czech technical university in prague faculty of mechanical
TRANSCRIPT
1
Czech Technical University in Prague
Faculty of Mechanical Engineering
Department of Automatic Control
Master Thesis
Title: Pressing Facility Pneumatic Control System Innovation
MESSAS CHAHIR 2016/2017
2
3
4
Prague – 2017
Master Thesis
I submit this thesis for review and defense in partial fulfillment of the requirements, for the
degree master at Czech Technical University in Prague.
I declare that this dissertation is my own work, and all the sources have been quoted and
acknowledged by means of complete references.
ACKNOWLEDGEMENTS
I would like to express my thanks to my supervisor Ing Marie Martinaskova, PhD,
who gives me the valuable instructions, advices and supports during my study.
Also for the lectures of Means of Automatic Control, this gave me knowledge during
my course.
I would like to give special thanks to my family and friends for encouragement, and patient
waiting me when I study abroad here.
Chahir Messas
Prague, January 2017
5
ABSTRACT
The pneumatic system is a domain of engineering which uses pressurized air or gas,
This master thesis analysis the pneumatic system according to a given facility sketch and
pneumatic control system drawing, and discuss the advantages and disadvantages, in
addition designs the possible changes to this system in nowadays for innovation purposes,
Also explains possible error states at the facility and their management.
6
Content
Chapter 1 Analysis of the pneumatic solution ......................................................................... 10
1.1-Introduction .................................................................................................................... 10
1.2-Methods that were used for solving this task ................................................................ 10
1.3-Description of the desired function of the facility ......................................................... 13
1.4-List of components ......................................................................................................... 14
1.5-List of components from laboratory ............................................................................... 18
Chapter 2-PLC solution ............................................................................................................. 21
2.1- General rules for electro-pneumatic circuit ................................................................. 21
2.2-Components of electro-pneumatic system .................................................................... 21
2.3-Advantages of electro-pneumatic systems .................................................................... 21
2.4-Block diagram ................................................................................................................. 25
2.5-Step Displacement Diagram (SDD) ................................................................................. 26
2.6-Time diagram .................................................................................................................. 27
2.7-Functionality of movement, steps .................................................................................. 28
2.8-State diagram .................................................................................................................. 29
2.9-State diagram process .................................................................................................... 29
2.10-PN (Petri Net) ................................................................................................................ 30
2.11-SFC Sequential Function Chart ..................................................................................... 31
2.12-GRAFCET implementation ............................................................................................ 32
2.13-Structure of GRAFCET ................................................................................................... 33
2.14-Real PLC implementation ............................................................................................. 35
2.14.1-PLC definition ............................................................................................................. 35
2.14.2-Programming language for PLC ................................................................................. 35
2.15-Method of solution ....................................................................................................... 42
2.16-Comparison of the electrical circuit with relays and their contacts and the program in
the ladder diagram ............................................................................................................... 43
2.17-Conclusion..................................................................................................................... 43
Chapter 3-Advantages and disadvantages of the pneumatic solution .................................... 44
3.1-Introduction .................................................................................................................... 44
3.2-Advantages ..................................................................................................................... 44
7
3.3-Disadvantages ................................................................................................................. 46
3.4-Conclusion ....................................................................................................................... 47
Chapter 4-Possible changes to the pneumatic solution ....................................................... 48
4.1-Possible changes ............................................................................................................. 48
4.2- Safety conditions for pneumatic system ....................................................................... 51
4.3 -Industy 4.0 ..................................................................................................................... 52
4.4 -Design principals ............................................................................................................ 52
4.5-Effect of industry 4.0 ...................................................................................................... 53
4.6-Conclusion ....................................................................................................................... 53
Chapter 5-Possible errors states in the facility and their management .................................. 54
5.1 Introduction .................................................................................................................... 54
5.2 Possible error states ........................................................................................................ 55
5.3- Conclusion ...................................................................................................................... 57
Chapter 6-Final Conclusion ...................................................................................................... 58
6.1-Conclusion ....................................................................................................................... 58
6.2- References ..................................................................................................................... 59
6.3-List of abbreviation ......................................................................................................... 60
6.4-Appendix ......................................................................................................................... 61
8
List of tables Table 1 Components used in the original circuit. .................................................................... 15
Table 2 PLC inputs. ................................................................................................................... 24
Table 3 PLC outputs .................................................................................................................. 24
Table 4 Functionality of all movement. .................................................................................... 28
Table 5 Description of state diagram ....................................................................................... 29
Table 6 Petri net places and transitions. .................................................................................. 31
Table 7 Advantages of the pneumatic system. ........................................................................ 45
Table 8 Disadvantages of the pneumatic system..................................................................... 46
Table 9 Pneumatic cylinder problem and recommended action. ............................................ 55
Table 10 Actuator moving slow problems and their management. ........................................ 55
Table 11 Flow control valve issues and their solutions. ........................................................... 56
Table 12 Low pressure problems and their management. ...................................................... 56
Table 13 Valve spool stuck issues and recommended actions. ............................................... 57
Table 14 Contamination in circuit problems and solutions. .................................................... 57
List of figures Figure 1 Press-in connection facility ........................................................................................ 13
Figure 2 Original pneumatic solution ....................................................................................... 14
Figure 3 First pneumatic solution ............................................................................................. 16
Figure 4 Second pneumatic solution ........................................................................................ 17
Figure 5 Linear double acting cylinder ..................................................................................... 18
Figure 6 Adjustable one way and flow control valve ............................................................... 18
Figure 7 3 /2-way valve NC (Normally Closed) with spring return ........................................... 18
Figure 8 5/2-way valve ............................................................................................................. 19
Figure 9 Quickstepper .............................................................................................................. 19
Figure 10 Shuttle valve ............................................................................................................. 19
Figure 11 Human Machine Interface (HMI) ............................................................................. 20
Figure 12 3/2-Way valve with push button, normally open .................................................... 20
9
Figure 13 Push button with arretation ..................................................................................... 20
Figure 14 3/2-way valve mechanically operated with spring return, contact end sensor roller
lever .......................................................................................................................................... 20
Figure 15 Electropneumatic solution ....................................................................................... 22
Figure 16 Virtual PLC circuit ..................................................................................................... 23
Figure 17 Block diagram ........................................................................................................... 25
Figure 18 Step Displacement Diagram (SDD) ........................................................................... 27
Figure 19 Time diagram ............................................................................................................ 27
Figure 20 State diagram ........................................................................................................... 29
Figure 21 Petri net .................................................................................................................... 30
Figure 22 Grafcet program ....................................................................................................... 32
Figure 23 Siemens PLC S7-200 ................................................................................................. 35
Figure 24 Step 7-micro/win 32 for PLC programming with Siemens S7-200 ........................... 35
Figure 25 Old and new double acting cylinder ......................................................................... 48
Figure 26 Flow control valve (linear vs. corner version) .......................................................... 48
Figure 27 New 5/2 way valve will be used instead of the old one .......................................... 49
Figure 28 PLC S7–200 replaces the quickstepper .................................................................... 49
Figure 29 3/2 way roller level valve and the new model ......................................................... 50
Figure 30 Industry 4.0 environment ........................................................................................ 52
Figure 31 Single acting cylinder. ............................................................................................... 61
Figure 32 Double acting cylinder. ............................................................................................. 61
Figure 33 5/2 Directional control valve. ................................................................................... 61
Figure 34 Shuttle valve. ............................................................................................................ 61
Figure 35 Cross section of a double acting cylinder. ................................................................ 62
Figure 36 PLC Siemens Simatic S7-300, 1200, 1500. ................................................................ 62
10
Chapter 1 Analysis of the pneumatic solution
1.1-Introduction
Pneumatic systems are power systems which use compressed air as a working medium for
the power transmission and for the control signals transmission.
