TIMBER MILL CONTROLLER
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Joined: Jun 2010
08-10-2010, 04:47 PM
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TIMBER MILL CONTROLLER
Today world is looking for efficient and accurate mechanism to control industrial operations. Timber mill is such an industry. There heavy woods are placed on a platform on a rail to move it through the running saw. A worker will drive a steering to move the platform along the rail. The forward and reverse direction of the platform is depending on the direction of the steering. It is totally a mechanical and manpower consuming process.
Here an electronic system is introduced to manage the platform on the rail. This will eliminate the use of manpower and provides more accuracy. An electric motor is used to drive the platform. By controlling the power to the motor the operator can control the speed and movements of the platform. The direction of the motor controls the direction of the platform. Operator can manage it with a single switch.
Digitizing the interface, power electronic control for electrical control and motorizing the drive are the main ideas used for building a timber mill controller. In advanced technology equipments feather touch switches using for human machine interaction. In this project and implimentation three switches used are in this type. To increase to decrease and to reset the speed of the motor this type of switch is used. A monostable multivibrator is used to prevent the false trigger of switch.
An up-down counter will manage the increment and decrement of the motor speed. A pulse on the up counter input the counter increments its four bit binary output. The down counter decrements the same output when it receives a pulse. That means the four bit binary value decides the speed of the motor.
An AC motor is used to control the rail platform. To control the speed of the motor a solid state circuit is used. By varying the firing point of AC cycles, the power in a circuit can be controlled. Four firing circuit are used to achieve four different firing points. Each has a RC circuit which determines the time to trigger.
A selector circuit will enable one out of four firing circuit according to the data from the up-down counter.
A relay circuit is also there to control the direction of the motor. The direction change is achieved by changing the polarity of the winding of the motor.