095011 GB Fundamentals of Electropneumatics Collection of Transparencies 2 1 3 3 3 1 1 2 2
Oct 23, 2014
095011 GB
Fundamentals of
Electropneumatics
Collection of
Transparencies
2
1 3
33
11
22
Foreword
© Festo Didactic GmbH & Co. • Electropneumatics
The transparencies are designed from a didactical and methodological point of view.
For each transparency, there is a short accompanying text that provides the speaker
with a quick overview of the contents. More information you will find in the textbook
Electropneumatics.
� Physical fundamentals of electropneumatics
� Function and application of electropneumatic components
� Designation and drawing of electropneumatic symbols
� Drawing of pneumatic and electrical circuit diagrams in accordance with
standards
� Presentation of motion sequences and switching conditions
� Direct and indirect manual controls
� Direct and indirect direction-dependent controllers
� Logical AND/OR functions
� Pressure-dependent controls with pressure switches
� Troubleshooting in simple electropneumatic control systems
The text pages contain a complete picture of the transparency with some additional
explanations and items which the speaker can mark on the transparency during
instruction.
The advantages of this concept are:
� The speaker can add to the transparencies step-by-step during instruction.
� Instruction is livelier.
� The accompanying texts provided reduce preparation time.
Syllabus
New!
Electronic presentation
Contents
System Elements
Elements of a Control Chain __________________________________ Transparency 1
Pneumatic Components
Single-Acting Cylinder _______________________________________ Transparency 2
Double-Acting Cylinder ______________________________________ Transparency 3
Non-return, Flow Control and Pressure Control Valves_____________ Transparency 4
Pressure Regulating Valve____________________________________ Transparency 5
One-Way Flow Control Valve __________________________________ Transparency 6
Quick Exhaust Valve_________________________________________ Transparency 7
Electropneumatic Components
Conversion of Electrical Signals into Pneumatic Signals ___________ Transparency 8
Conversion of Pneumatic Signals into Electrical Signals ___________ Transparency 9
Switching Symbols for Valves ________________________________ Transparency 10
Directional Control Valves: Ports and Switching Positions_________ Transparency 11
Function Principle of a Solenoid Coil __________________________ Transparency 12
2/2-Way Solenoid Valve without Pilot Control __________________ Transparency 13
Solenoid Valves with Pilot Control ____________________________ Transparency 14
3/2-Way Single Solenoid Valve with Pilot Control _______________ Transparency 15
5/2-Way Single Solenoid Valve with Pilot Control _______________ Transparency 16
5/2-Way Double Solenoid Valve with Pilot Control_______________ Transparency 17
5/3-Way Solenoid Valve ____________________________________ Transparency 18
Electrical Components
Power Supply Units ________________________________________ Transparency 19
Switching Contacts and Types of Actuation_____________________ Transparency 20
Types of Actuation of Switching Elements ______________________ Transparency 21
Switching Symbols for Solenoid Coils and Relays________________ Transparency 22
The Relay ________________________________________________ Transparency 23
Magnetic Proximity Switches (Reed Switches) __________________ Transparency 24
Electrical Output Devices____________________________________ Transparency 25
Logic Functions
The AND Logic Function _____________________________________ Transparency 26
The OR Logic Function ______________________________________ Transparency 27
Contents
Electropneumatic Controller
Control Chain _____________________________________________ Transparency 28
Direct Actuation of a Single-Acting Cylinder ____________________ Transparency 29
Indirect Actuation of a Double-Acting Cylinder __________________ Transparency 30
Electrical Memory Circuit – Dominant Set ______________________ Transparency 31
Electrical Memory Circuit – Dominant Reset ____________________ Transparency 32
Electropneumatic Memory Circuit with Double Solenoid Valve _____ Transparency 33
Stroke-Dependent Control___________________________________ Transparency 34
Pressure-Dependent Control_________________________________ Transparency 35
Circuit Diagram Design
The Electropneumatic Circuit Diagram _________________________ Transparency 36
Circuit Diagram Structure ___________________________________ Transparency 37
Displacement-Step Diagram _________________________________ Transparency 38
Terminal Connection Diagram
Terminal Connection Diagram ________________________________ Transparency 39
Checklist for the Terminal Connection Diagram__________________ Transparency 40
Special Features with the Connection of Solenoid Coils
Protective Circuits for Inductive Loads _________________________ Transparency 41
Programmable Logic Controllers
Alterable Controls__________________________________________ Transparency 42
1
Elements of a Control Chain
The principle of the control chain is used for the preparation of the circuit diagram.
Every element of a control chain has a certain task to perform in the processing and
further transmission of signals.