An air compressor transforms the mechanical energy of the prime mover, to pressure energy
of the compressed air.
Such transformation simplifies the transmission, and storage, control of energy.
When compression is done, the compressed air must be well prepared for use.
Air preparation contains filtration, add lubricating oil mist.
The compressed air is stocked in compressed air reservoirs, and transmitted via transmission
lines: pipes.
The pneumatic power is controlled by means of a set of valves like the pressure, flow ect..
Then, the pressure energy is converted to the required mechanical energy through means of
the pneumatic motors and cylinders.
1.2-Methods that were used for solving this task
Chapter1
-Description of the task: Press-in connection facility, the original pneumatic solution with
quickstepper, and Human Machine Interface (HMI), (see figures 1 and 2).
-Tables: description list of components used for this solution divided into four parts:
actuating, processing, Human Machine Interface (HMI), sensors, (see table 1).
Also components used in the pneumatic solution, which are available at the university
laboratory, (see figures 5-14).
-Pneumatic circuits created in fluidsim: based on the original solution, a pneumatic circuit
with HMI (Human Machine Interface) and without HMI has been redrawn, (see figures 3 and
4) simulation the functionality of circuit has been studied and understood.
11
Chapter 2:
-Electropneumatic circuit: which is a preparation for the PLC solution, consist of main parts,
Electrical switches, electrical end sensors, relays, controllers, solenoid valves (see figure 15).
-Virtual PLC solution: has been done, the pneumatic part is the same, except:
-The valves must be solenoid ones.
-Instead of quickstepper, PLC has been used.
-All sensors must have electrical outputs (see figure 16).
-Block diagram: related to the structure of the whole system, which consists of the
technological process (TP) and control system (CS) and operator panel (OP), has particular
number of input and output necessary for the task control and their interconnection in this
system, (see figure 17).
-The algorithm for the functionality desired for the task: can be expressed in many ways:
step displacement diagram, time diagram, table of motor movements in particular steps,
causes and effects in particular steps, state diagram, Petri net, also the program in some
language (for better serve the graphical languages -(e.g. SFC, GRAFCET).
-Step Displacement Diagram (SDD): represents the operating of the actuators, which line
the displacement is recorded in relation to the sequence step, also signals causing each step
are involved with line (see figure 18).
-Time Diagram: is related to the step displacement diagram, on the horizontal axis, there is
time instead of the step (see figure 19).
Table: description of all the pneumatic solution steps, movements and their speed,
quickstepper inputs and outputs (see table 4).
-State diagram: illustrates the pneumatic solution, it is steps and transitions actions in each
step, it is shows in a graphical manner with help of nodes connected by directed graphs (see
figure 20).
-Petri net: is a collection of directed arcs connecting places and transitions.
Petri net models consist of two parts:
1. The net structure that represents the static part of the system.
2. A marking that represents the overall state on the structure (see figure 21).
12
-SFC and GRAFCET: Sequential Function Chart is a graphical programming language used
for (PLCs), similar to GRAFCET but not the same, the sequence of a GRAFCET is described by
the transitions from a previous to a subsequent step, steps and transitions have to alternate
in the plan (see figure 22).
-Real PLC implementation: After this general design the real implementation has be done,
the general algorithm expressed by many possible ways (tools) now it is necessary to
implement for the real PLC ( PLC S7-200 has been used, because it is in the lab at disposal
and i had some experiences with it from the exercises in the PCA class), and there are only
three languages at disposal in the Micro/win for programming it, LD, IL and FBD. So some
method must be used- moving chain method (suitable for the bistable valves at the
pneumatic motors) to assure the safe and reliable solution so important in the real industrial
automation. And this method is written in the language Ladder diagram - LD (it can be of
course written also in all other languages, that are there at disposal, the FBD or IL, but in the
LD there is the best readability), and the structure of the program is the same as the solution
in the classical electropneumatics (that’s the reason, why this solution has been prepared, to
understood the relationship and prepare the real implementation for the real PLC in the LD
diagram, (see figures 23,24).
13
1.3-Description of the desired function of the facility Press-in connection facility
On the pneumatic controlled press-in connection facility there are ND pieces to be
connected together step by step, there is possible to change the number of the pieces in one
batch at any time from some HMI facility (textual operator panel or PC with visualization
application) and it will be valid from the next piece in the batch.
One working cycle follows these conditions: after indicating of the right clamping of the
piece (block) via a sensor the processing of one couple begins. The sectional die on the
pneumatic motor a presses the cylinder in-the two pieces in the couple together-via one
slow and then one quick stroke.
Then the motor A must stay in the extracted position and damp the piece until the
pneumatic motor B will have pressed the securing bolt from the side. Pressing in of the
securing bolt is done by one slow and two quick strokes. Then the pneumatic motor C throws
away the completed couple and the next couple of the piece can be brought in.
Figure 1 Press-in connection facility
14
The circuit below represents the original pneumatic solution, with quickstepper and Human Machine Interface (HMI), as given in the task description.
Figure 2 Original pneumatic solution
15
1.4-List of components [1] Pneumatic symbols are utilized to illustrate the function of the different valves, and other devices which are connected together to compose circuits, sub circuits.
The table below illustrates all the components used in the original solution.
Component name Symbol Number of use
-Linear double acting cylinder.
3
-Adjustable one way and flow control valve.
3
-3/2-way valve, NC (Normally Closed) with spring return.
3
-3/2-way valve, NO (Normally Opened) with spring return.
2
4/2-way valve.
3
-Shuttle valve (OR function).
8
-3/2 way valve with lever switch.
2
-Quickstepper.
1
3/2-way valve with push button normally closed.
2
3/2-way roller level valve.
6
Table 1 Components used in the original circuit.
2
13
2
13
4 2
1 3
1 1
2
2
1 3
A1 A2 A3 A4 A5 A6 A7 A8 A9 A10A11A12
X1 X2 X3 X4 X5 X6 X7 X8 X9 X10 X11 X12
P
MAN/P
AUTO
L
2
1 3
21 3
16
This pneumatic solution circuit has been created in fluidsim, after studied and understood
the original circuit.
