PROJECTS

FOUR WAY TRAFFIC CONTROL BY USING PLC

Technicalhub June 30, 2019 no Comments

OVERVIEW:

The project is based on industrial automation and deals with how industries are automated. The software and the hardware are the two important areas in our project. The software deals with the program required to automate the industry.

HARDWARE DESCRIPTION:

In our project, we used ALLEN-BRADLEY PLC MICRO LOGIX 1400 for controlling the outputs by using the input signal.

SOFTWARE DESCRIPTION:

There are 5 programming languages which are used for the programming a PLC.

The list is as follows:

1. Functional block diagram

2. Ladder diagram

3. Structure text

4. Instruction list

5. Sequential flow chart

Out of these five languages, Ladder diagrams is most widely used program because it is simple and easier to understand among all other languages. So we choose ladder diagram program for our project.

HARDWARE REQUIREMENT SPECIFICATION:

SMPS:

As PLC works on 24v dc supply we should use SMPS (SWITCHING MODE POWER SUPPLY) to convert 230V AC to 24V DC. From this we can understand that by using low power we are able to control a huge amount of power that is used to run a huge machines in industries.

PLC:

PROGRAMMABLE LOGIC CONTROLLER which is a brain of the industries. Basically it is being given command using a programming language such as LADDER DIAGRAM. It receives the input from sensors or manual switches for activating the output.

RELAYS:

Definition: The relay is the device that opens or closes the contacts to cause the operation of the other electric control. It detects the intolerable or undesirable condition with an assigned area and gives the commands to the circuit breaker to disconnect the affected area. Thus protects the system from damage.

Working Principle of Relay:

It works on the principle of an electromagnetic attraction. When the circuit of the relay senses the fault current, it energises the electromagnetic field which produces the temporary magnetic field.

This magnetic field moves the relay armature for opening or closing the connections. The small power relay has only one contact, and the high power relay has two contacts for opening the switch.

The inner section of the relay is shown in the figure below. It has an iron core which is wound by a control coil. The power supply is given to the coil through the contacts of the load and the control switch. The current flows through the coil produce the magnetic field around it.

Due to this magnetic field, the upper arm of the magnet attracts the lower arm. Hence close the circuit, which makes the current flow through the load. If the contact is already closed, then it moves oppositely and hence opens the contacts.

APPLICATIONS:

1. Relays are used for isolating a low voltage circuit from high voltage circuit.

2. They are used to control multiple circuits.

3. They are also used as automatic change over.

4.Microprocessors use relays to control a heavy electrical load.

5. Overload relays are used for protection of motor from overload & electrical failure.

MCB (miniature circuit breakers):

A miniature circuit breaker (MCB) automatically switches off electrical circuit during an abnormal condition of the network means in overload condition as well as faulty condition. Nowadays we use an MCB in low voltage electrical network instead of a fuse. The fuse may not sense it but the miniature circuit breaker does it in a more reliable way. MCB is much more sensitive to overcurrent than fuse. Handling an MCB is electrically safer than a fuse. Quick restoration of supply is possible in case of a fuse as because fuses must be re-wireable or replaced for restoring the supply. Restoration is easily possible by just switching it ON. Let’s look at the working of the miniature circuit breaker.

APPLICATIONS:

The very basic use of MCB is that it is used to protect a circuit (wiring, connected load and equipment etc.,) in case of:

Short Circuit
Over Current
Over Load

ALLEN BRADLEY-1400

PLC:

The CPU combines a microprocessor, an integrated power supply, input and output circuits, built-in PROFINET, high-speed motion control I/O and onboard analogue inputs in a compact housing to create a powerful controller. After downloading a program, the CPU contains the logic required to monitor and control the devices in the application. The CPU monitors the inputs and changes the output according to the logic of the user’s program. The CPU provides a PROFINET port for communication over a PROFINET network.

We can connect input and output port in 2 methods i.e.

Input-sinking: output- sourcing
output-sinking: input- sourcing

Sinking: Connecting 0v as common to PLC

Sourcing: Connecting 24v as common to PLC

POWER FLOW:

TECHNICAL SPECIFICATIONS:
PLC Manufacture: ROCKWELL AUTOMATION

Input supply: 230v ac

Input to PLC: 24v dc

SOWTWARES USED:

RS LINX CLASSIC: used to establish communication to PLC.

RS LOGX 500: used to write program.

RS EMULATOR 500: used to simulate program.

Steps to AUTOMATE:

1. Turn on PLC and Change the mode into static mode.

2. Configure the PLC’s IP address.

3. Open RS LINX CLASSIC and verify if we are connected to PLC

4. Now if we are connected then continue to write program as required by using

RS LOGIX – 500.

5. After writing the program compile for error.

6. If there are no error’s then start downloading your program to PLC. The program is transferred from PC to PLC through Ethernet Communication.

7. Accept permissions to go to online. By going to online one can able to force on or force of through software.

PROGRAM MING STEPS

1. Open RX.LOGIX 500 then go to FILE and click new.

2. Select the processor type from popup menu (BUL.1766 MICROLOGICS 1400 SERIES A).

3. Now the programming window gets open.

4. Write your code in the program window by using timers, counters, memory, arithmetic blocks.

5. For our four way traffic light control project we used 12outputs and 2 inputs.

6. Take 2 inputs and 12 outputs according to our requirement.

7. The next 7 Rungs we have timers used to turn on and turn off the 12 outputs.

8. Code for our project is shown below.

9. The first four Rungs of the code denotes how RYG lights work at junction

10. Later on taking 8 timers we are going to construction

SCADA:

We can overcome the disadvantage of monitoring is obtained through SCADA.SCADA is a powerful tool for monitoring and to control from control room itself. So it is implemented almost in every industry due to its advantage and application. To work with SCADA we should interface our PLC to SCADA by taking the same input and output addresses in SCADA software. LADDER DIAGRAM PROGRAM FOR PLC: