Conveyor Belt controller

Abstract: - in almost all the manufacturing industries where ever there is a complete assembly line automation like bottling plant, chemical industries, food processing and packaging industries a conveyor belt is ultimate and widely used option. The entire process is carried on single (or multiple) conveyor belt(s). From start to end the items are moving on belt and the processes are done in between, while they are moving.

Just take an example of any bottling plant then in this case the bottles are moving on belt one by one and at one place they are filled, at another place they are sealed, then labeling and finely packaging in a bunch on 10, 20 or 50 like wise. This whole process runs on single conveyor belt.

So here I am explaining one such conveyor belt application. I am taking simulated conveyor belt from multisim 10.0 software to explain this application. In this example at a time only one box moves on belt it is filled with items at the middle of belt and then it moves forward. When it passes through belt another box is available for filling. So actually its very simple application and it illustrate the demo of actual conveyor belt.

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Let us first see various controls for this conveyor belt so that we can get better idea that how to control it.

As shown in above figure there is a motor that rotates the belt. Various sensors are placed on belt to sense the position of moving container. Various controls are available for motor

Forward - when it is applied positive pulse the motor will start rotating clockwise and the container on belt will move ahead

Reverse - when it is applied positive pulse motor will start rotating anticlockwise and the container will move back

Stop - when it is applied positive pulse motor will stop and container will be steady

Speed - this will change the speed of belt as the voltage applied to this pin is varied from 0 - 5 V

One more control is drop

Drop - the items will drop from the nozzle till this is applied high logic (5V)

So all above are the inputs of this conveyor belt system. Now let us see the outputs. There are four outputs and they are from various sensors placed on belt.

Sensor 1,2 & 3 o/p - it gives high output as container reaches to it.

Sensor 4 o/p - it generates positive pulses as items dropped from nozzle.

So depending upon this input and output we have to design a circuit that will control this conveyor belt. Let us first see the block diagram of system

Because this very small system we don't require more input output pins. So we are using 20 pin 89C2051 micro controller. As shown in figure there are inverters, buffers, indicators and a 2 digit counter, the building blocks of the system

89C2051 - it performs following tasks.

• It controls the belt motor by giving fwd and stp pulses.
• Also it gives drop command to fill the container.
• It counts no of items in container and resets the counter with every new container.
• Indicates different actions on LEDs

Inverters - it inverters the positive pulses into negative pulses

Buffers - it provides isolation between digital system (micro controller) and analog system (conveyor belt)

2 digit counter - it counts no of items filled in container up to 99 only

LED indicators - it indicates various events currently going on

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