This structuring of a system into functional blocks has proven itself in the following
tasks:
� Arrangement of the elements in the circuit diagram
� Definition of the nominal sizes, nominal current and nominal voltage of
components
� Set-up and commissioning of the controller
� Identification of the components for maintenance work
–
–
–
Electric motors
Solenoids
Linear motors
–
–
–
Power contactors
Power transistors
Power thyristors
–
–
–
–
–
Switches
Push button
actuators
Limit switches
Program
module
Sensors
Electrics/ Electronics
–
–
–
–
–
–
Switches
Push button actuators
Limit switches
Program module
Sensors
Indicators/generators
–
–
–
Contactors
Relays
Electronic modules
Pneumatics/ Hydraulics
– Directional
control valves
–
–
–
Directional
control valves
Isolating valves
Pressure valves
Working elements
Control elements
Processingelements
(Control elements)
Input elements
–
–
–
Cylinders
Motors
Components
TP 201, 01Transparency
Elements of a Control Chain
Electrics/Electronics
–
–
–
Power contactors
Power transistors
Power thyristors
–
–
–
–
–
–
Switches
Push button actuators
Limit switches
Program module
Sensors
Indicators/generators
–
–
–
Contactors
Relays
Electronic modules
–
–
–
Electric motors
Solenoids
Linear motors
Pneumatics/Hydraulics
– Directional
control valves
–
–
–
Directional
control valves
Isolating valves
Pressure valves
Working elements
Control elements
Processingelements
(Control elements)
Input elements
–
–
–
Cylinders
Motors
Components
–
–
–
–
–
Switches
Push button
actuators
Limit switches
Program
module
Sensors
2
Single-Acting Cylinder
Compressed air is applied to only one side of the single-acting cylinder.
The piston rod side of the cylinder is vented to atmosphere.
Single-acting cylinders can perform work in only in the advance direction of travel.
The piston rod is driven inwards by the force of a built-in spring or by external forces.
Piston
Reset spring
Piston rod
Bearing capEnd cap
Exhaust portSealing ring
Supply port Cylinder barrel
TP 201, Transparency 02
Single-Acting Cylinder
3
Double-Acting Cylinder
The double-acting cylinder is actuated in both directions with compressed air.
It can perform work in both directions of movement.
The force transmitted to the piston rod is greater during the advance stroke than
during the return stroke.
End cap
Piston Piston rod
Bearing cap
Scraper ring
Cylinder barrel
TP 201, Transparency 03
Double-Acting Cylinder
4
Non-return, Flow Control and Pressure Control Valves
Non-return valves block the flow in one direction and release it in the opposite
direction. A distinction is made between:
� Non-return valves
� Shuttle valves (OR)
� Dual pressure valves (AND)
� One-way flow control valves
� Quick exhaust valves
Pressure control valves influence the pressure or are controlled through the size of
the pressure. A distinction is made between:
� Pressure regulating valves
� Pressure relief valves
� Pressure sequence valves
Sloping arrow – the valve is adjustable
Non-return valves
Flow control valve
Pressure control
valve
– Non-return valve (check valve)
– Flow control valve (throttle valve), adjustable
– Non-return valve, spring-loaded
– Shuttle valve (OR function)
– Quick exhaust valve
– One-way flow control valve
– Adjustable pressure regulating valve without relief port
– Adjustable pressure regulating valve with relief port
– Pressure sequence valve with external supply line
– Pressure-relief valve
– Pressure sequence valve-combination
– Dual pressure valve (AND function)
12
3
2
2
2
2
1
1
1
1
3
12
2
1
TP 201, Transparency 04
Non-return, Flow Control and Pressure Control Valves
Non-return valves
Flow control valve
Pressure control
valve
– Non-return valve (check valve)
– Flow control valve (throttle valve),adjustable
– Non-return valve, spring-loaded
– Shuttle valve (OR function)
– Quick exhaust valve
– One-way flow control valve
12
3
– Adjustable pressure regulating valvewithout relief port
– Adjustable pressure regulating valvewith relief port
– Pressure sequence valvewith external supply line
– Pressure-relief valve
2
2
2
2
1
1
1
1
– Pressure sequencevalve-combination
3
12
2
1
– Dual pressure valve (AND function)
5
Pressure Regulating Valve
Pressure regulators have the function of keeping the output pressure mainly
constant, independent of variations in the input pressure and the air consumption.
If the pressure rises at the outlet, the diaphragm moves against the spring force and
the flow cross-section at the valve seat is reduced or closed.
If the pressure drops at the outlet, the spring presses against the diaphragm and the
passage cross-section at the valve seat is enlarged or opened.
The output pressure is adjustable.
The input pressure must be higher than the output pressure.
P1 P2 P1 P2
1
3
2
P1 P2
TP 201, Transparency 05
Pressure Regulating Valve
1
3
2
P1 P2
6
One-Way Flow Control Valve
The check element blocks the flow of air in one direction, so that it flows across an
adjustable throttle in this direction.
The air flow from the opposite direction lifts the seal of the check element from the
seat. The compressed air can flow almost unrestricted in this direction.
The valve should be installed as close as possible to the cylinder.
4
5
2
1Y1 1Y2
31
1A
1V2 1V3
1V1
TP 201, Transparency 06
One-Way Flow Control Valve
4
5
2
1Y1 1Y2
31
1A
1V2 1V3
1V1
7
Quick Exhaust Valve
Quick exhaust valves are used to achieve the maximum advance and retract speed
of pneumatic cylinders.
To increase the effectiveness of the valve, it should be mounted directly on the
cylinder or in the immediate vicinity of the supply or exhaust ports of the cylinder.
2
3
2
1Y1
1 3
1A
1
1V2
1V1 1V1
2
3
1Y2
13
1A
1
1V2
4
5
2
2
1
3
2
1
3
�
�
TP 201, Transparency 07
Quick Exhaust Valve
2
3
2
1Y11 3
1A
1
1V2
1V1 1V1
2
3
1Y2
13
1A
1
1V2
4
5
2
2
1 3
2
1
3
2
1
3
8
Conversion of Electrical Signals into Pneumatic Signals
If control systems are using compressed air and electricity as working mediums,
converter systems must be used.
