basic pneumatic system
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1
Assembly & Maintenance of
Pneumatic & Hydraulic System
(SED 23103)
Basic Automation System
(SRD 23403)
Malaysian Spanish Institute
MSI Pneumatic System
v5
Assembly & Maintenance of Pneumatic & Hydraulic System
(SED 23103) - (Assessment)
1. Basic Pneumatic System – Technical Report 10%
– Mini Project 10%
– Test 10%
– Exam Practical 20%
2. Basic Hydraulic System – Technical Report 10%
– Mini Project 10%
– Test 10%
– Exam Practical 20%
• Total Marks (SED 23103) – Technical Report 20%
– Mini Project 20%
– Test 20%
– Exam Practical 40%
100%
2
MSI Electrical System
Assembly & Maintenance of Pneumatic & Hydraulic System
(SED 23103) - (Assessment)
1. Basic Pneumatic System – Pneumatic Power
– Pneumatic Control
– Pneumatic Actuator
2. Basic Hydraulic System – Hydraulic Power
– Hydraulic Control
– Hydraulic Actuator
• End of Course – Comparison of Power System
– Selection of Power System
3
MSI Electrical System
Assembly & Maintenance of Pneumatic & Hydraulic System
(SED 23103) (Study Planning)
1. Basic Pneumatic System – Week 1 – 6 (Study week)
– Week 7 (Practical Test)
2. Basic Hydraulic System – Week 8 – 13 (Study Week)
– Week 14 (Practical Test)
4
MSI Electrical System
Extra Assessment
Attitude marks
1. Attendant (per/minute = 0.019%)
2. Cheating (per/cheat = 1%)
3. Attire (per/day = 5%)
4. Behavior (per/hour = 5%)
Basic Automation System
(SRD 23403) - (Assessment)
1. Basic Electrical System – Technical Report 7%
– Mini Project 7%
– Test 7%
– Exam Practical 14%
2. Basic Pneumatic System – Technical Report 7%
– Mini Project 7%
– Test 7%
– Exam Practical 14%
3. Basic Hydraulic System – Technical Report 6%
– Mini Project 6%
– Test 6%
– Exam Practical 12%
• Total Marks (SRD 23403) – Technical Report 7+7+6%
– Mini Project 7+7+6%
– Test 7+7+6%
– Exam Practical 14+14+12%
100%
5
MSI Electrical System
Basic Automation System
(SRD 23403) - (Content Summary)
1. Basic Electrical System – Electrical Power
– Electrical Control
– Electrical Actuator
2. Basic Pneumatic System – Pneumatic Power
– Pneumatic Control
– Pneumatic Actuator
3. Basic Hydraulic System – Hydraulic Power
– Hydraulic Control
– Hydraulic Actuator
• End of Course – Comparison of Power System
– Selection of Power System
6
MSI Electrical System
Basic Automation System (SRD 23403)
(Study Planning)
1. Basic Pneumatic System – Week 1 – 4 (Study week)
– Week 5 (Practical Test)
2. Basic Hydraulic System – Week 6 – 9 (Study week)
– Week 10 (Practical Test)
3. Basic Electrical System – Week 11 – 13 (Study Week)
– Week 14 (Practical Test)
• Extra Assessment – Attitude marks
• Attendant (per/minute = 0.019%)
• Cheating (per/cheat = 1%)
• Attire (per/day = 5%)
• Behavior (per/hour = 5%)
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MSI Electrical System
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MSI Pneumatic System
Basic Pneumatic System
Malaysian Spanish Institute
9
Objective of Module
Why pneumatic system?
Because: relatively low cost, ease of installation, simple and robust
construction and ready availability in various sizes and stroke lengths. It is a basic control system. Uses air as its medium. Uses in low and medium
application.
Why learn pneumatic system? It is a basic control system.
Why learn maintenance of pneumatic system? To describe the methodology of preventive and corrective maintenance
technique of Pneumatic System.
MSI Pneumatic System
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Basic Control System
MSI Pneumatic System
signal
processing output
signal
input
pushbutton valve cylinder
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Control & Maintenance
MSI Pneumatic System
signal
processing output
signal
input
Assembly / Maintenance / Troubleshoot
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Content of Module
• CHAPTER 0 SAFETY IN PNEUMATIC SYSTEM
• CHAPTER 1 INTRODUCTION TO THE DIDACTIC UNIT
• CHAPTER 2 FUNDAMENTAL OF PNEUMATIC
• CHAPTER 3 PRODUCTION OF COMPRESSED AIR
• CHAPTER 4 DISTRIBUTION OF COMPRESSED AIR
• CHAPTER 5 MAINTENANCE UNIT
• CHAPTER 6 PNEUMATIC ACTUATOR
• CHAPTER 7 VALVES
• CHAPTER 8 MAINTENANCE IN PNEUMATIC SYSTEM
• CHAPTER 9 ELECTRO – PNEUMATIC SYSTEM
• CHAPTER 10 MAINTENANCE IN ELECTRO – PNEUMATIC SYSTEM
MSI Pneumatic System
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Safety in Pneumatic System chapter 0
MSI Pneumatic System
• To date, no standards exist with regard to the safety of pneumatic systems. Therefore
for all factors affecting safety, reference must be made to existing general
guidelines and regulations from a number of different engineering fields.