Figure 3 First pneumatic solution
42
13
11
2
2 13
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10A
11A12
X1X2
X3X4
X5X6
X7X8
X9X10
X11X12
PMA
N/P
AU
TO
L
11
2
42
13
11
2
2 13
11
2
11
2
11
2
B0
B1
B2
B3
42
13
B4
B5
213
B5
213
B3
213
B0
213
B1
213
213
213
B4
213
213
213
213
11
2
213
213
AB
C
EN
DS
TAR
TN
ON
-STO
PA
UTO
/MA
XFO
R-M
AN
/P21
3
B2
0.1
1.0
2.0
3.0
0.2
1.1
2.1
3.1
1.012.01
3.011.03
2.03
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
1.101.11
1.12
1.13
1.14
1.15
1.16
1.171.18
1.191.20
1.211.22
23
45
67
89
1011
20 40 60 80
100
1.0P
osition
mm
20 40 60 80
100
2.0P
osition
mm
20 40 60 80
100
3.0P
osition
mm
Designation
Quantity
value
17
This second pneumatic solution circuit was created in fluidsim as well after studying the
original solution, without using the HMI (Human Machine Interface).
Figure 4 Second pneumatic solution
AB
C
A1A2
A3A4
A5A6
A7A8
A9A10A11A12
X1X2
X3X4
X5X6
X7X8
X9X10X11X12
PMAN/P
AUTO
L
213
B52
13
B2
213
B321
3
B021
3
B121
3
213
213
11
2
213
B421
3
42
13
11
2
2 13
11
2
42
13
11
2
2 13
11
2
11
2
11
2
B0B1
B2B3
42
13
B4B5
NON-STO
PSTART
AUTO/M
AX
0.1
FOR M
AN/P
0.2
1.21.3
1.41.5
1.61.7
1.81.9
1.111.10
1.02.0
3.0
1.012.01
3.01
1.12.1
3.1
1.12
1.131.14
1.151.16
1.171.18
1.032.03
2526
2728
2930
3132
3334
20 40 60 80
100
1.0Position
mm
20 40 60 80
100
2.0Position
mm
20 40 60 80
100
3.0Position
mm
DesignationQuantity value
18
1.5-List of components from laboratory
A- Actuating part
Figure 5 Linear double acting cylinder [3]
A double-acting cylinder is a cylinder in which the working fluid works alternately on both sides of the piston, it has a port at each end,
This is used where an external force is not available to retract the piston or where high force is required in both directions of travel.
Figure 6 Adjustable one way and flow control
valve [3]
The one-way flow control valve contains a combination of a flow control valve and a non-return valve, which blocks the flow of air in one direction, whereby the air flows through the flow control valve. The throttle cross section can be adjusted by means of a knurled screw.
The settings are fixed by means of a knurled nut. Two arrows indicate the direction of flow control on the housing. In the opposite direction, the air flow is unrestricted through the non-return valve.
Figure 7 3 /2-way valve NC (Normally Closed)
with spring return [3]
The 3/2 way valve is designated NC
(Normally closed) when it reads
logic 1 in the normal state (no
subject detected).
The switching output transmits logic
0 to the controller. Seen from a
switching technology standpoint,
this sensor thus corresponds to
normally closed contacts.
19
Figure 8 5/2-way valve [3]
5/2-way valve, from the name itself
has 5 ports equally spaced and 2
flow positions.
B- Processing
Figure 9 Quickstepper [3]
Quickstepper Ports:
P -Source of the pressure air.
Auto-mode selection.
Man/P-mode selection.
Man-manual without P/ P- with P
- Automatically
(X1 – X12 ) -inputs- switching to the next step (phase).
L - Reset (setting of the A12 to 1).
(A1 – A12 ) -outputs- creating of the
steps (phases)- signals for the valves of the pneumatic motors.
Figure 10 Shuttle valve
[3]
A shuttle valve permits fluid to flow through it from one of two sources, so it works as an OR gate, It has two inlets (P1, P2) and one air outlet (A).
20
C- Human Machine Interface
Figure 11 Human Machine Interface (HMI) [3]
Human Machine Interface consists of: Three (3/2 way valves), Two normally open and one normally closed, and two Shuttle valves (OR blocks).
Figure 12 3/2-way valve with push button,
normally open
[3]
The 3/2-way valve with plug-in connections is assembled in a plastic housing. The unit is mounted on the profile plate via a quick release detent system with blue lever (mounting alternative "A").
When the push button is pressed the valve is actuated, and when it is released the valve will returns to the normal position through a return valve.
Figure 13 Push button with arretation[3]
Pneumatic pushbutton with arretation valves are available with an assortment of mechanical button actuators, Pushbuttons are basically used for starting and stopping operation of machinery, they also provide manual override at emergencies.
D- Sensors
Figure 14 3/2-way valve mechanically operated
with spring return, contact end sensor roller
lever [3]
The roller lever valve is actuated when the roller lever is pressed, for instance by the cam of a cylinder. After release of the roller lever, the valve is returned to its normal position using a return spring.
21
Chapter 2-PLC solution
2.1- General rules for electro-pneumatic circuit [2]
-The electro-pneumatic circuit diagram is divided into pneumatic and electrical sections,
Which are drawn separate, but they are strongly related via the labels, sensors and coils.
-For the pneumatic part, the signal flow is shown from the bottom to the top and it is the
reverse for the electrical part.
-In the electrical circuit diagram, the current paths are numbered respectively from left to
right.
-The common circuits diagram elements compose the interfaces between the electrical
and pneumatic circuits.
-Speed control: related only to the pneumatic part of the circuit, for decreasing of the
speed one-way flow control valves can be used, in the inlet - primary speed control–In the
outlet – secondary speed control, For increasing of the speed quick exhaust valve can be
used.
2.2-Components of electro-pneumatic system [4] The electro pneumatic system consists of the following items:
-DC power supply: to reduce and convert the 230 V AC to a 24 V DC.
- Switches: are installed in an electric circuit, to connect or interrupt the electric current.
- Relays: are defined as electromagnetically actuated switches.
- Solenoid valves.
- Sensors.
2.3-Advantages of electro-pneumatic systems [4] -Reduced installation complexity: less components and tubing, leads to less effort in planning and costs mostly with complex and large systems.
-Easier modification of the control system, it is easier to modify programs and change wiring, instead of changing mechanical devices and pipes networks.
-Better reliability less moving parts risk, comparing with mechanical control systems.
-More Secure: fewer tubing.
-Easier to handle: less complexity.
-Environmentally-friendly coupling system it require less lubrication.
