Exercise 1: Realising a sorting device Training aims • To familiarise yourself with the design and mode of operation of a single-acting cylinder. • To familiarise yourself with the design and mode of operation of a 3/2-way solenoid valve. • To be able to identify and draw various types of actuation of directional control valves. • To be able to explain and design an example of direct actuation. Problem definition A sorting device is to be used to sort water samples according to the size of the sample bottle. Design a control system whereby this process can be carried out. Parameters
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Exercise 1: Realising a sorting device
Training aims
• To familiarise yourself with the design and mode of operation of a single-acting
cylinder.
• To familiarise yourself with the design and mode of operation of a 3/2-way
solenoid valve.
• To be able to identify and draw various types of actuation of directional control
valves.
• To be able to explain and design an example of direct actuation.
Problem definition
A sorting device is to be used to sort water samples according to the size of the
sample bottle. Design a control system whereby this process can be carried out.
Parameters
• A single-acting cylinder is to be used.
• The control of the cylinder is to be effected by means of a pushbutton.
• In the event of a power failure the cylinder piston rod is to return into the
retracted end position.
Project task
1. Answer the questions or carry out the exercises regarding the fundamentals of
the training contents listed.
2. Draw the pneumatic and electrical circuit diagram.
3. Simulate the electropneumatic circuit diagram and check its correct
functioning.
4. Compile an equipment list.
5. Carry out the pneumatic and electrical circuit assembly.
6. Check the circuit operation.
Positional sketch
Sorting device
1. Pressing of a pushbutton causes the piston rod of a single-acting cylinder to
push the sample bottle off the conveyor.
2. When the pushbutton is released, the piston rod is to return into the retracted
end position.
Fundamentals: Function of pneumatic working components
Pneumatic working components can be divided into two groups:
• Working components using linear movement
• Working components using rotary movement
– Describe the function of the working components shown.
Single Acting Cylinder Normally Extended
Single Acting Cylinder Normally Retracted
Rotary Actuator
Fundamentals: Completing solenoid valve symbols
– Complete the individual symbols with the help of the corresponding component
Fundamentals: Normal positions of directional control valves
An electrically actuated 3/2-way solenoid valve has two switching positions. It can be in
the normal position (unactuated) or in the switching position (actuated). In the normal
position the valve can be open or closed.
– Describe the effects on the motion sequence of the following application arising as a
result of the different normal positions. The single-acting cylinder shown is controlled by
an electrically actuated 3/2-way solenoid valve.
Fundamentals: Direct and indirect actuation
An electrically actuated solenoid valve can be actuated either directly or indirectly.
– Describe the difference with the help of the following application: Electrical actuation
of a spring-returned 3/2-way solenoid valve using a pushbutton.
If the electricity flows and actuates the 3/2 way valve compress air will flow to the single acting cylinder.
If the electricity flow is stopped, the 3/2 way valve will return to its original position and stop the compress air flowing through the single acting cylinder.
Design and function of an electrical switch
Switches are basically divided into pushbutton and control switch designs and perform
the function of a normally open or normally closed contact or changeover switch.
– Describe the design and function of the switches shown.
Electricity is connected directly to the solenoid valve without the use of relays.
Electricity is connected to relays then connected to solenoid valve.
Fundamentals: Mode of operation of different valve types
Electrically actuated directional control valves are switches with the help of solenoids.
Basically, these can be divided into two groups:
• Spring-return solenoid valves
Make switch with push button - if the buttons is activated the circuit will be closed as long as it is still pushed.
Break switch with detent push button – if the button is pushed the circuit will be open, if the button is released it is still open circuit until the button is push again.
Change over with push button - if the button is pushed the circuit will change to another circuit.
• Double solenoid valves
– Describe the differences between the two groups with regard to function and
behaviour in the event of power failure.
Fundamentals: Port designations of valves
A valve that has a spring-return that can return to its original position without the compressed air.
A valve that needs compressed air so that it can return to its original position.