• Pneumatic systems using several force cylinders must be equipped with an
emergency switch. Based on the design and operating characteristics of a system,
the decision must be made as to whether the EMERGENCY-STOP function is:
– to put the system into the zero pressure status
– to reset all force cylinders into the initial position, or
– to inhibit all cylinders in their current position.
These three options can also be combined.
• Precautions must be taken to prevent ACCIDENT.
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MSI Pneumatic System
Safety Instructions
• Pneumatic workbench is must operated, installed or maintained properly by
students with supervised by lecturer
• Pneumatic workbench is used in an application for which it was designed.
• The advice of the legal requirements, the safety and the mounting instructions are
must be followed.
• Everybody responsible for the installation, operation or maintenance of this unit
must get familiarized with these instructions, especially those relating to safety.
• The installation and dismantled of all the components must only be done by
students with supervised by lecturer.
• When installing, dismantling or maintaining the unit ensure that the power
(pneumatic / electrical) supply is first disconnected.
• Modification of the unit in any form is forbidden without prior consultation with
lecturer.
• All safety regulations and all regulations for prevention of accidents in the operating
range are valid.
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Introduction to Pneumatic System chapter1
Pneumatic system uses “AIR” for their working medium.
The air from the atmosphere is reduced in volume by compression.
MSI Pneumatic System
Advantage of pneumatic system
• Availability
• Transport
• Storage
• Temperature
• Explosion proof
• Cleanliness
• Components
• Speed
• Overload safe
Disadvantage of pneumatic system
•Preparation
•Compression
•Force requirement
•Noise level
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Application Of Pneumatic System
General methods of material handling: (Clamping, Shifting, Positioning, Orienting, Branching of material flow)
General applications: Packaging, Filling, Metering, Locking, Driving of axes, Door or chute control,
Transfer of materials, Turning and inverting of parts, Sorting of parts,
Stacking of components, Stamping and embossing of components
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Pneumatic System Overview
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MSI Pneumatic System
Schematic Diagram Of A Pneumatic System
2(A)
1(P) 3(R)
2(A)
1(P) 3(R)
12(Z)
Single Acting
Cylinder
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MSI Pneumatic System
Schematic Diagram Of A Pneumatic System
2(B)4(A)
5(R)1(P)
3(S)2(A)
3(R)1(P)
Double Acting
Cylinder
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Working Principle (single acting cylinder)
MSI Pneumatic System
Retract position Extend position
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Working Principle (double acting cylinder)
Retract position Extend position
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Fundamental of Pneumatic Chapter 2
1. Physical Quantities
2. Basic Quantities
3. Derived Quantities
4. Characteristic of air
5. Newton’s Law
6. Pressure
7. Force
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MSI Pneumatic System
Physical Quantity
Air is a mixture of
• Nitrogen approx. 78 vol. %
• Oxygen approx. 21 vol. %
• It also contains traces of carbon dioxide,
argon, hydrogen, neon, helium, krypton
and xenon.
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MSI Pneumatic System
Basic Quantity
Basic Unit
Quantity Symbol Units
Length L Meter (m)
Mass m Kilogram (kg)
Time t Second (s)
Temperature T Kelvin (K, 0 °C = 273.15 K)
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MSI Pneumatic System
Derived Quantity
Derived units
Quantity Symbol Units
Force F Newton (N) = 1 kg • m/s²
Area A Square meter (m²)
Volume V Cubic meter (m³)
Flowrate qv (m³/s)
Pressure p Pascal (Pa)
1 Pa= 1 N/m² 5 1 bar = 10 Pa
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MSI Pneumatic System
Characteristic of Air
Air Pressure • Generally, in pneumatics all data concerning air quantity refers to the so-called
standard state. According to DIN 1343, the standard state is the status of a solid,
fluid or gaseous substance defined by standard temperature and pressure.
Standard temperature Tn = 273.15 K, tn = 0 °C
Standard pressure pn = 101325 Pa = 1.01325 bar
Figure: Air pressure diagram
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MSI Pneumatic System
Boyle-Mariottes’s Law
Air can be compressed and it’s tend to expand. The applicable relationship is
given in Boyle-Mariottes’s Law.
p1 • V1 = p2 • V2 = p3 • V3 = Constant
Air has no particular shape. Its shape changes with the shape of its surroundings.
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MSI Pneumatic System
Gay-Lussac’s Law
According to the Gay-Lussac’s law, the volume of a given mass of gas is
proportional to the absolute temperature as long as the pressure does not
change.
Where:
V1 = Volume at T1, V2 = Volume at T2
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MSI Pneumatic System
Newton’ Law
Newton’s Law: Force = mass • acceleration
F = m • a
where a is replaced by the acceleration due to gravity
g = 9.81 m/s²
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Force
• A force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of the objects. When the interaction ceases, the two objects no longer experience the force. Forces only exist as a result of an interaction.