Solenoid valves convert electrical signals into pneumatic signals.
Solenoid valves consist of:
� A pneumatic valve
� A coil which switches the valve
2
1 3
unactuated actuated
33
11
22
2
1 3
Conversion of Electrical Signals into Pneumatic Signals
unactuated actuated
33
11
22
TP 201, Transparency 08
9
Conversion of Pneumatic Signals into Electrical Signals
The PE converter is actuated with compressed air. When the pressure reaches a
preset value, an electric signal is generated.
The pressure of a pneumatic signal works against an adjustable spring.
If the pressure working against the diaphragm overcomes the spring force, a stem
actuates an electrical switch contact.
The electrical switching element can be normally closed, normally open or
changeover contact.
14
1414
unactuatedactuated
TP 201, Transparency 09
Conversion of Pneumatic Signals into Electrical Signals
14
1414
unactuatedactuated
10
Switching Symbols for Valves
Pneumatic components are normally shown in the deenergized condition in circuit
diagrams.
Valve switching positions are represented by a square.
The number of squares corresponds to the number of switching positions.
Functions and modes of operation are drawn inside the square:
� Lines indicate the flow paths.
� Arrows indicate the flow direction.
� Closed ports are represented by two lines drawn at right angles to one another.
The connecting lines are drawn outside on the square.
The valve switching position is shown by a square.
The number of squares corresponds to the number of switching positions.
Lines indicate the flow paths, arrows indicate the direction of flow.
Closed ports are shown by two lines drawn at right angles to one another.
The connecting lines for supply and exhaust air are drawn outside the square.
TP 201, Transparency 10
Switching Symbols for Valves
The valve switching position is shown by a square.
The number of squares corresponds to the number of switching positions.
Lines indicate the flow paths, arrows indicate the direction of flow.
Closed ports are shown by two lines drawn at right angles to one another.
The connecting lines for supply and exhaust air are drawn outside the square.
11
Directional Control Valves: Ports and Switching Positions
Information about the type of valve can be established from the following features:
� Number of ports
� Number of switching positions
� Port numbering
The following applies to the numbering of the ports:
� Air supply port 1
� Exhaust ports 3, 5
� Working or outlet ports 2, 4
2/2-way valve, normally open position
4/2-way valve flow from 1 2 and from 4 3� �
5/2-way valve flow from 1 2 and from 4 5� �
5/3-way valve, mid-position closed
3/2-way valve, normally closed position
3/2-way valve, normally open position
Number of switching positions
Number of ports
4
4
4
2
2
2
2
2
2
3
3
3
3
3
1
1
1
1
1
1
5
5
Directional Control Valves:Ports and Switching Positions
2/2-way valve, normally open position
4/2-way valveflow from 1 2 and from 4 3� �
5/2-way valveflow from 1 2 and from 4 5� �
5/3-way valve, mid-position closed
3/2-way valve, normally closed position
3/2-way valve, normally open position
Number of switching positions
Number of ports
4
4
4
2
2
2
2
2
2
3
3
3
3
3
1
1
1
1
1
1
5
5
TP 201, Transparency 11
12
Function Principle of a Solenoid Coil
When an electric current flows through a coil, a magnetic field is generated.
The following applies to the strength of the magnetic field:
� Increasing the number of windings increases the field.
� Increasing the strength of the current increases the field.
� Lengthening the coil reduces the field.
A soft iron core (armature) is drawn into a coil through which a current is flowing.
Coil winding
Soft iron core
TP 201, Transparency 12
Function Principle of a Solenoid Coil
Coil winding
Soft iron core
13
2/2-Way Solenoid Valve without Pilot Control
Normally-closed position, spring return
Solenoid coil deenergized
� Port 1 is blocked.
� Port 2 is blocked.
� Exhausting is not possible.
Solenoid coil energized
� The armature is raised.
� Compressed air flows from port 1 to port 2.
2
1
1 12 2
TP 201, Transparency 13
2/2-Way Solenoid Valve without Pilot Control2
1
1 12 2
14
Solenoid Valves with Pilot Control
Solenoid valves with pilot control consist of:
� An electromagnetically-actuated pilot control valve.
� A pneumatically-actuated main valve.
In comparison with solenoid valves without a pilot control, solenoid valves with a
pilot control are distinguished by:
� Lower force required to actuate the armature.
� Smaller dimensions of the coil head.
� Lower power consumption.
� Less heat generated.
An electrical signal isapplied to the solenoidcoil
The solenoid coilactuates the pilotcontrol valve
The pilot controlactuates the valve
TP 201, Transparency 14
Solenoid Valves with Pilot Control
An electrical signal isapplied to the solenoidcoil
15
3/2-Way Single Solenoid Valve with Pilot Control
Normally-closed position, spring return, manual override
Solenoid coil deenergized
� Port 1 is blocked.
� Port 2 is vented to port 3.
� The pilot control channel is blocked by the armature seal on the valve side.
� The space above the valve piston is vented through the armature guide tube.
Solenoid coil energized
� The armature is lifted and the armature seal on the coil side blocks the vent hole
in the armature guide tube, while the armature seal on the valve side opens the
pilot control channel.
� Compressed air from port 1 flows through the pilot control channel and actuates
the valve piston.
