The document describes a traffic light control system using Programmable Logic Controllers (PLCs). The system uses three PLCs - a master PLC that controls two slave PLCs. The master PLC sends commands to control the light patterns at an intersection. The slave PLCs control the lights for cars and pedestrians. The system was prototyped using a PCB, 3D printed traffic lights, and packaging to test the logic implemented on the PLCs.

1. Industrial and Automation System 2016
1

2. Our Goals
2
The final target is to design a PLC controller
in order to:
● Perform a simulation of a control of a
traffic light road system;
● Learn the use of Twido PLC model
TWDLCAA16DRF;
● Learn the use of TwidoSoft software.

3. History: a traffic light system
3

4. 4
Programmable Logic Controller (PLC)
Characteristics:

5. 5
Programmable Logic Controller (PLC)
Characteristics(2):

6. 6
PLC: Block Diagram

7. 7
Twido PLC: Power Supply
● The Phase and Neutral references
have been connected to the
electrical system from 100 to 240
Vac.
● The ground connection in general
will not be connected to anything
because the PLC itself already has
an electrical reference.

8. 8
Twido PLC: Input
Three distinct and separate
regions:
● The first two contacts, DC OUT,
provide an internal power supply
of +24V at 150 mA and another
one of 0 Vcc, used to power the
inputs or outputs;
● The third contact, DC IN, is used
to supply the inputs and
determine the Positive or
Negative logic;
● The remaining 9 contacts (0 to 8)
connect various inputs device;

9. 9
Twido PLC: Output
Three distinct and separate regions:
RED: Locate the contacts of outputs 0 to
3;
GREEN: Locate the output contacts 4
and 5;
BLUE: Locate the output pin 6.
Ry COM0, 1 and 2 are used, by connecting
a power supply, to power corresponding
outputs.

10. 10
Twido PLC: at the top
Status LEDs :
● Input (0 to 8)
● Output (0 to 6)
● Run
● Power
● Error

11. 11
Twido PLC: Interfacing

12. 12
TwidoSoft: Main window

13. 13
TwidoSoft: Ladder Viewer window

14. 14
TwidoSoft: Ladder Editor window

15. 15
Traffic Lights Control System(TLCS)
prototype
Thanks the support of
Fablab Messina we created
a prototype of TLCS that
we used in combination
with the PLC.
This prototype allow us to
give an output to the logic
implemented by using the
PLC.

16. 16
Main Activities
(1) PCB (printed circuit board): design and creation
(2) Traffic Lights: design and creation
(3) Packaging: design and creation
(4) Final Prototype: assembling and testing

17. 17
(1)PCB (printed circuit board): design and
creation
PCB design with KiCad-EDA
convert Kikad-EDA to TIFF
setting laser cut software tool
painting of the copper plate
laser cutting of the painted copper plate
engraving the copper plate with the FeCI3
cleaning the copper plate with a solvent
making holes on the final PCB
component soldering on the final PCB

18. 18
PCB design with KiCad-EDA
KiCad-EDA (http://kicad-pcb.org/ ),
a cross platform and open source
electronics design automation suite

19. 19
convert Kikad-EDA to TIFF

20. 20
setting laser cut software tool
Software's Graphical User
Interface that controls the
laser cutting tool.

21. 21
covered the copper plate using black paint

22. 22
laser cutting of the painted copper plate

23. 23
engraving the copper plate with the FeCI3
To engraving the copper
plate, we used a corrosive
liquid, the ferric chloride
(FeCl3), often inaccurately
called "acid."
We put the ferric chloride in
a plastic container and we
immersed the copper plate
for some minutes.

24. 24
cleaning the copper plate with a solvent

25. 25
final PCB

26. 26
making holes on the final PCB

27. 27
component soldering on the final PCB

28. 28
(2) Traffic Lights: design and creation
Traffic Light design with Tinkercad
Traffic Light 3D printing session
Making holes on the Traffic Light 3D printed

29. 29
Traffic Light design with Tinkercad
Tinkercad is a simple,
online 3D design and 3D
printing app for everyone.
https://www.tinkercad.com/

30. 30
Traffic Light 3D printing session
Then we did two 3D
printing sessions. Each
session we printed two
Traffic Light.
The duration of the single
3D printing session was 2
hours and 10 minutes.

31. 31
making holes on the Traffic Light 3D
printed

32. 32
attach diode LEDs inside each Traffic Lights
printed

33. 33
(3) Packaging: Design and Creation
Packaging design of the TLCS prototype
Record a sheet of plexiglass using the laser cutting tool
Cut a sheet of polycarbonate using the cutting tool

34. 34
packaging design of the TLCS prototype

35. 35
record a sheet of plexiglass using the laser
cutting tool

36. 36
cut and engrave a sheet of polycarbonate
using the cutting tool

37. 37
(4) Final Prototype: assembling and testing
Assembly all the components to create the final packaging
Solder wires with the PCD and testing phase.

38. 38
assembly all the components to create the
final packaging

39. 39
Solder wires with the PCD and testing
phase

40. 40
Traffic Lights Control System(TLCS)
prototype
See you in Rome next October !!!