In order to prevent incorrect tubing up of directional control valves, the valve ports
(working and pilot lines) are identified in accordance with ISO 5599, both on the valve
itself and in the circuit diagram.
– Describe the meaning and function of the designations below.
Exhaust
The one that actuates
The one that actuates also
Exercise 2: Realising a shut-off device
Compare these two valve types (directly actuated valve and pilot actuated valve) and
describe the respective advantages and disadvantages:
Directly actuated valve – A directly actuated valve is when the push button is
pressed, current flows directly to the valve solenoid, allowing the directional
control valve to be turned on.
Pilot actuated valve – A pilot actuated valve uses a relay to indirectly turn on the
directional control valve. When the push button is pressed, the current passes
through the relay first (which lowers the amount of current that passes through)
and will then pass through the valve solenoid to turn the circuit on.
Describe the meaning and function of the designations below:
4 – port connected to the closed end of the cylinder. Air is exhausted when the
cylinder is retracted and the air flows through here to extend the cylinder.
14 – a port for a double-piloted direction control valve wherein when air flows
through here, it changes its state (left side of valve) where air flows through (4)
and exhausts through (2). It will stay at this state until it is turned off and when
port 12 (right side) is turned on.
82/84 – two electromagnetic pilot valves for operating a Valve 10’
Describe the mode of operation of the directional control valve shown:
4 2
5
1
3
1M1
- The control valve shown is to be actuated by means of a valve solenoid (with or
without the use of a relay). When the pushbutton is pressed, current will flow
through the valve solenoid which will then allow the compressed air to pass
through, and thus allowing the cylinder to function. Since it is spring returned, it
will go back to its original state when the pushbutton is released.
Describe the meaning of the cylinder symbol shown:
A double acting cylinder connected to port 4 (left closed end) and port 2
(right open end). In a retracted position, air enters through (2) and
exhausted at (4). In an extended position, air flows through (4) and exhausted at (2).
The right double acting cylinder has the same function as
the one above. The left one is connected differently. At the
retracted position, air flows through (4) and exhausts at (2). At the extended position, air
flows through (2) and exhausts at (4).
Designing the pneumatic and electrical circuit diagram
Equipment list:
- Double acting cylinder
- One way control valve (2)
- Directional control valve, spring returned
- Valve solenoid
- Pushbutton, normally open
EXERCISE 3: REALISING A LID PRESS
Training aims:
To familiarize yourself with the design and mode of operation of a double-acting
cylinder.
To be able to explain and design an example of an indirect actuation.
Problem definition:
In a filling plant, wall or ceiling paints are filled into plastic pots. Once filled, slip-
lids are to be pressed onto the plastic pots.
A double acting cylinder is to be used.
The cylinder control is to be effected indirectly and by means of a pushbutton. In
the event of power failure the cylinder piston rod is to return into the retracted
end position.
Project Task
1. Answer the questions or carry out the exercises regarding the fundamentals of
the training contests listed.
2. Design the pneumatic and electrical circuit diagrams
3. Simulate the electro pneumatic circuit diagram and check its correct functioning
4. Compile an equipment list
5. Carry out the pneumatic and electrical circuit assembly.
6. Check the circuit operation.
Filling of pots of paint.
1. Pressing of a pushbutton is to cause the pressing ram to advance and the slip-lid
to be pressed on.
2. Once the pushbutton is released, the pressing ram is to be returned into the
initial position.
A relay is a remotely controlled electromagnetically actuated switch with several
contacts.
The main components are:
Coil with core
Winding of coil
Contact set
Return spring
Amature
Terminal lugs
Exercise 3: Releasing a lid press
-describe the mode of operation of a relay
A relay passes on signals to a specified part of a circuit which may be a
switch or an actuator. Passing on signals may turn on/off the connected
electrical/pneumatic component.
One or several contacts can be switched by a relay coil. Relays with normally
closed, normally open or changeover contact(s) are used depending on the function
required.