22
The electro pneumatic circuit has been done, using moving chain method, the signal is not reset in every time but resets at the end of the signals, the circuit is represented below
Figure 15 Electropneumatic Solution
PMA
PMB
PMC
B0B1
B2B3
B4B5
42
51
3
YBF
YBB
42
51
3
YC
FY
CB
42
51
3
YAF
YAB
0.1
2 13
YAF1
+24V
0V
K4
A1A2
K6
A1A2
YAF
YAB
YBF
YBB
K1
34
K2
34
K6
34
K8
34
S1
34
B0
34
B2
34
B4
34
K7
A1A2
K1 34
K1
A1A2
K2
12
B134 K2
34
K2
A1A2
K3
12
K5
12
B0
34 K4
34
YAF1
K5
34
K4
12
K4
34
K3
A1A2
K2
34
K3
34
B0
34 K3
34
K1
34
K6
34
K7
12
K8
12
K7
34
2 13
YBF1
K5
A1A2
K6
12
B2
34 K5
34
K4
34
K5
34
K6
34
B1
34
B3
34
K8
A1A2
K9
12
K7
34 K8
34
B3
34
K9
A1A2
K10
12 K9
34
B2
34
K8
34
K9
34
K10
A1A2
K11
12
K9
34 K10
34
B3
34
K11
A1A2
K12
12 K11
34
B2
34
K10
34
K10
34
K11
34
K12
A1A2
K13
12
K11
34 K12
34
B3
34
K13
A1A2
K14
12 K13
34
B2
34
K12
34
K12
34
K14
A1A2
K15
12
K13
34
B2
34 K14
34
K15
A1A2
K16
12
K14
34
B0
34 K15
34
YC
FY
CB
K15
34
K16
A1A2
K15
34 K16
34
B534
K16
34
K14
34
YBF1 K9
34 K11
34
K1
12
AB
C1
.02
.03
.0
1.0
11
.03
1.1
2.0
12
.03
2.1
3.0
13.1
K1634
02
46
810
1214
1618
20
20 40 60 80
100
PMA
Position
mm
20 40 60 80
100
PMB
Position
mm
20 40 60 80
100
PMC
Position
mm
Designation
Quantity value
12
34
56
78
910
1112
1314
1516
1718
1920
2122
2324
2526
2728
2930
3132
3334
3536
3738
3940
4142
4344
4546
4748
49
3435
325637
178
491036
6111239
8131440
101516
12171845
1419204143
16212246
1823244244
20252647
222728
24293038
26313248
2823349
30
23
For PLC solution, the pneumatic part is the same, except:
-The valves must be solenoid ones.
-Instead of quickstepper, PLC will be used,
-All sensors must have electrical outputs.
The circuit below illustrates the PLC solution
Figure 16 Virtual PLC circuit
YBF
YAB
YBB
YAF
0V
+24V
YC
FY
CB
B534
B334
B134
B034
B2
34
B434
YAF1
YBF1
S34
B0B1
B2B3
B4B5
42
51
3
YBF
YBB
42
51
3
YC
FY
CB
42
51
3
YAF
YAB
0.1
2 13
YAF1
2 13
YBF1
1.02.0
3.0Text
Text
Text
1.012.01
3.01
1.1
2.1
3.1
1.032.03
BB0Y
YAF
BB1Y
YAB
BB2Y
YBF
BB3Y
YBB
BB4Y
YC
F
BB5Y
YC
B
SS1Y
YAF1
EECY
YBF1
GR
AFCET
INO
UT
EC34
AB
C
01
23
45
67
89
10
20 40 60 80
100
1.0Position
mm
20 40 60 80
100
2.0Position
mm
20 40 60 80
100
3.0Position
mm
Designation
Quantity value
12
34
56
78
16
24
-(S) Start button (SS1=1)
-(EC) Reset
-BB0 Sensor of pneumatic motor A is in backward position (BB0=1)
-BB1 Sensor of pneumatic motor A is in forward position (BB1=1)
-BB2 Sensor of pneumatic motor B is in backward position (BB2=1)
-BB3 Sensor of pneumatic motor B is in forward position (BB3=1)
-BB4 Sensor of pneumatic motor C is in backward position (BB4=1)
-BB5 Sensor of pneumatic motor C is in forward position (BB5=1)
Table 2 PLC inputs.
-YYAF Coil for pneumatic motor A forward
-YYAB Coil for pneumatic motor A backward (YYAB=1)
-YYBF Coil for pneumatic motor B forward (YYBF=1)
-YYBB Coil for pneumatic motor B backward (YYBB=1)
-YYCF Coil for pneumatic motor C forward (YYCF=1)
-YYCB Coil for pneumatic motor C backward (YYCB=1)
-YYAF1 Speed control, solenoid, A motor (1 = fast, 0 = slow)
-YYBF1 Speed control, solenoid, B motor (1 = fast, 0 = slow)
Table 3 PLC outputs.
25
2.4-Block diagram [2]
The block diagram, illustrates the inputs and outputs of the control system in general.
Figure 17 Block diagram
OP: Operator Panel.
TP: Technological process.
Control system: can be PLC, Quickstepper…
As shown in the block diagram above, there is a start button (SS) to start the whole
process In the Operating Panel.
The control system, PLC for example will use this start button signal as an input, as
well as the signals of the position sensors of the PMs (BB0, BB1, BB2, BB3, BB4, and
BB5).
PLC controls the coils through its output signals (YYAB, YYAF, YYBB, YYBF, YYCB, and
YYCF) which make the PMs A, B and C moving either backward or forward.
26
-PLC inputs
S – Start button (SS1=1)
BB0 – Sensor of Pneumatic Motor A is in backward position (BB0=1)
BB1 – Sensor of Pneumatic Motor A is in forward position (BB1=1)
BB2 – Sensor of Pneumatic Motor B is in backward position (BB2=1)
BB3 – Sensor of Pneumatic Motor B is in forward position (BB3=1)
BB4 – Sensor of Pneumatic Motor C is in backward position (BB4=1)
BB5 – Sensor of Pneumatic Motor C is in forward position (BB5=1)
-PLC outputs
YYAF – Coil for Pneumatic Motor A forward (YYAF=1)
YYAB – Coil for Pneumatic Motor A backward (YYAB=1)
YYBF – Coil for Pneumatic Motor B forward (YYBF=1)
YYBB – Coil for Pneumatic Motor B backward (YYBB=1)
YYCF – Coil for Pneumatic Motor C forward (YYCF=1)
YYCB – Coil for Pneumatic Motor C backward (YYCB=1)
YAF1 – Speed control, solenoid, A motor (1 = fast, 0 = slow)
YBF1 – Speed control, solenoid, B motor (1 = fast, 0 = slow)
2.5-Step Displacement Diagram (SDD) [2]
Represents the operating sequence of the actuators, which line the
displacement is recorded in relation to the sequence step, also signals
causing each step are involved with line.
It is useful for illustration of the movements for the particular pneumatic
motors in the particular steps.