MSI Pneumatic System
F = m • a
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MSI Pneumatic System
Pressure
Pressure: 1 Pascal is equal to the constant pressure on a surface area of 1 m² with the vertical force of 1 N (Newton).
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Pressure
• Pressure (symbol: p) is the force per unit area acting on a surface in a direction perpendicular to that surface. Mathematically:
• where:
MSI Pneumatic System
A
p
F
Area of double
acting cylinder
= π (d/2)²
Assignment 1 – AP1: Fundamental in Pneumatic
1. Find F1 if D1 is Ø32mm and p is 4bar.
2. Find the area if the pressure is 0.5MPa and the force acting at F1 is 200N
3. Find the pressure if force acting at F1 is 30kg and the bore diameter D1 of
the cylinder is Ø3.0cm
4. Find F1 and F2 if D2 is Ø22mm, D1 is 32mm and the p is 6 x 105 Pa.
(Force in N, Area in mm² and Pressure in bar)
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MSI Pneumatic System
p
F1 D1
F2
p
D2
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MSI Pneumatic System
Production of Compressed Air Chapter 3
For the continuous performance of control systems and working elements the air supply should:
• At the required pressure,
• Dry,
• Clean
If these conditions are not fulfilled, then problem of the system will occur. The effect
is downtime on the machinery in addition to increased costs for repair or replacement of parts.
The equipment to be considered in the generation and preparation of air:
- Inlet filter
- Air compressor
- Air reservoir
- Air dryer
- Air filter with water separator
- Pressure regulator
- Air lubricator as required
- Drainage points
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MSI Pneumatic System
Air Compressor
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MSI Pneumatic System
Air Compressor
• The selection from the various types of
compressors available is dependent upon
quantity of air, pressure, quality and
cleanliness and how dry the air should be.
• 3 main type of Air Compressor
1. Reciprocating Compressor
2. Centrifugal Compressor
3. Rotary compressor
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MSI Pneumatic System
Reciprocating Piston Compressor
The compressed air is drawn thru an inlet valve then the air is passed on thru an outlet valve via reciprocating piston .
Single stage
piston compressor
Double stage
piston compressor
Diaphragm
piston compressor
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MSI Pneumatic System
Working Principle (single stage piston)
At the end of the stroke, the
piston moves upward, the inlet
valve closes as the air is
compressed, forcing the outlet
valve open to discharge air into
air reservoir.
Air reservoir
Downward movement of the
piston increases volume to
create a lower pressure than
that of atmosphere, causing air
to enter the cylinder through
the inlet valve.
atmosphere
Working Principle (single stage piston)
• Piston travel downward
• Compression Chamber is at low pressure state (vacuum)
• Inlet valve open, atmospheric pressure will be sucked
into the compression chamber
• Piston travel upward
• Compression Chamber is at high pressure state
(compressed air)
• Outlet valve open, the compressed air will be pushed out
from the compression chamber.
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MSI Pneumatic System
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MSI Pneumatic System
Working Principle
atmosphere
compression
Compress
Air (3bar)
Inter-cooling
Compress
Air (7bar)
atmosphere
Compress
air
Double stage
piston compressor
Diaphragm
piston compressor
compression
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MSI Pneumatic System
Centrifugal & Rotary compressor
Sliding Vane
compressor
Screw
compressor
The rotary compressors use rotating elements to compress and increase the pressure of the air. During the compression process, the compression chamber is continually reduced.
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MSI Pneumatic System
Working Principle
Sliding Vane
compressor Screw
compressor
compression
Compress
Air
OUT
Atmosphere
IN
Assignment 2 - AP2: Pneumatic Compressor
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MSI Pneumatic System
• Working operation on: 1. Single Stage piston compressor,
2. Double Stage piston compressor,
3. Diaphragm piston compressor,
4. Single Chamber Vane compressor,
5. Double Chamber Vane compressor,
6. Screw compressor
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MSI Pneumatic System
Air Reservoir
• A reservoir is configured to:
• Stabilize compressed air.
• Compensates the pressure fluctuations.
• Air storage for continuous air supply. This has the advantage that the
compressor does not need to operate continuously.
• Cooling system for the compressed air.
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MSI Pneumatic System
Air Dryer
• Is used to eliminate Condensate (water) enters into
Pneumatic System through compressed air.
• Water causes problems related to corrosion and seal
wear.
• 3 type of dryer: • Low temperature drying
• Adsorption drying
• Absorption drying
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MSI Pneumatic System
Low Temperature Drying
The air entering into the refrigeration dryer is
pre-cooled in a heat exchanger by the
escaping cold air. It is then cooled in the
cooling unit to temperatures between + 2 and
+ 5 °C. The dried compressed air is filtered.
Before the compressed air is output into the
network, the air is heated to bring the air
back to ambient conditions.
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MSI Pneumatic System
Adsorption Drying
Adsorption: water is deposited on the surface
of solids.
The drying agent is a granular material (gel)
consisting almost entirely of silicon dioxide.
Usually two tanks are used. When the gel in
one tank is saturated, the air flow is switched
to the dry, second tank and the first tank is
regenerated by hot-air drying.
The lowest equivalent dew points (down to –
90 °C) can be achieved by means of
adsorption drying.
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MSI Pneumatic System
Absorption Drying
Absorption: A solid or liquid substance
bonds a gaseous substance.
Absorption drying is a purely chemical
process. Absorption drying is not of
major significance in present-day
practice, since the operating costs are
too high and the efficiency too low for
most applications.
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MSI Pneumatic System
Distribution of compressed air Chapter 4
• In order to ensure reliable and trouble-free air distribution, a number
of points must be observed. This includes primarily the correct sizing
of the pipe system, but also the pipe material, flow resistances, pipe
layout and maintenance.
• Pressure fluctuations in the network make it necessary to ensure
that the pipes are mounted securely in order to avoid leakages at
screwed and brazed connections.
• Two type of piping distribution layout:
– Dead End Line
– Ring
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MSI Pneumatic System
Piping Layout (Dead End Line piping Layout)
Pipe layout is the critical factor
in determining the economic
operation of the compressed-
air system. Compressed air is
fed into the system at intervals
by the compressor. It is often
the case that consumption at
consuming devices rises for
only a short time. This may
lead to unfavorable conditions
in the compressed-air network.
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MSI Pneumatic System
Piping Layout (Ring piping Layout)
• Therefore it is recommended that the compressed-air network should be produced in the form of a ring main. A ring main ensures largely constant pressure conditions.
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MSI Pneumatic System
Piping Layout (Ring piping Layout)
• For ease of maintenance, repair or extension of the network without
interfering with the overall air supply, it is advisable to sub-divide the
network into individual sections. Branches with T-pieces and
manifolds with plug-in couplings make this possible. It is advisable
to fit the branch lines with standard ball valves or shut off valves.
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MSI Pneumatic System
Piping Installation
• Despite the best water separation in the pressure generating system, pressure drops
and external cooling may produce condensate in the pipe system. In order to
discharge this condensate, the pipes should be inclined 1-2%; this can also be
carried out in stages. The condensate can then be discharged from the system via
water separators at the lowest point.
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MSI Pneumatic System
Maintenance Unit Chapter 5
• The individual functions of compressed air preparation, i.e. filtering,
regulating and lubricating, can be fulfilled by individual components.
These functions have often been combined into one unit, i.e. the
service unit.
• The air service unit is a combination of the following :
• Compressed air filter (with water separator)
• Compressed air regulator
• Compressed air lubricator
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MSI Pneumatic System
Maintenance Unit: Component Air filter:
The compressed air filter has the job of removing all contaminants from the compressed air
flowing through it as well as water which has already condensed.
Air regulator:
The purpose of the regulator is to keep the
operating pressure of the system (secondary
pressure) virtually constant regardless of
fluctuations in the line pressure (primary
pressure) and the air consumption.
Air lubricator:
The purpose of the lubricator is to deliver
a metered quantity of oil mist into a leg of
the air distribution system when
necessary for the operation of the
pneumatic system.
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MSI Pneumatic System
Maintenance Unit: Working
Operation
filter regulator lubricator
57
• There are two basic types of Pneumatic actuator:
– Rotary actuator
(motor / rotary)
– Linear actuator
(cylinder)
MSI Pneumatic System
Pneumatic Actuator Chapter 6
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MSI Pneumatic System
Type of Linear Actuator
Symbol
Single-acting
cylinder
Basic Construction Type
Double-acting
cylinder
Double-acting
cylinder with
end position
cushioning
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MSI Pneumatic System
Type of Linear Actuator
Symbol
Tandem
double-acting
cylinder
Basic Construction Type
Cylinders with
through
piston rod
Multiposition
cylinders
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MSI Pneumatic System
Rotary Actuator
Symbol
Rotary
cylinders
Basic Construction Type
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Valve Chapter 7
Directional Control Valve • Directional control valves are components which change, open or close flow paths in
pneumatic systems. They are used to control the direction of motion of power
components and the manner in which these stop. Directional control valves are
shown as defined in DIN ISO 1219.
Type • 2/2-way valve
• 3/2-way valve
• 4/2-way valve
• 5/2-way valve
• 5/3-way valve
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MSI Pneumatic System
Symbols for directional
control valves
• The following rules apply to the representation of directional control valves:
• Each different switching position is shown by a square.
• Flow directions are indicated by arrows.
• Blocked ports are shown by horizontal lines.
• Ports are shown in the appropriate flow direction with line arrows.