� Port 3 is blocked.
� Compressed air flows from port 1 to port 2.
2
1 3
33
11
22
2
1 3
3/2-Way Single Solenoid Valve with Pilot Control
33
11
22
TP 201, Transparency 15
16
5/2-Way Single Solenoid Valve with Pilot Control
Spring returned, manual override
Solenoid coil deenergized
� Compressed air flows from port 1 to 2.
� Port 4 is vented to 5.
� Port 3 is blocked.
� The pilot control channel is blocked.
� The space above the valve piston is vented through the armature guide tube.
Solenoid coil energized
� The armature is lifted and the armature seal on the coil side blocks the vent in
the armature guide tube, while the armature seal on the valve side opens the
pilot control channel.
� Compressed air from port 1 flows through the pilot control channel and actuates
the valve piston.
� Port 5 is blocked.
� Compressed air flows from port 1 to port 4.
� Port 2 is vented to port 3.
4
4
2
2
1
1
14
14
3
3
5
5
84
84
3
3
2
2
1
1
4
4
5
5
84
84
14
14
TP 201, Transparency 16
5/2-Way Single Solenoid Valve with Pilot Control
4
4
2
2
1
1
14
14
3
3
5
5
84
84
3
3
2
2
1
1
4
4
5
5
84
84
14
14
17
5/2-Way Double Solenoid Valve with Pilot Control
Manual override
Solenoid coil Y1 energized, solenoid coil Y2 deenergized
� The valve switches over.
� Port 3 is blocked.
� Compressed air flows from Port 1 to Port 2.
� Port 4 is vented to Port 5.
Both solenoid coils deenergized
� The valve retains its previous switching position.
Solenoid coil Y2 energized, solenoid coil Y1 deenergized
� The valve switches over.
� Port 5 is blocked.
� Compressed air flows from port 1 to port 4.
� Port 2 is vented to port 3.
4
4
2
2
1
1
14
14
12
12
3
3
5
5
84
84
82
82
3214584 82
14 12
3214584 82
14 12
TP 201, Transparency 17
5/2-Way Double Solenoid Valve with Pilot Control
4
4
2
2
1
1
14
14
12
12
3
3
5
5
84
84
82
82
3214584 82
14 12
3214584 82
14 12
18
5/3-Way Solenoid Valve
The three switching positions of an electrically-actuated pilot-controlled
5/3-way valve:
1. In the normal position, the solenoid coils are deenergized and the piston is
centered in its mid-position by the two springs. Ports 2 and 3 as well as 4 and 5
are connected. Port 1 is blocked.
2. If current is applied to the lefthand solenoid coil, the piston moves to the right.
Ports 1 and 4 as well as 2 and 3 are connected with each other.
3. If current flows through the righthand solenoid coil, the piston moves to the left.
In this position, Ports 1 and 2 as well as 4 and 5 are connected.
Each of the two actuated switching positions is held as long as current flows through
the corresponding solenoid coil. If the flow of current is interrupted, the piston
switches back to the mid-position.
4
4
2
2
5
5
3
3
1
1
12
12
14
14
84
84
82
82
4 2
5 31
1214
84 82
3
3
3
2
2
2
1
1
1
4
4
4
5
5
5
84
84
84
82
82
82
14
14
14
12
12
12
TP 201, Transparency 18
4
4
2
2
5
5
3
3
1
1
14
14
12
12
14
14
84
84
82
82
4 2
5 31
5/3-Way Solenoid Valve
14 1214
84 82
3
3
3
2
2
2
1
1
1
4
4
4
5
5
5
84
84
84
82
82
82
14
14
14
12
12
12
19
Power Supply Units
It is necessary to distinguish between an alternating current and a direct current
power supply.
� Is supplied from the mains
� 3-phase or single-phase form
� Sinusoidal-shaped voltage of fixed frequency
� Relatively constant amplitude
� Voltage change through transformers
� Is supplied by power supply devices
Modules of direct current power supply devices
� Mains transformer
� Rectifier
� Stabilization
Batteries and rechargeable batteries
� Used for buffering in case of mains failure.
� Used in portable devices.
+
Transformer StabilizerRectifier
Power supply unit
Alternating current Direct current Battery
Alternating current
Direct current
TP 201, Transparency 19
Power Supply Units
Transformer StabilizerRectifier
Power supply unit
Alternating current Direct current Battery
+-
20
Switching Contacts and Types of Actuation
The following switch contact designs are used as input and processing elements:
� Normally-open contact
� Normally-closed contact
� Changeover contact
Types of actuation for switching elements are:
� Manual
� Mechanical
� Relay
� Magnet field
Normally-opencontacts
Changeoverswitch
Mechanically connectedcontacts
Rotary switch withnormally open contactsmanually actuatedby turning
Push-button withnormally open contactsmanually actuatedby pushing
Limit switch with normally openor normally closed contacts,mechanically actuated
Normally-closedcontacts
TP 201, Transparency 20
Switching Contacts and Types of Actuation
Normally-opencontacts
Changeoverswitch
Mechanically connectedcontacts
Rotary switch withnormally open contactsmanually actuatedby turning
Push-button withnormally open contactsmanually actuatedby pushing
Limit switch with normally openor normally closed contacts,mechanically actuated
Normally-closedcontacts
21
Types of Actuation of Switching Elements
Frequently used types of actuation are
� Pushbuttons
� Roller levers
� Roller lever with idle return
Two types of actuation are shown
� Pushbutton, as changeover switch
� Latching rocker switch, as normally-open contact
Identifying letters in electrical circuit diagrams: S (S1, S2, ...)