-The movement of every pneumatic motor (position) is represented in the
coordinates Step (horizontally) and Position (vertically).
-End positions of the motors are marked (0 and 1), position is assumed to
be a linear function of the step.
-The real speed of the movement is not mentioned in this type of diagram,
the steps are equidistant.
27
Figure 18 Step Displacement Diagram (SDD)
2.6-Time diagram [2]
Time diagram is connected to the Step displacement diagram, on the
horizontal axis, there is time instead of the step.
- In this diagram, it is possible to represent different speeds of the
pneumatic motors movement.
- Usually time diagram is used for the tasks where the speed of the
pneumatic motor is controlled.
-Decreasing of the speed with the help of the one-way flow control valve
-Increasing of the speed with the help of the quick exhaust valve.
Figure 19 Time diagram
COMPONENT DESIGNATION SIGNAL
1 2 3 4 5 6 7 8 910
112 = 1
TIME DIAGRAM
PM A
1
0
PM B
1
0
PM C
1
0
28
2.7-Functionality of movement, steps
The table below describes this pneumatic solution twelve steps with their causes, the quickstepper inputs and outputs, and the movements and their speed either it is slow, quick or nominal.
Speed: S: slow, Q: quick, N: nominal, Movements: (+ Forward), (- Backward).
Steps Causes Quickstepper inputs
Mouvements Speed Quickstepper
Outputs
1 A1 X1 A+ S A1
2 A0 X2 A- N A2
3 A1 X3 A+ Q A3
4 B1 X4 B+ S A4
5 B0 X5 B- Q A5
6 B1 X6 B+ Q A6
7 B0 X7 B- N A7
8 B1 X8 B+ N A8
9 B0 X9 B- N A9
10 A0 X10 A- Q A10
11 C1 X11 C+ S A11
12 C0 X12 C- N A12
Table 4 Functionality of all movement.
29
2.8-State diagram [2]
This diagram illustrates the pneumatic solution, it is steps and transitions actions in
each step, it is shown in a graphical manner with help of nodes connected by directed
graphs.
Figure 20 State diagram
State Description 7 B forward 1
1 INITIAL 8 B backward 1
2 A forward 9 B forward 2
3 B backward 10 B backward 2
4 A forward hold 11 A backward done
5 B forward 12 Throw
6 B backward 13 Throw done.
Table 5 Description of state diagram.
2.9-State diagram process State diagram process is starting in initial state (1) where all PMs A, B and C are moved
backward, next state “A forward” will be triggered by start button signal SS1, and the PM
backward sensor signals (BB0, BB2, BB4).
In this state the cylinder will be pressed in by moving the PMA forward slowly
(YYBF1=0). When this is done, PM forward sensor signal A (BB1), the PM will be
moved backward fast,
30
In the next state “A backward”. To hold the work piece during further manufacturing
PM A is moved forward again in the next state “A forward hold”.
The movement is fast since the solenoid variable is still set on fast movement
(YYAF=1). When the sensor for forward position of PMA is triggered, next state “B
forward” starts, where PMB is slowly (YYBF1=O) moved forward to press in the
securing bolt.
When this is done PMB is moved backward in state “B backward”, The work piece
must be pressed two times short (YYBF=1) then to finish the securing bolt,
In the next states “B forward 1”, “B backward 1”, “B forward 2”, “B backward 2” using
PMB. After this manufacturing, which ends with “B backward 2” done”,
PMA which is still 6TH STATE, holding the work piece is moved backward to set it free
in state “A Backward done”.
The work piece is thrown out then by PMC using a slow forward and a normal speed
backward move, done in states “Throw” and “Throw done”.
When the sensor for C backward position (EEC) is triggered, the cycle ends by
processing to initial state.
2.10-PN (Petri Net) [2]
A Petri Net is a collection of directed arcs connecting places and transitions.
Petri net models consist of two parts:
1. The net structure that represents the static part of the system.
2. A marking that represents the overall state on the structure.
Figure 21 Petri net
31
Table 6 Petri net places and transitions.
2.11-SFC Sequential Function Chart [16]
(SFC) is a graphical programming language used for (PLCs), it is one of the five languages
defined by IEC 61131-3 standard. The SFC standard is defined as, preparation of function
charts for control systems, and was based on GRAFCET (itself based on binary petri nets).
It can be used to program processes that can be split into steps.
Main components of SFC are:
-Steps with associated actions.
-Transitions with associated logic conditions.
-Directed links between steps and transitions.
32
2.12-GRAFCET implementation This figure illustrates the GRAFCET used for this PLC solution.
Figure 22 GRAFCET program
1 YYAB
YYAF2
YYBB YYCB
SS1 * BB0 * BB2 * BB4
YYAB3
YYAF4
YYBF5
BB1
YYBB6
BB3
YYBF7
BB2
BB3
YYAB11
YYCF12
BB0
YYCB13
BB5
14 YYBF1 := 0
YYBF1 := 1
YYBB8
YYBF9
BB2
YYBB10
BB3
BB4
BB0
BB1
BB2
YYAF1 := 0
ECC
YYAF1 := 1
33
2.13-Structure of GRAFCET [7]
GRAFCET is a graphic description language which describes the logical behaviour
and
operation of a control system or a process.
FluidSIM can be used to both create and simulate GRAFCET plans.
A GRAFCET basically illustrates two aspects of a control system, according to
particular
rules: the actions (commands) to be carried out and the sequence of execution. The
elementary components of a GRAFCET are actions, steps and transitions and can be
used
in the same way either as electrical or pneumatic components. To realize a uniform
operating concept, the GRAFCET elements feature connections that can be used to
link
them to each other (as with all other FluidSIM components).
-Steps
There are two types active or inactive and can be linked by actions. The actions of
active steps are executed. The sequence of a GRAFCET is illustrated by the transitions
from a previous to a next step. Both steps and transitions have to alternate in the
plan.
Every step has to be assigned a name, if a step is to be active at the start of the
sequence control, it is marked initial step.
Active steps are marked with a point, also active steps are framed in green.
-Actions
To perform commands, it is required to link any number of actions to a step, actions
do not have to be directly linked to a step, it is possible to link them to each other.
the purpose is to make it easier to create the drawing, it is sufficient to place actions
next to each other, without having to draw connecting lines. If the connections for
the elements overlap each other, it means they will be automatically connected.
1
1
34
Actions it is defined by a textual description or by setting or changing variable values.
To simulate a GRAFCET with FluidSIM, the variable values are taken into account in
the simulation.
When displaying a GRAFCET graphically, there is a chose whether the variable name
or the descriptive text is shown in an action. To display the description, set the
checkmark next to "Display description instead of formula" in the action's properties.
There are two types of action:
-Continuously effective and stored effective actions. For a continuously effective
action, its linked variable is set to the Boolean value "TRUE" (1), provided that the
step connected to the action is active. If the step is inactive, the value is set to
"FALSE" (0). This way of setting a variable is referred to as "assignation" in the
GRAFCET specifications.
