This document discusses hydraulic circuit design for machines with multiple actuators. It provides tips for identifying the sequence of actuator movements and sensor status to design the circuit. As an example, it describes a drilling machine with two double acting cylinders - one to clamp the workpiece and one to control drilling. The sequence is given as cylinder A extends, then B extends, B retracts, and A retracts. Sensors are identified for the extended/retracted positions of each cylinder.

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

3.  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)

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

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

6.  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

7.  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

8. Y1 Y4Y3Y2
A0 B1B0A1

9. 2 coil for
2 groups
4 solenoid for
Y1, Y2, Y3 & Y4

11. B+  K1 + A1

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

13. A-  K2 + B0