Connection(normally-closed contact)
Connection(normally-open contact)
Switching element
Type of actuation(push-button)
4
3
2
1
4
3
4 4
3
TP 201, Transparency 21
Types of Actuation of Switching Elements
4
3
2
1
4
3
4 4
3
Connection(normally-closed contact)
Connection(normally-open contact)
Switching element
Type of actuation(push-button)
22
Switching Symbols for Solenoid Coils and Relays
In electropneumatics, the solenoid coil is the element that switches the valves.
Identifying letters in electrical circuit diagrams: Y (Y1, Y2, ...)
A relay switches 1, 2 or more contacts. The relay can also be a time or temperature-
controlled element.
Identifying letters in electrical circuit diagrams: K (K1, K2, ...)
Y1
K1
Electro-magneticallyactuated on both sides
Electro-magneticallyactuated,with pilot control
Contactor or relay with3 normally open contactsand 1 normally closed contact
Electro-magneticallyactuated on one side,with spring return
Representation inelectrical circuitdiagrams
TP 201, Transparency 22
Switching Symbols for Solenoid Coils and Relays
Electro-magneticallyactuated on both sides
Electro-magneticallyactuated,with pilot control
Contactor or relay with3 normally open contactsand 1 normally closed contact
Electro-magneticallyactuated on one side,with spring return
Representation inelectrical circuitdiagrams
K1
Y1
23
The Relay
In practice, the construction of a relay can be very different, but the function is
nevertheless the same in principle:
� When a voltage is applied to the relay coil through contacts A1 and A2, an
electric current flows through the windings. A magnetic field is built up and pulls
the armature against the core of the coil.
� Switch contact 1 is connected with switch contact 4.
� After removing the voltage, the armature is brought back into its initial position
by a spring.
� Switching contact 1 is connected with switching contact 2.
A relay can have multiple switching contacts which can be actuated simultaneously.
There are the following types, for example:
� Polarised relay
� Current impulse relay
� Time relay
� Thermal relay
124A1 A2
A1
A2
221412 24
11 21
Coil core
Insulation
Contact
Return spring
Relay coil
Armature
TP 201, Transparency 23
The Relay
Coil core
Insulation
Contact
Return spring
Relay coil
Armature
124A1 A2
A1
A2
221412 24
11 21
24
Magnetic Proximity Switches (Reed Switches)
Reed switches are actuated through a magnetic field. In industrial applications, most
reed switches are used with LED displays.
The illustration shows a three-wire reed switch. It has three connections:
� One connection for the positive power supply
� One connection for the negative power supply
� One signal or switch output
The reed switch is attached directly to the body of a cylinder. It is actuated by a
magnetic ring on the cylinder piston.
When the magnetic ring moves past the reed switch, the switching contacts are
closed as a result of the magnetic field and thus provide an output signal.
Identifying letters in electrical circuit diagrams: B (B1, B2, ...)
BN
BK
BU
+24V
0V
TP 201, Transparency 24
Magnetic Proximity Sensors (Reed Switches)
BN
BK
BU
+24V
0V
25
Electrical Output Devices
Supply acoustic signals:
� For example, horns, sirens
� Identifying letters in electrical circuit diagrams: H (H1, H2, ...)
Supply optical signals:
� For example, lamps, LEDs
� Identifying letters in electrical circuit diagrams: H (H1, H2, ...)
Do work:
� For example, electric motors
� Identifying letters in electrical circuit diagrams: M (M1, M2, ...)
M
Signalling device
Motors
Audible indicator:
Illuminatingindicators:
Horn
DC motor
Lamp Light emitting diode (LED)
Siren Bell
Signalling device
Motors
TP 201, Transparency 25
Electrical Output Devices
Audible indicator:
Illuminatingindicators:
Horn
DC motor
Lamp Light emitting diode (LED)
Siren Bell
M
26
The AND Logic Function
The AND logic function consists of at least two switching elements connected in
series:
� The AND logic function can have two or more inputs. A combination of switches
and sensors may be involved.
� The function is represented through a logic symbol with two inputs and one
output.
� Both input signals must be present to switch the output.
&
+24V
0V
S2
H1
S1
1
Output(lamp H1)Input 2
(S2)
Input 1(S1)
TP 201, Transparency 26
The AND Logic Function
OutputInput 2
Input 1&
+24V1
0V
S2
H1
S1
27
The OR Logic Function
The OR logic function consists of at least two switching elements connected in
parallel:
� The OR logic function can have two or more inputs. A combination of switches
and sensors may be involved.
� The function is represented through a logic symbol with two inputs and one
output.
� Only one input signal needs to be present to switch the output.
�1
+24V
0V
H1
S1 S2
1 2
Output(lamp H1)Input 2
(S2)
Input 1(S1)
TP 201, Transparency 27
The OR Logic Function
OutputInput 2
Input 1�1
+24V
0V
H1
S1 S2
1 2
28
Control Chain
The structure of the control chain supports:
� The allocation of components with comparable functions to a group of elements.
� The avoidance of lines crossing each other in pneumatic and electrical circuit
diagrams.
