switch off.
• To confirm that this is a Memory ON
circuit, press both ON and OFF
together. The lamp will still light ON.

5.  Memory OFF (Dominant Reset)
• The function of this circuit is
similar to the previous Memory
ON circuit. However, please
note that the OFF button is
placed below the ON button,
not parallel!
• To confirm that this is a
Memory OFF circuit, press both
ON and OFF together. The lamp
will NOT light ON.
+24V
0V
ON
K1
K1
OFF
K1

6.  Proximity -> closeness
 Detect close objects without contact.
 Various types:
1. Inductive sensor
2. Capacitive sensor
3. Optical sensor

7. Used to sense only metal type of object.

8. Used to sense only high density objects.

9. Used to sense only reflective type of object.

11.  More than 1 actuator
 1 cylinder needs 1 valve
 Tips for circuit design:
◦Identify sequence of movement
◦Identify limit switch/sensor status

12.  Example:
 A hydraulic actuated drilling machine
contains two double acting cylinders
(DACs). When the work piece is
located at its position, cylinder A will
clamp the work piece. Then, the
drilling process starts, where the
spindle is controlled by cylinder B.
After completion of drilling, cylinder
B will retract to the initial position,
before the clamping cylinder
retracts.
 Sequence: A (extend) -> B (extend) -
> B (retract) -> A (retract)

13.  Identify sequence of movement
A+ B+ B- A-
F=0 F=0
Cylinder A Cylinder B
A 0 A 1 B 0 B 1

14.  Make the group
 A group must contain different elements
 1 group represents 1 coil
A+ B+ B- A-
K1 K2

15.  Identify limit switch/sensor status
A+ B+ B- A-
A1 B1 B0 A0
F=0 F=0
Cylinder A Cylinder B
A 0 A 1 B 0 B 1
<= Actions
<= Sensors

16.  Rephrasing the sequence and limit
switch/sensor status
A1 B0
A+ B+ B- A-
Start B1 A0
Right
side of
circuit
Left
side
of
circuit

17. Y1 Y4Y3Y2
A0 B1B0A1

18. 2 coil for
2 groups
4 solenoid for
Y1, Y2, Y3 & Y4

20. B+  K1 + A1

21. B-  K2 + B1 K2 due to changing group

22. A-  K2 + B0