-For a stored effective action, the set value of the variable remains unchanged until it
is changed by another action. This way of setting a variable is referred to as
"allocation" in the GRAFCET specifications.
At the start of a sequence, all the variable values are in initialise with "0".
-Transitions
Are used to describe the sequence of a control system.
35
2.14-Real PLC implementation
2.14.1-PLC definition [5], [6]
Programmable Logic Controller (PLC) is a digital computer used for automation of
industrial processes, such as control of machinery on factory assembly lines.
It is designed for multiple inputs and output arrangements, extended temperature
ranges, immunity to electrical noise, and resistance to vibration and impact.
A PLC is an instance of a hard-real-time system, because output results must be
corresponding to input conditions, or other operation will result.
Figure 23 Siemens PLC S7-200 [3]
2.14.2-Programming language for PLC [6]
The PLC product line from Siemens is named S7 (Step 7 PLC), the smallest PLC model
is the Siemens S7-200 PLC, there is also Siemens S7-300, Siemens s7-400, Siemens S7-
1200 and the newest PLC system in the line is the Siemens S7-1500.
Figure 24 Step 7-micro/win 32 for PLC programming with Siemens S7-200 [6]
The software used to program the S7 PLC’s is STEP 7-Micro/WIN, programming the
Siemens S7-200 PLC with one of the standard PLC programming languages as described
36
in the IEC 61131 standards, the languages you can use with STEP 7-Micro/WIN are:
-Ladder Logic (LAD), -Function Block Diagram (FBD).
-Instruction List (IL) in Siemens PLC’s, called Statement List (STL).
With that PLC programming languages, there is a lot of instructions available, from
simple binary instructions and word operations to program control with master
control relays (MCR) and even PID-loops, for better understanding, this is an example
of Programming of S7-200 by using Step 7–Micro/WIN. Inputs will be defined as IX.X,
outputs will be defined as QX.X and flags will be defined as MX.X for programming
Siemens PLCs. For instance, I0.1 defines the first module’s first input and Q0.1 defines
first module’s first output.
Using step7-micro / win to produce the program for the used PLC. Step7-Micro /
WIN is a software package which includes all tools for programming S7-200 family
controllers. User can choose between two of the more useful graphical programming
styles, LAD and instruction language, a real PLC program is shown below
37
38
39
40
41
42
43
2.15-Method of solution Detecting chain algorithm in coding has been used. It is the most used algorithm in industries
because it shows where the error in the coding.
-The program in the step7 micro/win will execute recursively in a chain so it is effective to use
the detecting chain algorithm. The code executes from one network to another sequentially
and at ends it will form a loop and again the control will come to first network.
2.16-Comparison of the electrical circuit with relays and their contacts and the program in the ladder diagram [2]
-By turning the diagram of the electrical circuit with relays and their contacts with the firm
point "0 + 24 V" from its horizontal position down to the vertical position we can get directly
the related programm in the Ladder diagram language.
-This is the original cause, why and how this ladder diagram language was created.
-Actually for the workers and operators of the machines, to understand in the program
what they have been used to understand in
the firm wiring of the relays and contacts in the control cabinet.
-In the PLC "the same structure of the wiring" is expressed in the program in the ladder diagram language.
2.17-Conclusion -This chapter illustrates the electropneumatic circuit which is a preparation for the PLC
virtual solution also graphical language grafcet was presented, then a real PLC SIEMENS
SIMATIC S7-200 program using step 7 micro/win software.
44
Chapter 3-Advantages and disadvantages of the pneumatic solution
3.1-Introduction Pneumatic systems are designs that use pressurized gas to power machines and tools, this
chapter discuss the pneumatic systems advantages and disadvantages.
3.2-Advantages [9], [10]
The table below describes the advantages of the pneumatic system, according to this task.
Advantages Descriptions
-Simple design
The designs of pneumatic system components are simple.
So they are more suitable for use in simple automatic
control systems.
Movement can be either linear or angular rotational
movement with simple and continuously variable
operational speeds.
-Environmental friendly
The pneumatic systems operation does not produce
pollutants. Those systems are environmentally clean and
with proper exhaust air treatment can be installed to clean
room standards.
-Unlimited availability of
the source
Practically air is available everywhere in the infinite
quantities.
-Temperature is flexible Air utilized at different temperatures are requested even in
extreme conditions, the air was able to work.
-Safe The air is not flammable also does not short circuit occurs,
so no danger of fire or explosion.
-Transport Air can be easily transported from one place to another
through pipelines.
-Easy to store The air is stored through the seat tube supply surplus air
pressure.
-Cleanliness The air is tending to clean without chemicals, also it can be
cleaned with some simple processes.
-Economical
The costs of pneumatic systems are quite low, moreover as
pneumatic systems are very durable, the maintenance is
lower than that of other systems.
45
-Easy to use Air is used to clean surfaces through pneumatic equipment,
to produce some movements.
-Maintenance The system components should be lubricated with oil on a
particular basis to avoid damages
-Pneumatic actuators
have long life
It performs well with only basic maintenance required.
-Easy selection of speed
and pressure
The speeds of rectilinear and oscillating movement of
pneumatic systems are quite easy to regulate and subject to
few limitations. The pressure and the volume of air can be
adjusted by a pressure regulator very easily.
Table 7 Advantages of the pneumatic system.
Those advantages illustrate that pneumatic system is more suitable to use, comparing to
other systems.
46
3.3-Disadvantages [9], [10]
All structural systems have weaknesses, unfortunately pneumatic air structures are no
different, the list below illustrates those disadvantages.
Disadvantages Descriptions
-Require qualification It is an old solution so it always requires people
with qualification to deal with it.
-Require preparation Compressed air requires good preparation and
consistent piston speed to operate.
-Connection issues
Not able to communicate with electrical devices or
other machines.
-Loudness
Pneumatic systems are the loudest types of designs
that power machines.
The air comes out very loud so will cause noisy.
The solution is to put a silencer on each dump line.
-Weather durability
Less durable comparing to other systems, due the
moisture the system can freeze especially outside.
-Safety issues
Sometimes pipes that supply the system air have the
ability to move on their own, that will cause damages
to those nearly.
-Easy to condense /moisture
Needs drying to avoid condensation also include
small quantity of lubricant, to minimize frictions in
the actuators and valves.
-Hard to find leaks A seal is required so that air does not leak.
Seal leakage can cause energy loss.
-Environmental suitability Can not work underwater and are sensitive to
vibrations.
-Toxins and chemicals
Sometimes pneumatic systems use hazardous
chemicals to their design, which cause accidental
launches of chemicals into the air, and damage the
environment.
Table 8 Disadvantages of the pneumatic system.