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MSI Pneumatic System
Type of Distribution Valve (symbol)
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Method of Actuation
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Method of Actuation
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MSI Pneumatic System
Port Designation
• A numbering system is used to designate directional control valves and is in
accordance with DIN ISO 5599-3. Prior to this a lettering system was utilized and
both systems of designation are presented here:
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Working Principle 3/2 Way Valve (Normally Close)
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MSI Pneumatic System
Working Principle 3/2 Way Valve (Normally Open)
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Working Principle 3/2 Way Valve (Normally Close)
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Basic Construction 4/2 Way Valve
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Basic Construction 5/2 Way Valve (Double Air Pilot)
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Basic Construction 5/3 Way Valve (Double Air Pilot)
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MSI Pneumatic System
Non Return Valve
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MSI Pneumatic System
Check Valve
Check valves can stop the flow completely in one direction. In the opposite
direction the flow is free with a minimal pressure drop due to the resistance
of the valve.
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MSI Pneumatic System
Shuttle Valve
X Y A
0 0 0
0 1 1
1 0 1
1 1 1
TRUTH TABLE
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MSI Pneumatic System
Dual Pressure Valve
X Y A
0 0 0
0 1 0
1 0 0
1 1 1
TRUTH TABLE
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Quick Exhaust Valve
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Flow Valve
Introduction Flow control valves are used to reduce the speed of a cylinder or a motor.
Type of control valve:
2. Throttle Valve
(two way flow control valve) - Restrict both direction of flow.
1. One Way Flow Control Valve - Restrict one direction of flow only.
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MSI Pneumatic System
Working Principle
One-way flow control valve
– The one-way flow control valve where the restrictor is only effective in one direction is a
combination of a restrictor and a non-return valve. The restrictor controls the flow rate in a
single direction dependent on flow. In the opposite direction, the full cross-sectional flow is
released and the return flow is at full pump delivery. This enables the one-way flow control
valve to operate.
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MSI Pneumatic System
Working Principle
Throttle Valve
– Flow control valves
influence the
volumetric flow of the
fluid in both directions.
Control flow in both direction
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MSI Pneumatic System
Combination Valve
1. Pressure sequence valve
2. Time Delay Valve
(Pneumatic Timer)
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MSI Pneumatic System
Pressure sequence valve
The principle on which this valve acts is the
same as for the pressure limiting valve. If the
pressure exceeds that set on the spring, the
valve opens.
The flow from 1 to 2 is closed. Outlet 2 is
opened only if a preset pressure has built up
in pilot line 12. A pilot spool opens the
passage 1 to 2.
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MSI Pneumatic System
Circuit Example
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MSI Pneumatic System
Time delay valve The time delay valve is a
combined 3/2-way valve, one
way flow control valve and air
reservoir. The 3/2-way valve can
be a valve with normal position
open or closed. The delay time is
generally 0-30 seconds for both
types of valves.
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Circuit Example
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MSI Pneumatic System
Pneumatic Counter
c a.z
b.y
1(P) 3(R)
2(A)
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MSI Pneumatic System
Circuit Example
Assignment 3
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MSI Pneumatic System
1. P1 AND P2 OR P3 Cyl. A ext
2. (P1 OR P2) AND (P3 OR P4) Cyl. A ext
3. (P1 AND P2) OR P3 OR P4 Cyl. A ext
4. (P1 AND P2 AND P3) OR P4 Cyl. A ext
Assignment 4
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MSI Pneumatic System
1. P1 AND P2 OR P3 Cyl. A ext
P4 Cyl. A ret
2. (P1 AND P2) Cyl. A ext
(P23 OR P4) Cyl. A ret
3. (P1 OR P2) AND P3 Cyl. A ext
(P4 AND P5) OR P6 Cyl. A ret
Assignment 5 & Assignment 6
slow slow fast
1. A+ B+ A- B-
fast slow slow
2. A+ B+ C+ A- B- C-
slow slow
3. A+ B+ A- C-
C+ B-
1. A+ A- B+ B-
2. A+ B+ B- A-
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91
Maintenance Chapter 8
• Systematic maintenance helps to extend service life and improve the
functional reliability of pneumatic control systems.
• A detailed maintenance plan should be drawn up for every pneumatic
system. A maintenance plan lists the maintenance tasks and time intervals.
In the case of complex control systems, the maintenance documentation
must include a function diagram and circuit diagram.
• The time intervals between individual maintenance work to be carried out is
dependent on the period of use, the wear characteristics of the individual
components and the ambient medium. The following maintenance work
must be carried out frequently and at short intervals:
– Service unit
• Check the filter
• Drain water regularly
• Refill and set lubricator, if a lubricator is used.
– Check signal generators for possible deposits of dirt or scarf
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Maintenance Procedure
MSI Pneumatic System
• The following maintenance work can be undertaken at
greater time intervals:
Check the seals of the connectors for leaks
Replace lines connected to moving parts
Check the rod bearings in the cylinders for wear and replace if
necessary
Clean or replace filter elements
Check function of safety valves
Check mountings
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MSI Pneumatic System
Control system development (design procedure)
The methods of representing the control problem include:
1. Positional sketch
2. Displacement-step diagram
3. Control chart
4. Function diagram
5. Function chart
6. Circuit diagram
Positional sketch
Displacement-step diagram
1
2
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Displacement-time diagram
Control chart
Function diagram
Function
chart
2
3
4
5
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MSI Pneumatic System
Circuit diagram 6
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Electro-Pneumatic System Chapter 9
Malaysian Spanish Institute
MSI Electro-Pneumatic System
Fathul Hazrimy Ahmad
Assistant Lecturer
Pneumatic Hydraulic Department
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MSI Electro-Pneumatic System
Schematic
Design Of An
Electro-
Pneumatic
System
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MSI Electro-Pneumatic System
Electro-Pneumatic System
Change
of Switching control
Y1
2(A)
1(P) 3(R)
P1
2(A)
1(P) 3(R)
Conventional Pneumatic Electro-Pneumatic
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MSI Pneumatic System
Conventional vs. Electro
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MSI Electro-Pneumatic System
Hydraulic Pump
Control
Valve
Cylinder
Power
Supply
Pushbutton
Relay,
Timer,
Solenoid
Electro-Pneumatic Overview
From electro
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MSI Electro-Pneumatic System
Electro-Pneumatic System
1. Safety precaution
2. Introduction
3. Advantages
4. Comparison
5. Electrical Fundamental
6. Electrical Input Element
7. Sensor
8. Relay
9. Solenoid
10. Electrical Timer
11. Sequence Control
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Safety Precaution
MSI Electro-Pneumatic System
1. Pneumatic safety must be apply
2. DO NOT wear sandals, wear covered shoes
3. DO NOT wear excessive jewelry
4. DO NOT wear swing-loose-long hair style, neatly tie-up the long hair or place under a proper head gear.
5. DO NOT wear shoes with heel higher than 1" (2.5 cm)
6. DO wear lab-coat all the time
7. DO NOT disturb people who are conducting experiments! (or any time)
8. NO eating or drinking inside the lab.
9. NO social gathering is allowed in the labs. The labs should not be crowded for non-working purposes.
10. In case of spilling water on a lab bench near power points, first SWITCH OFF the electrical power before cleaning.
11. TO INSPECT any electrical equipment, first turn the power off and ask for the instruction/help from the lab officer in charge. Any faulty equipment should be attended by trained personnel only. DO NOT do it on your own.
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Introduction
Electro-Pneumatic Systems are made up of
pneumatic and electrical components:
• The movements are generated by Pneumatic means
(e.g. by cylinders).
• Signal input and signal processing, on the other hand,
are effected by Electrical and Electronic
components (e.g. electromechanical switching
elements or stored-program controls).
MSI Electro-Pneumatic System
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Advantages
MSI Electro-Pneumatic System
• Electrical signals can be transmitted via cables quickly and easily and over great distances. Mechanical signal transmission (linkages, cable-pulls) or pneumatic signal transmission (tubes, pipes) are far more complex.
• In the field of automation, signal processing is generally effected by electrical means. This enhances the options for the use of electro-pneumatic systems in automatic production operations (e.g. in a fully automatic pressing line for the manufacture of car wings).
• Many machines require complex control procedures (e.g. plastics processing). In such cases, an electrical control is often less complex and more economical than a mechanical or pneumatic control system.
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MSI Electro-Pneumatic System Comparison
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MSI Electro-Pneumatic System
Electrical Fundamental
• The relationship between voltage, current strength and resistance is described by Ohm‘s law. Ohm‘s law states that in a circuit with constant resistance the current strength changes in proportion to the change in voltage:
– if the voltage increases, the current strength also increases.
– if the voltage falls, the current strength also decreases.
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MSI Electro-Pneumatic System
• In the field of mechanical engineering, power can be defined in terms of the work performed. The faster a task is performed, the greater the required power. Power therefore means work per unit of time.
• In the case of a consuming device in a circuit, electrical energy is converted into kinetic energy (e.g. electrical motor), light radiation (e.g. electrical lamp) or thermal energy (e.g. electrical heater, electrical lamp). The faster the energy is converted, the greater the electrical power.
Electrical power
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MSI Electro-Pneumatic System
• A power supply unit consists of the following modules:
– the mains transformer which transforms the alternating voltage of the mains supply (e.g. 220 V) into the output voltage (mostly 24 V).
– a smoothed direct voltage is generated by the rectifier G and the capacitor C.
– the direct voltage is then stabilized by the in-phase regulator.
Power Supply
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MSI Electro-Pneumatic System
• Electrical controls are generally supplied with a direct current of 24V.
The alternating voltage from the power supply therefore has to be
stepped down to 24V and then rectified.
Conversion AC to DC
AC DC
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MSI Electro-Pneumatic System
Electrical input elements
FUNCTION OF SWITCH: To open or close the flow of current to the consuming device.
TYPE: 1. "pushbutton switches" (push-buttons), and
2. "control switches".
CONTROL SWITCH:
In control switches, the two switching positions are mechanically interlocked. A switching position is maintained until the switch is activated once again.
PUSH-BUTTON: A push-button only opens or closes a current circuit for a short time. The selected switching
position is only active while the push-button is pressed.
Both switch types are available for operation with normally closed contacts, normally open contacts or
changeover contacts.