41. 41
TLCS I/O prototype interface
GND 5VNULL
back
pedestrian
sx
pedestrian front

42. 42
Architecture
2
1
34

43. 43
Architecture: Three PLC System

44. 44
Logic connections between master and slaves PLC
Master Slave 1 outputs Slave 2 outputs
000 → OFF state
001 → Night state 1* , 4*
010 → Red A, Green B 0, 5, 6 4, 0, 3
011 → Red B, Green A 3, 2 6, 2, 1, 5
100 → Yellow A, Red B 1, 3 1**, 2, 5**, 6
101 → Yellow B, Red A 4, 0, 6** 3**, 0, 4
110 → Sunday (LTZ)
Green B
6 4,0,3
111 → Sunday (LTZ)
Green A
5, 6, 2,1
only bicycle and pedestrian
traffic without yellow state
**: Lamp %S5 time base 100 msecs
LTZ: Limited Traffic Zone.
*: Lamp %S6 time base 1 sec

45. Master PLC
● %Q0.0, %Q0.1, %Q0.2:
command bit.
● %Q0.3: buzzer n. 1.
● %Q0.4: buzzer n. 2.
● %Q0.5: buzzer n. 3.
● %Q0.6: buzzer n. 4.
45
● %I0.0 Input to enable Daytime mode
● %I0.1 Input to enable Sunday mode
● %I0.5 reservation Push Button n. 1
● %I0.6 reservation Push Button n. 2
● %I0.7 reservation Push Button n. 3
● %I0.8 reservation Push Button n. 4

46. 46
15 secs 5 secs 10 secs5 secs
Block Diagram for Daytime behavior
crossroad A/B

47. Daytime Mode
47

48. 48
Master PLC - DRUM Programmer
000 configuration - all led are
switched off.
Reset leds during scenarios
variation.
DayTimeno-Sunday
Red A, Green B
Yellow B
Red B, Green A
Yellow A
every 5 secs

49. 49
Nighttime Mode
001 → Night state
NightTimeno-Sunday
A-B Direction

50. 50
Reservation Mode
simulate button push along B Direction
simulate button push along A Direction
buttons n. 2 - 4
buttons n. 1 - 3

51. 51
Reservation Mode
Green B AND Reservation B Direction
Green A AND Reservation A Direction
buzzer n. 2
buzzer n. 4
buzzer n. 3
buzzer n. 1

52. 100 → Yellow A, Red B
52
Reservation Mode
direction A - pedestrian reservation
0.5’’

53. 53
101 → Yellow B, Red A
direction B - pedestrian reservation
0.5’’
Reservation Mode

54. 54
Sunday Mode
Time base: 1 min
1
1
0
1
1
1
110 Green B
111 Green A
30 secs
30 secs

55. 55
Architecture of Slaves PLC
Output PLC Slave 1 PLC Slave 2
0 RcA RpA
1 YcA GpA
2 GcA RpB
3 RcB GpB
4 YcB RbA
5 GcB GbA
6 GbB RbB
Where:
● RcA, RpA, RbA are respectively the red lights of car, pedestrian, bicycle
in A direction;
● GcA, GpA, GbA are respectively the green lights of car, pedestrian, bicycle
in A direction;
● RcB, RpB, RbB are respectively the red lights of car, pedestrian, bicycle
in B direction;
● GcB, GpB, GbB are respectively the green lights of car, pedestrian, bicycle
in B direction;
● YcA, YcB are respectively the yellow lights of car along A and B direction;

56. 56
Slave 1 PLC
● %I0.0, %I0.1, %I0.2 Input coming from
the output of Master as command
001 → Night state
010 → Red A, Green B
011 → Red B, Green A
100 → Yellow A, Red B
101 → Yellow B, Red A
110 → Sunday Green B
%Q0.0,
%Q0.1
%Q0.2
%Q0.3
%Q0.4
%Q0.5
CAR along A-B direction
%Q0.6
A
B
B

57. 57
COMMAND 010
TURNONTURNOFF
Slave 1 PLC - Red A, Green B

58. 58
COMMAND 101
TURNONTURNOFF
Slave 1 PLC - Red A, Yellow B

59. 59
COMMAND 011
TURNONTURNOFF
Slave 1 PLC - Red B, Green A

60. 60
COMMAND 100
TURNONTURNOFF
Slave 1 PLC - Yellow A, Red B

61. 61
TURNONTURNOFF
COMMAND 001
0.5’’
Slave 1 PLC - NightTime

62. 62
TURNOFF
COMMAND 111
Slave 1 PLC - Sunday Time, Reset

63. 63
TURNOFF
COMMAND 110
TURNON
Slave 1 PLC - Sunday Time

64. 64
Slave 2 PLC
● %I0.0, %I0.1, %I0.2 Input coming
from the output of Master as
command
010 → Red A, Green B
011 → Red B, Green A
100 → Yellow A, Red B
101 → Yellow B, Red A
110 → Sunday Green B
111 → Sunday Green A
%Q0.0
%Q0.1
%Q0.2
%Q0.3
Pedestrian lights
%Q0.4
%Q0.5
%Q0.6
A
B
A
B

65. 65
COMMAND 010
TURNONTURNOFF
Slave 2 PLC - Red A, Green B

66. 66
COMMAND 101
TURNONTURNOFF
Slave 2 PLC - Red A, Yellow B
0.05’’

67. 67
COMMAND 011
TURNONTURNOFF
Slave 2 PLC - Red B, Green A

68. 68
Slave 2 PLC - Yellow A, Red B
COMMAND 100
TURNONTURNOFF
0.05’’

69. 69
Slave 2 PLC - LTZ, Green B, Red A
COMMAND 110
TURNONTURNOFF

70. 70
Slave 2 PLC - LTZ, Green A, Red B
TURNONTURNOFF
COMMAND 111

71. 71
GRAZIE PER L’ATTENZIONE