Additional designs of the electromagnetically actuated switches are for instance a
remanence relay, the time relay with switch-one delay, the time relay with switch-off
delay and the contactor.
-describe the design and contact alignment of the relays show
1. This relay shows that you have two
normally open switches and two
normally closed switches. When there is
power running from A1 to A2, normally open switches will close and normally
closed switches will switch on
2.
This relay has 4 changeover contacts. This means that when power is running from
A1 to A2, switches will change from the left contact to the right.
-list the possible applications of relays in electrical or electropneumatical control
systems.
Relays can easily pass on signals from circuits to their pneumatic
counterparts.
Relays may also be used for continuous or a constant repetition of the
electropneumatic circuit’s operation.
Relays make possible the timing and delay of most actions done by
pneumatic parts connected to electronic controls.
-Design the pneumatic and electrical circuit diagrams for the lid press
Pneumatic Circuit Diagram:
Electrical Circuit Diagram:
Apart from the circuit diagram, comprehensive project documentation also requires an
equipment list
-compile the equipment list by entering the required equipment in the table below.
Quantity Description
1 double Acting cylinder
2 one-way flow valve
1 5/2-way solenoid valve
1 relay
1 solenoid valve
1 push-button
1 make-switch
In industrial practice, there are numerous different requirements with regard to a valve.
If a valve with all the required features is not available, it is often possible to use a valve
with a different number of ports. The table below lists a selection of directional control
valves frequently in use in industrial applications.
- Describe the valve types shown.
- Identify all solenoid valves that can be replaced by a 5/2 – way solenoid valve of
the type shown.
- If measures are required to convert the valve, describe these.
Symbol Description of valve
type
Replacement
possible
Necessary
Conversions
2/2 – way pilot
control solenoid
valve w/ manual
override, spring
return, NC
NO N/A
3/2-way solenoid valve
3/2 – way pilot
control solenoid
valve w/ manual
override, spring
return, NC
YES Seal work port 2
and 3
3/2-way solenoid valve
3/2 – way pilot
control solenoid
valve w/ manual
override, spring
return, NO
YES Seal work port 4
and 5
4/2 – way pilot
control solenoid
valve w/ manual
override, spring
return
YES Seal work port 1
Select a valve and explain the reason for your decision.
Valve: Pilot actuated, spring – return 3/2 – way solenoid valve w/ manual override
Reason: The solenoid valve chosen could be used as a substitute for lesser port valves,
such as the 4/2 and 3/2 way valves mentioned earlier. Choosing otherwise would mean
that should the user require a valve with more ports than the 3/2 way valve, an
additional purchase would have to be made, increasing costs.
Function Table
S1 S2 1M1 1V1
0 0 0 0
0 1 1 1
1 0 1 1
1 1 1 1
Symbol
TO BE PLACED
Pneumatic Circuit Diagram:
4 2
5
1
3
1S11M1K1
A1
A2
K3
1
2 4
K2
A1
A2
K1
3
4
K2
3
4
K3
A1
A2
K1
3
4
S1
3
4
S2
3
4
1 2 3 4
55 16
4
Electrical Circuit Diagram:
4 2
5
1
3
1S11M1K1
A1
A2
K3
1
2 4
K2
A1
A2
K1
3
4
K2
3
4
K3
A1
A2
K1
3
4
S1
3
4
S2
3
4
1 2 3 4
55 16
4
Equipment list:
1 5/2 way pilot control solenoid valve with manual override, spring return
1 one way flow control valve
1 compressor
3 relays
2 make – push buttons
Experiment 5: Realising a diverting device
Application 1
Valve type: valve with double solenoid
Reason: no need to hold button for it to stay in its position
Application 2
Valve type: valve with spring return
Reason: so it returns automatically after ejecting
It works similary to a 5/2 way valve but it is double electrically piloted (double solenoid).
It goes to the direction depending on which solenoid actuates it.
Answer:
v=Ir
24V/48ohms = 0.5 amps
The current consumption in 1M1 will be identical even if it uses 24V AC instead of 24V