BASIC TYPE OF SWITCH:
1. Normally open contact
2. Normally closed contact
3. Changeover switch
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MSI Electro-Pneumatic System
Pushbutton (normally Open)
Circuit is open when the push-button is in the normal position
Pressed S1, H will on
Circuit Example:
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MSI Electro-Pneumatic System
Pushbutton (normally Close)
Circuit is closed when the push-button is in the normal position
Pressed S1, H will off
Circuit Example:
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MSI Electro-Pneumatic System
Changeover Switch
These contacts combine the functions of normally closed and normally
open contacts in one unit.
Pressed S1, H2 will on,
Release S1, H1 will on.
Circuit Example:
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MSI Electro-Pneumatic System
Switching Signal
And
Function
Or
Function
And
Function
Or
Function
Switching ON Command Switching OFF Command
S1 AND S2 H1 on S1 OR S2 H1 on S1 AND S2 H1 off S1 OR S2 H1 off
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MSI Electro-Pneumatic System
Assignment 7
1. Press S1 AND S2 H1 ON
2. Press S1 OR S2 H1 ON
3. Press S1 AND S2 AND S3 H1 ON
4. Press S1 OR S2 OR S3 H1 ON
5. Press (S1 AND S2) OR S3 H1 ON
6. Press (S1 OR S2) AND S3 H1 ON
7. Press (S1 OR S2) AND (S3 OR S4) H1 ON
8. Press (S1 AND S2) OR (S3 AND S4) H1 ON
9. Press (S1 AND S2 AND S3) OR S4 OR S5 H1 ON
10. Press [(S1 OR S2) AND S3] OR [(S4 OR S5) AND S6] H1 ON
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MSI Electro-Pneumatic System
24v
0v
S1
L1
S2
Installation Example #1 (Series)
11 12
23 24
31 32
43 44 H1
H2
H3
H1
H2
H3
11 12
23 24
31 32
43 44
11 12
23 24
31 32
43 44
11 12
23 24
31 32
43 44
0V
24V
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MSI Electro-Pneumatic System
Practical
1. Press S1 AND S2 H1 ON
2. Press S1 OR S2 H1 ON
3. Press S1 AND S2 AND S3 H1 ON
4. Press S1 OR S2 OR S3 H1 ON
5. Press (S1 AND S2) OR S3 H1 ON
6. Press (S1 OR S2) AND S3 H1 ON
7. Press (S1 OR S2) AND (S3 OR S4) H1 ON
8. Press (S1 AND S2) OR (S3 AND S4) H1 ON
9. Press (S1 AND S2 AND S3) OR S4 OR S5 H1 ON
10. Press [(S1 OR S2) AND S3] OR [(S4 OR S5) AND S6] H1 ON
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MSI Electro-Pneumatic System
Sensor
Any device that receives a signal (e.g. heat or
pressure or light or motion etc.) and responds
to it in a unique manner [synonym: detector]
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MSI Electro-Pneumatic System
Limit switch
A mechanical limit switch is an
electrical switch which is activated
when a machine part or a workpiece
is in a certain position.
Normally open limit switch
1-4
Normally closed limit switch
1-2
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MSI Electro-Pneumatic System
Pressure switch
requires a pressure to
activated the sensor
Normally open limit switch
1-4
Normally closed limit switch
1-2
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MSI Electro-Pneumatic System
Practical (Sensor)
Roller
Limit
Switch
1. 2. Pressure
Sensor a.
b.
a.
b.
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MSI Electro-Pneumatic System
Proximity Sensor
Proximity sensors is refer to Non-contacting sensors
Type of Proximity Sensor
1. Reed switch -
2. Inductive sensor –
3. Capacitive sensor -
4. Optical / Photo Sensor -
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MSI Electro-Pneumatic System
Reed Switch (magnetic sensor)
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MSI Electro-Pneumatic System
Inductive Proximity Sensor (sense materials with good electrical conductivity)
125
MSI Electro-Pneumatic System
Capacitive Proximity Sensor (sense all kind of material)
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MSI Electro-Pneumatic System
Optical/Photo Proximity sensor (sense reflected light)
Three type: • through-beam sensors
• retro-reflective sensors
• diffuse sensors
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MSI Electro-Pneumatic System
Optical Through-beam
Proximity sensor
128
MSI Electro-Pneumatic System
Optical Retro-reflective
Proximity sensor
129
MSI Electro-Pneumatic System
Optical Diffuse
Proximity sensor
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MSI Electro-Pneumatic System
Circuit Example
Proximity 2 wire
Proximity 3 wire PNP
Proximity 3 wire NPN
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MSI Electro-Pneumatic System
Practical (Sensor)
1. 2. 3. Reed
Switch
(Proximity
Magnetic
Sensor)
4.
Proximity
Inductive
Sensor
Proximity
Capacitive
Sensor
Proximity
Optical
Sensor
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MSI Electro-Pneumatic System
Relay
• Relays are electromagnetically actuated switches.
• They consist of a housing with electromagnet and movable contacts.