47
3.4-Conclusion
According to the laboratory experience with pneumatic system while working on this task,
I noticed that, it has a simple design which make it suitable for use, also air is available
everywhere in the infinite quantities, and it is transported into pipelines easily, also it was
quite easy to control the speed, but in the other part it required good preparation and
double check to avoid accidents, moreover it is loud system and sometimes pipes which
supply the system air moved by their own which caused damages to those nearly in
addition it was difficult to find leaks.
Expected after knowing the advantages and disadvantages of pneumatics, these losses can
be avoided.
48
Chapter 4-Possible changes to the pneumatic solution
4.1-Possible changes This pneumatic solution has been done with the help of old components, innovation strategy
is about how to use the development of new components to obtain better performance
According to this task, the new components which can replace the old ones, are described
below
The new double-acting cylinder with control cams, End-position cushioning with two
adjusting screws. A permanent magnet is mounted on the cylinder piston, its magnetic field
can trigger a proximity switch.
Figure 26 Flow control valve (linear vs. corner version) [3]
This valve is used to influence the volumetric flow rate through an adjustable throttle point,
in one direction. In the opposite direction, the throttle is bypassed using the non-return
Figure 25 Old and new double acting cylinder [3]
49
valve, one-way flow control valve is a combination of a flow control valve and a no return
valve. The cross-section of the restrictor can be set by means of a knurled screw.
Figure 27 New 5/2 way valve will be used instead of the old one [3]
For innovation purposes, 5/2-way directional valve were used, from the name itself has
5 ports equally spaced and 2 flow positions. It can be used to isolate and simultaneously
bypass a passage way for the fluid which for example should retract or extend a double-
acting cylinder, there are variety of ways to have this valve actuated, a solenoid valve is
commonly used, a lever can be manually twist or pinch to actuate the valve, an internal
or external pneumatic pilot to move the shaft inside, sometimes with a spring return on the
other end so it will go back to its original position when pressure is gone.
Figure 28 PLC S7–200 replaces the quickstepper[3] .
50
Programmable Logic Controller (PLC) is a digital computer used for automation of industrial
processes, such as control of machinery on factory assembly lines.
It is designed for multiple inputs and output arrangements, extended temperature ranges,
immunity to electrical noise, and resistance to vibration and impact.
A PLC is an instance of a hard-real-time system, because output results must be correspond
to input conditions, or other operation will result.
The software used to program the S7 PLC’s is STEP 7-Micro/WIN (as it was mentioned in the
first chapter).
Figure 29 3/2 way roller level valve and the new model [3]
The roller lever valve is actuated when the roller lever is pressed, for example by the cam of
a cylinder, after release of the roller lever, the valve is returned to its initial position by a
return spring, and for the new roller level valve Pressure range is (3.5 to 8 bar) and nominal
flow rate is 1 (P) --> 2 (A) 120 l/min.
51
4.2- Safety conditions for pneumatic system [11]
According to this task some safety conditions must be applied.
-Do not activate compressed air, till all of the tubing connections have been finished and
secured.
-Risk of accident due to tubing slipping off.
-Utilize the short possible tubing connections.
-In the event that tubing slips off, switch compressed air supply off instantly.
-Risk of damage when switching compressed air on, Cylinders may forward and backward
automatically.
-Change compressed air supply off before taking apart the circuit.
-Pneumatic circuit dismantling, Push the blue release ring down, after which the tubing
can be pulled out.
-Pneumatic circuit installation, Relate the devices with plastic tubing.
-Even though the pressure of compressed air in pipes and reservoirs is relatively low, when
the container loses its entirety, fierce explosions may still happen.
-Before switching on a compressed air supply unit, one should thoroughly inspect the
whole circuit to check if there are any loose parts, abnormal pressure or damaged pipes.
-Compressed air released from the exhaust contains particles and oil droplets, this can
cause eyes issues.
-A loose pipe may shake violently due to the high pressure built up inside it. Therefore,
each time before the system pressure is increased, thorough inspection of the entire
circuit is required to avoid accidents.
-Switches should be installed on the compressed air supply unit, to permit speedy and easy
control of air flow.
-In case of a leakage, the compressed air supply unit should be turned off immediately.
-The compressed air supply unit must be turned off before changes can be made to the
52
system, stay clear of the moving parts of the system, never try to move the driving parts in
the mechanical operation valve with hands.
4.3 -Industy 4.0 [12]
Industry 4.0 is the fourth industrial revolution, very useful for this task in order to get
the innovation of the new components.
The present trend of (Automation-data exchange) in industrialization technologies.
It contains:
- Cyber physical systems.
-The internet of things.
-Cloud computing.
This industry 4.0 makes smart factory.
Figure 30 Industry 4.0 environment [12]
4.4 -Design principals [12]
There are 4 main support companies in characterizing and realizing the industry 4.0
scenarios.
1- Interoperability:
The possibility of devices, machines, also people to communicate together through:
-The internet of people (lop).
-The internet of things (lot).
53
2– Information transparency:
The possibility of information systems to make for the physical world a virtual copy
through enriching the models digital plant, with the data of the sensors.
3– Decentralized decision
The possibility of cyber physical systems to make their own decisions and process
tasks independently.
4– Technical aid:
The possibility of aid systems to help human through visualizing the informations.
4.5-Effect of industry 4.0 [12]
It will impact many fields for example:
-IT security.
-Workers.
-Business and services models.
-Socio-economic.
-Industry demonstration.
-Product lifecycle.
-Industry value chain.
-Continuous productivity.
4.6-Conclusion This chapter illustrates the new pneumatic components which can be added to the system to
replace the old ones, this procedure permits the innovation for better performance,
In addition, it describes safety conditions to avoid accidents and achieve an acceptable level
of security, moreover it explains Industry 4.0 (the fourth industrial revolution) which is a new
technology of innovation related to industry 3.0 in order to get better performance.
54
Chapter 5-Possible errors states in the facility and their management 5.1 Introduction [13]
Every pneumatic circuit has a logical sequence of operation that can involve timing logic,
pressure sensing, position sensing, and speed regulation. Troubleshooting is initiated when
the circuit does not operate properly.
The list below illustrates the general possible issues for the pneumatic system.
-Air pressure loss during operation.
-Cylinder noise at power up.
-Slow cylinder speed.
-The actuator ports are plugged with contaminants.
-The system or actuator filter is blocked or clogged.
-Air is leaking at the piston guide bushings.
-The piston seals are leaking.
-The spring return units have broken springs, valve is binding.
-There are problems with the seals.
-Varying or low air pressure.
-Incorrect utilize of flow control.
55
5.2 Possible error states According to this task, those are the common errors and their management
a- Pneumatic cylinder failure usually results from some situations for example:
Possible problem Recommended action
-Operating over component limits.
Operating a cylinder over pressure, load
and/or energy limits can also cause the
components failure.
Include either increasing rod-thread size or
using a studded rod end.