� The preparation of clearly structured and uniformly designed circuit diagrams.
The principle of the control chain should be understood as being only a guideline.
The signal flow of the control system defines the structure of the control chain:
� In the pneumatic circuit diagram, the signal flow is represented from bottom to
top.
� In the electrical circuit diagram, the signal flow is represented from top to
bottom.
+24V
Signalinput
Sig
na
l fl
ow
Sig
na
l fl
ow
Signalprocessing
Signaloutput
0V
S1
S2
K1K1
1Y1
2
1 2
4
5
2
1Y1
31
1A
1V1
TP 201, Transparency 28
Control Chain
+24V
Signal input
Signal processing
Signal output
0V
S1
S2
K1K1
1Y1
2
1 2
4
5
2
1Y1
31
1A
1V1
29
Direct Actuation of a Single-Acting Cylinder
After actuating S1, current flows through the coil 1Y1, which switches the valve 1.1.
Compressed air flows from port 1 to port 2, and the piston rod advances.
If S1 is no longer actuated, there is no current through coil 1Y1. Valve 1.1 switches
back into the initial position.
The cylinder is vented through port 3 of valve 1.1, and the piston rod retracts.
1Y1
2
1Y1
1A
1V1
+24V
0V
S1
1
1 3
TP 201, Transparency 29
Direct Actuation of a Single-Acting Cylinder
1Y1
2
1Y1
1A
1V1
+24V
0V
S1
1
1 3
30
Indirect Actuation of a Double-Acting Cylinder
The use of indirect actuation depends upon:
� The force which is required for the actuation of the positioner
� The complexity of the circuit
� The switching power of the contacts
� Whether or not the system is remote controlled
K1 1Y1
1A
+24V
0V
S1 K1
1 2
4
5
2
1Y1
3
13
A1
A2
13
14 14
1
1V1
TP 201, Transparency 30
Indirect Actuation of a Double-Acting Cylinder
1Y1
1A+24V
0V
S1
1 2
4
5
2
1Y1
3
13
14
1
1V1
31
Electrical Memory Circuit – Dominant Set
A relay can be held in the switched condition if a holding current path is switched in
parallel to the ON pushbutton through an internal normally-open contact in the
relay.
An OFF pushbutton must be built into the memory circuit. The installed position of
the OFF pushbutton determines the function of the memory circuit.
A memory circuit in which a pushbutton (S2, normally-closed) is connected in series
with a relay holding contact (normally-open) is a dominating set memory circuit.
In this dominating set memory circuit, the pushbutton S1 dominates the pushbutton
S2.
If S1 and S2 are pressed simultaneously, current flows through the relay coil K1.
+24V
0V
S1
S2
K1 K1
2
3
1 2 3
13 23
14 24
K1 H1
© TP 201, Transparency 31
Electrical Memory Circuit – Dominant Set
+24V
0V
S1
S2
K1 K1
K1 H1
23
1 2 3
13 23
14 24
32
Electrical Memory Circuit – Dominant Reset
A relay can be held in the switched condition if a holding current path is switched in
parallel to the ON pushbutton to the relay coil through an internal normally-open
contact in the relay.
An OFF pushbutton must be built into the memory circuit. The installed position of
the OFF pushbutton determines the function of the memory circuit.
A memory circuit in which a pushbutton (S1, normally-open) and a relay holding
contact (normally-open) are connected in parallel and then in series with a
pushbutton (S2, normally-closed) is a dominating reset memory circuit.
In this dominating reset memory circuit, the pushbutton S2 dominates the
pushbutton S1.
If S1 and S2 are pressed simultaneously, no current flows through the relay coil K1.
+24V
0V
S1
S2
K1 K1
2
3
1 2 3
13 23
14 24
K1 H1
© TP 201, Transparency 32
Electrical Memory Circuit – Dominant Reset
+24V
0V
S1
S2
K1 K1
23
1 2 3
13 23
14 24
K1 H1
33
Electropneumatic Memory Circuit with Double Solenoid Valve
Double solenoid valves are also called bistable valves or memory valves:
� The valve illustrated is actuated by two solenoid coils.
� The valve retains the switched position brought about through energising one of
the coils, even when the signal to switch the valve is cancelled.
� The switched position is reversed only when a signal is applied to the opposite
coil or a manual override is operated.
� To reverse the switched position, a signal only needs to be applied to one coil.
1A 1S2
4
5
2
1Y1 1Y2
31
1V1
1Y1 1Y2
+24V
0V
S1
1 32 4
1S2 K1 K2
K1 K2
3 4
TP 201, Transparency 33
Electropneumatic Memory Circuit with Double Solenoid Valve
1A 1S2
4
5
2
1Y1 1Y2
31
1V1
1Y1 1Y2
+24V
0V
S1
1 32 4
1S2 K1 K2
K1 K2
3 4
34
Stroke-Dependent Control
Limit switches with roller lever actuation are frequently used to check the position of
pneumatic actuators in simple circuits.
The use of limit sensors in a control depends upon the required accuracy of the
sensor.