• An electromagnetic field is created when a voltage is applied to the coil of the electromagnet.
• This results in attraction of the movable armature to the coil core. The armature actuates the contact assembly.
• This contact assembly can open or close a specific number of contacts by mechanical means.
• If the flow of current through the coil is interrupted, a spring returns the armature to its original position.
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MSI Electro-Pneumatic System
Concept of a Relay
(Electromagnet)
• An electromagnet is a type of magnet in which the
magnetic field is produced by the flow of an electric
current. The magnetic field disappears when the current
ceases.
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MSI Electro-Pneumatic System
Working Principle
Relay
1 pole
Relay
2 pole
135
MSI Electro-Pneumatic System
Circuit Example
Direct Control In-direct Control
136
MSI Electro-Pneumatic System
Practical (Relay)
S1 H1 on
S1 H1 on, H2 off, H3 on, H4 off
S1 H1 on
S2 H2 off
1.
2.
3.
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MSI Electro-Pneumatic System
Assignment 8
1. Press S1 AND S2 H1 ON
Press S3 OR S4 H1 OFF
2. Press S1 AND S2 AND S3 H1 ON
Press S4 OR S5 OR S6 H1 OFF
3. Press (S1 AND S2) OR S3 H1 ON
Press (S4 OR S5) AND S6 H1 OFF
4. Press (S1 OR S2) AND (S3 OR S4) H1 ON
Press (S5 AND S6) OR (S7 AND S8) H1 OFF
5. Press (S1 AND S2 AND S3) OR S4 OR S5 H1 ON
Press [(S6 OR S7) AND S8] OR [(S9 OR S10) AND S11] H1 OFF
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MSI Electro-Pneumatic System
Practical
1. Press S1 AND S2 H1 ON
Press S3 OR S4 H1 OFF
2. Press S1 AND S2 AND S3 H1 ON
Press S4 OR S5 OR S6 H1 OFF
3. Press (S1 AND S2) OR S3 H1 ON
Press (S4 OR S5) AND S6 H1 OFF
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MSI Electro-Pneumatic System
Solenoids
• In electro-hydraulics, valves are actuated via solenoids. It has the
same concept of electromagnet.
solenoid
Directional control Valve
140
MSI Electro-Pneumatic System
Electrical Construction of Solenoid
141
MSI Electro-Pneumatic System
Electro-Pneumatic Circuit Diagram
Pneu
matic C
ircuit
Contro
l Circu
it
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MSI Electro-Pneumatic System
Assignment 9
1. Press S1 AND S2 Cly. A ext
2. Press S1 OR S2 Cly. A ext
3. Press S1 AND S2 AND S3 Cly. A ext
4. Press S1 OR S2 OR S3 Cly. A ext
5. Press (S1 AND S2) OR S3 Cly. A ext
6. Press (S1 OR S2) AND S3 Cly. A ext
7. Press (S1 OR S2) AND (S3 OR S4) Cly. A ext
8. Press (S1 AND S2) OR (S3 AND S4) Cly. A ext
9. Press (S1 AND S2 AND S3) OR S4 OR S5 Cly. A ext
10. Press [(S1 OR S2) AND S3] OR [(S4 OR S5) AND S6] Cly. A ext
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MSI Electro-Pneumatic System
Assignment 10
1. Press S1 AND S2 Cly. A ext
Press S3 OR S4 Cly. A ret
2. Press S1 AND S2 AND S3 Cly. A ext
Press S4 OR S5 OR S6 Cly. A ret
3. Press (S1 AND S2) OR S3 Cly. A ext
Press (S4 OR S5) AND S6 Cly. A ret
4. Press (S1 OR S2) AND (S3 OR S4) Cly. A ext
Press (S5 AND S6) OR (S7 AND S8) Cly. A ret
5. Press (S1 AND S2 AND S3) OR S4 OR S5 Cly. A ext
Press [(S6 OR S7) AND S8] OR [(S9 OR S10) AND S11] Cly. A ret
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MSI Electro-Pneumatic System
Practical
1. Press S1 AND S2 Cly. A ext
Press S3 OR S4 Cly. A ret
2. Press S1 AND S2 AND S3 Cly. A ext
Press S4 OR S5 OR S6 Cly. A ret
3. Press (S1 AND S2) OR S3 Cly. A ext
Press (S4 OR S5) AND S6 Cly. A ret
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MSI Electro-Pneumatic System
11.Sequence Control
• Single cycle (SC)
– In a single cycle mode, the sequence will run only in one cycle
via pushing a pushbutton.
– Example: A+ A-
• Continuous cycle (CC)
– In a continuous cycle mode, the sequence will run continuous
when start button is pressed, the sequence will stop until stop
button is pressed.
– Example: A+ A- A+ A- A+ A- …. Until stop is pressed
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MSI Electro-Pneumatic System
Assignment 11
1. A+ B+ A- B-
2. A+ B+ C+ A- B- C-
3. A+ A- B+ B-
4. A+ B+ A- C- A- B+
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MSI Pneumatic System
D’ END