-Insufficient lubrication.
This happens due to leakage of worn
piston seals and/or rings.
Replacement is the only solution.
-Side-load mounting.
Side-load applications do not permit
the piston rod to work in-line while the
extend-retract motion of the cylinder.
This result is seal failure.
Cylinder mountings should be checked on
a regular basis.
-Air pressure loss during operation. Check the ourlet tubing.
-The system fueling up with air, but
when activated, the air is not released.
Clean the area then reactivate the control
level again.
-Cylinder body seal leak.
Loose tie rod, Pinched or extruded seal,
Seal deterioration-hard, brittle, generally
due to temperature extremes.
Repair or replace.
Table 9 Pneumatic cylinder problem and recommended action.
b- Actuator moving abnormally slow [15]
Possible problem Recommended action
-Plugged air silencer, plugged filter. Replace or clean silencer, replace air filter.
-Flow control valve incorrectly adjusted.
Readjust the valve.
-Broken cylinder, seal. Replace cylinder or seal.
-Air leak, squeezed tube. Repair air leak or tube.
Table 10 Actuator moving slow problems and their management.
56
c- Flow control valve [14]
Possible problem Recommended action
-Higher flow rate than normal. Regulate handle stem to obtain desired
output.
-The valve seat warm out or faulty. Change the valve seat installation.
-Not fonction pressure gauge. Change faulty gauge.
-Blocked orifice or piston. Perform again flash of piston or orifice
till the fluid will flows.
-The pressure setting are too close
to that of another valve in the
circuit.
Regulate pressure gauge.
-High oil viscosity. Verify the purity of oil, separator efficiency
also status.
-Restricted orifice. Clean properly the orifice.
- Incorrect adjust valve. Verify the correct installation and regulate
it properly.
Table 11 Flow control valve issues and their solutions.
d- Pressure too low [15]
-Problems -Solutions
-Damaged cylinder pipe, seal or piston. Renew or repair all the damaged parts.
-Incorrectly or damaged adjusted pressure regulator valve.
Replace regulator or readjust rating.
-Directional or other valve open, because of the dirt or failed pilot
circuit.
Locate damaged part, then clean or replace it.
-Plugged filter. Replace filter.
Table 12 Low pressure problems and their management.
57
e- Valve spool stuck
Possible problem
Recommended action
-Valve pilot not functioning Clean or replace piloting part.
-Impurities between spool and sleeve Replace valve.
Table 13 Valve spool stuck issues and recommended actions. f- Contamination in circuit
Possible problem Recommended action
-Improperly filtered feed pipes Evaluate circuit design, consider adding pre-filters.
-Burrs inside piping components Components or/and piping not well protected during maintenance, and/or storage, disconnect cylinder from pipes
and remove burrs.
-Usually excessive dirt in circuit Wipers not used on cylinders where
necessary, evaluate circuit design,
consider adding wipers to cylinders.
Table 14 Contamination in circuit problems and solutions.
5.3- Conclusion This chapter illustrates the pneumatic system common issues and their solutions,
According to my experience while doing this task at the laboratory, i understood that
solving a pneumatic system problem take the several steps:
-Visually inspect the system, and have a thought understanding of this system, using a
schematic, then operate the system and recheck all services.
-Next step isolate the subsystems, and make a list of possible causes in order to reach
a conclusion about the problem.
-Final step is testing the conclusion then repairing or replace as necessary.
Periodic maintenance is the best solution to keep the greatest performance.
58
Chapter 6-Final Conclusion
6.1-Conclusion In this master thesis, I have successfully made in:
Chapter1 analysis of current pneumatic system according to the facility sketch, and the given
pneumatic system circuit, so two pneumatic circuits were created in fluidsim (with and without HMI)
with visual function of the state diagram in the fluidsim as well).
Chapter2 elecropneumatic circuit was made as a prepation for Virtual PLC solution, also
implementation of graphical language (GRAFCET), then a real PLC Solution was presented for PLC
SIEMENS SIMATIC S7-200 using STEP 7-Micro/WIN software (ladder diagram).
Chapter3 description of the advantages and disadvantages of this solution.
Chapter4 as a part of innovation, designs the possible changes to this pneumatic components in
nowadays were presented.
Chapter5 description of the possible error states at the facility and their management.
Chapter 6: includes all references, list of abbreviation, and appendix.
59
6.2- References Chapter 1, 2
[1] Fluidsim library
[2] Means of automatic control subject files
[3] http://www.festo-didactic.com/int-en/learning-systems/equipment-
sets/pneumatics/components/?fbid=aW50LmVuLjU1Ny4xNy4yMC41NjQ
[4] Electro-Pneumatics M1 Student - Quia
[5] https://en.wikipedia.org/wiki/Programmable_logic_controller
[6] http://www.plcacademy.com/siemens-s7-200
[7] FLUIDSIM 4.0 Contents
[8] CTU laboratory components
[16] https://en.wikipedia.org/wiki/Sequential_function_chart
Chapter 3
[9] http://ie35int.blogspot.cz/2013/05/the-advantages-and-disadvantages-of.html
[10] http://www.ekci.com/benefits-and-disadvantages-of-pneumatics.html
Chapter 4
[11] http://www.festo-didactic.com/ov3/media/customers/1100/567266.pdf
[12] https://en.wikipedia.org/wiki/Industry_4.0
Chapter 5
[13] http://www.pneumatictips.com/4185/2015/10/pneumatic-equipment-
components/pneumatic-system-guidelines-for-success/
[14] http://www.valve-world.net/pdf/maintaining_CASEI.pdf
[15] http://www.valmet.com/media/articles/up-and-running/RTPneuTrouble/
60
6.3-List of abbreviation
-PLC: Programmable Logic Control.
-HMI: Human Machine Interface.
-NC: Normally Closed.
-NO: Normally Opened.
-PN: Petri Net.
-SDD: Step Displacement Diagram.
-LAD: Ladder Logic.
-STL: Instruction List (IL) in Siemens PLC’s, called Statement List.
-FBD: Function Block Diagram.
- (SFC): Sequential function chart.
-MCR: Master Control Relays.
-PMA: Pneumatic Motor A.
-PMB: Pneumatic Motor B.
-PMC: Pneumatic Motor C.
61
6.4-Appendix
Pneumatic components (1) Single acting cylinder. (2) Cross section of a single acting cylinder.
Figure 31 Single acting cylinder. (1) Double acting cylinder (2) Cross section of a double acting cylinder
Figure 32 Double acting cylinder.
(1) 5/2 Directional control valve (2) Cross section (3) Pneumatic symbol
Figure 33 5/2 Directional control valve. (1) Shuttle valve (2) Cross section (3) Pneumatic symbol
Figure 34 Shuttle valve.
62
Figure 35 Cross section of a double acting cylinder.
Figure 36 PLC Siemens Simatic S7-300, 1200, 1500.
63