Decisive factors are:
� The reliability
� The safety
� The complexity of the circuit
1A 1S21S1
4
5
2
1Y1 1Y2
31
1V1
1Y1 1Y2
+24V
0V
S1
1S1
1 32 4
1S2 K1 K2
K1 K2
3 4
TP 201, Transparency 34
Stroke-Dependent Control
1A 1S21S1
4
5
2
1Y1 1Y2
31
1V1
1Y1 1Y2
+24V
0V
S1
1S1
1 32 4
1S2 K1 K2
K1 K2
3 4
35
Pressure-Dependent Control
A pneumatic-electric signal converter measures the air pressure in the supply line of
cylinder 1A and compares it with a preset value.
As soon as this value is reached, the signal converter generates an electrical signal.
1A
4
5
2
p
1Y1
1B1
1Y2
31
1V1
1Y1 1Y2
+24V
0V
S1
1 6 7
K1 K2
K3
K1
5 6 6
1B2
1B2 1B1
p
2 43 5
K2 K3
TP 201, Transparency 35
Pressure-Dependent Control
1A
4
5
2
p
1Y1
1B1
1Y2
31
1V1
1Y1 1Y2
+24V
0V
S1
1 6 7
K1 K2
K3
K1
5 6 6
1B2
1B2 1B1
p
2 43 5
K2 K3
36
The Electropneumatic Circuit Diagram
The pneumatic and electrical parts of an electropneumatic circuit diagram are
prepared separately, but their contents are closely related.
In the pneumatic part, signal flow is presented from bottom to top.
In the electrical part, signal flow is presented from top to bottom.
In the electrical circuit diagram, the current paths are numbered consecutively from
left to right.
The common circuit diagram elements form the interfaces between the pneumatic
and the electrical circuits. In this case, they are the coils 1Y1 and 2Y1, as well as the
limit sensors 1B1, 1B2, 2S1 and 2S2.
44
55
22
2Y11Y1
3311
2A1A
2V11V1
2S21B21B1
2S1
1Y1 2Y1
+24V
0V
Start 2S1
K6 K5
1B1 1B2
1 3 5 6 8 10 12 13117 92 4
2S2K3 K4 K5 K3 K4K2
K1
K3 K4 K5
K1 K2 K3 K4 K5 K6
5 7 6
7
12
8
9
13
10
11
13 5
TP 201, Transparency 36
The Electropneumatic Circuit Diagram
44
55
22
2Y11Y1
3311
2A1A
2V11V1
2S21B21B1
2S1
1Y1 2Y1
+24V
0V
Start 2S1
K6 K5
1B1 1B2
1 3 5 6 8 10 12 13117 92 4
2S2K3 K4 K5 K3 K4K2
K1
K3 K4 K5
K1 K2 K3 K4 K5 K6
5 7 67
12
89
13
1011
13 5
37
Circuit Diagram Structure
The electropneumatic circuit diagram consists of two parts:
� Pneumatic
� Electrical
� The arrangement of the components follows the signal flow accordingly from
bottom to top.
� Cylinders and valves are drawn horizontally.
� The outward travel motion of cylinders should be from left to right.
� The arrangement of the components follows the signal flow accordingly from top
to bottom.
� The electrical circuit diagram can be subdivided into a control part and a power
part.
1A
1V2
0Z
1S2
4
5
2
1Y1 1Y2
31
1V1
1Y1 1Y2
+24V
Control section Power section
0V
S1
K2
1 32 4
1S2 K1 K2
K1 K2
3 4
Pneumatic
Electrical
TP 201, Transparency 37
Circuit Diagram Structure
1A
1V2
0Z
1S2
4
5
2
1Y1 1Y2
31
1V1
1Y1 1Y2
+24V
0V
S1
K2
1 32 4
1S2 K1 K2
K1 K2
3 4
38
Displacement-Step Diagram
In a displacement-step diagram, the motion sequences of an actuator in a control
system are presented graphically:
� Movements of the cylinder within a step are represented by a line moving
diagonally upwards (advancing) or downwards (retracting).
� Horizontal lines represent the position of the cylinder in the advanced or
retracted end position.
� If the movements of several actuators are to be represented, they are arranged
under each other for every individual step.
� This arrangement clarifies the relationship between the movements of the
individual actuators in every step.
1
0
1
0
1
Step
2 3 4 5=1
1A
2A
TP 201, Transparency 38
Displacement-Step Diagram
1
0
1
0
1
Step
2 3 4 5=1
1A
2A
39
Terminal Connection Diagram
The terminal connection diagram shows the physical implementation of the current
circuit.
The identifications used in the circuit diagram are used in the terminal connection
diagram.
The terminal points and the cables are numbered. This facilitates the setting-up of
the controller as well as troubleshooting and maintenance.
X1-1 X1-2
3 1
11 11
21
4 2
14 14
24
X1-3 X1-4
X1-9 X1-12 X1-14
X1
X1 14
15
14
20
13
19
12
18
11
17
10
16
9
8
7
6
5
4
3
2
1
1Y1
K1 114
3
+24V
K2 21
X1 110V
K1 A2
K2 A2
X1 17
1B1 X1 1+
1B1
1S2
K1
K2
A1
24
1B1
1S2
X1
X1
5
8
1Y1
X1 2S1
X1 31
S1
K2 112
9
12X1
4
5
2
1Y1
31
1A
1V1
1S21B1
1Y1
+24V
0V
S1 1S21B1
1 3 4 52
K1 K2
K2
K1 K2
3 4
5
X1-11
X1-16
X1-10
A1 A1
A2 A2
X1-5 X1-8X1-6 X1-7
X1-13 X1-15
X1-17
Connection
code
Component
code
Co
mp
on
en
tco
de
Connection
code
Term
ina
l n
o.
X1
Jum
pe
r
Targ
et
Targ
et
Machine Control cabinet
TP 201, Transparency 39
Terminal Connection Diagram
X1-1 X1-2
3 1
11 11
21
4 2
14 14
24
X1-3 X1-4
X1-9 X1-12 X1-14
Co
nn
ect
ion
cod
e
X1
X1 14
15
14
20
13
19
12
18
11
17
10
16
9
8
7
6
5
4
3
2
1
1Y1
K1 114
-
3
+24V
Co
mp
on
en
tco
de
Co
mp
on
en
tco
de
Co
nn
ect
ion
cod
e
Term
ina
ln
o.
X1
Jum
pe
r
Targ
et
Targ
et
K2 21
X1 110V
K1 A2
K2 A2
X1 17
1B1 X1 1+
1B1
1S2
K1
K2
A1
24
1B1
1S2
X1
X1
5
8
1Y1
X1 2S1
X1 31
S1
K2 112
9
12X1
Machine Control cabinet
4
5
2
1Y1
31
1A
1V1
1S21B1
1Y1
+24V
0V
S1 1S21B1
1 3 4 52
K1 K2
K2
K1 K2
3 45
X1-11
X1-16
X1-10
A1 A1
A2 A2
X1-5 X1-8X1-6 X1-7
X1-13 X1-15
X1-17
40
Checklist for the Terminal Connection Diagram
In the preparation of a terminal connection diagram, the structure of the control
should be checked once again:
� Is every current path connected to the positive +24V bus bar through a terminal?
� Is every current path connected to the negative 0 V bus bar through a terminal?
� Are all external components, such as switches, sensors and valve coils connected
with one terminal per connection to the current circuit?
� Are all connections to the +24 V and 0 V shown in the terminal connection
diagram?
� Are all external components included in the terminal connection diagram
provided with their connection identifications?
� Check all current paths systematically and complete the terminal connection
diagram.
� Note that not all connections – such as the relay contacts, for example – must be
included in the terminal connection diagram.
Enter all external components with thedesignation of the connection in theterminal connection diagram.
Systematically check all current pathsand complete the wiring diagram.
Not all of the connections have to beentered in the wiring diagram(e.g. relay connections are exempt).
Note:
� �
�
�
�
Each current path must be connectedto the positive +24 V rail via a terminal.
Each current path must be connectedto the negative 0 V rail via a terminal.
External components, such as switches,sensors and solenoids are eachconnected via one terminal per unit.
Identify the connection point for +24 Vand 0 V in the wiring diagram.
TP 201, Transparency 40
Checklist for the Terminal Connection Diagram
Each current path must be connectedto the positive +24 V rail via a terminal.
Each current path must be connectedto the negative 0 V rail via a terminal.
External components, such as switches,sensors and solenoids are eachconnected via one terminal per unit.
Identify the connection point for +24 Vand 0 V in the wiring diagram.
Enter all external components with thedesignation of the connection in theterminal connection diagram.
Systematically check all current pathsand complete the wiring diagram.
Not all of the connections have to beentered in the wiring diagram(e.g. relay connections are exempt).
Note:
� �
�
�
�
�
�
41
Protective Circuits for Inductive Loads
If the current flowing to an inductive load, for example, a solenoid coil, is
interrupted, the magnetic field collapses.
A high induction voltage can be generated which can have the following effects:
� Damage to the coil insulation
� Burning of contacts
This can be avoided through protective circuits using diodes.
I1
I = 01
I = IM 1
IM
I = 0D
I = ID M
+24V +24V
0V 0V
TP 201, Transparency 41
Protective Circuits for Inductive Loads
I1 I = 01
I = IM 1 IMI = 0D I = ID M
+24V +24V0V 0V
42
Alterable Controls
Relay-controlled systems are hard wired. The relay control can be replaced in whole
or in part by a programmable controller.
The structure of a system that is controlled via a programmable logic controller (PLC)
is similar to that of a relay-controlled system. Both systems can be subdivided as
follows:
� Signal input
� Signal processing
� Signal output
The signal processing part is the part that can be hard wired or freely programmable.
Switch
Inputs
Signalinput
Signaloutput
Signal processing
Relays Contacts
Outputs
Program:
WHEN
THENOTHERWISE
WHEN
THENOTHERWISE
E0.1
E0.2
A0.1
A0.1
E0.3
E0.4
A0.2
A0.2
RESET
RESET
AND
SET
AND
SET
Processor
S1
S2
S3
S4
K1
K2
K3
K4
H1
H2
K1 K2
K3 K4
+ +
S1
S2
S3
S4
E1
E2
E3
E4
H1
H2
A1
A2
+ +
TP 201, Transparency 42
Alterable Controls
S1
Switch
Inputs
Signalinput
Signaloutput
Signal processing
Relays Contacts
Outputs
S2
S3
S4
K1
K2
K3
K4
H1
H2
K1 K2
K3 K4
+ - + -
S1Program:
WHEN
THENOTHERWISE
WHEN
THENOTHERWISE
E0.1E0.2
A0.1A0.1
E0.3E0.4
A0.2A0.2
RESET
RESET
AND
SET
AND
SET
S2
S3
S4
E1
E2
E3
E4Processor
H1
H2
A1
A2
+ -+ -