MICROPROCESSOR CONTROL SYSTEM
A microprocessor is a small computer on a single integrated circuit containing memory and programmable input/output channels. The first general-purpose microprocessor, the 4004, was designed by Intel Corporation of Santa Clara, California USA. Released in 1971, it was based on ideas from the 1969 paper “The Computer as a Communication Device” by Gordon E. Moore and co-workers at Electrical Engineering Department of Stanford University. It contained 2,300 transistors and had a clock frequency of 740 Hz.
Microprocessor are essential for many of the products we use every day such as TVs cars, radio, home appliance, and computers. Microprocessor based controls also called microcontrollers. Microcontroller is a digital integrated circuits which serves as a heart of many modern control applications.
Microprocessor and Microcontrollers are similar but the architecture of the both differs in the applications domains. microprocessor are employed for high speed applications such as desktop and laptop computers whereas the microcontroller are employed in automations and control applications such as microwave ovens, automatic washing machines, dishwashers, engine management system, DVD players etc.
Microcontrollers are embedded inside some other devices so that they can control the features or actions of the product. therefore , it is also called embedded controller.
A microcontroller generally has the main CPU core, ROM / EPROM / RAM and some accessory such as timers , pulse width modulators, A/D converter and I/O controller all integrated into one chip, microcontroller is a computer on a chip that is programed to perform almost any control, sequencing , monitoring, and display function.
EXAMPLES OF MICROPROCESSOR CONTROL SYSTEM:
AUTOMATIC FILM CAMERA:
the automatic camera using film has the features of automatic focusing and exposure. the basic elements of the microprocessor based control system used in as automatic film camera for focusing and exposure. The working of auto focusing aperture control for auto-exposure is explained as follows.
The auto focusing is achieve by using range sensor. when the system is switch on to activation mode,the camera is pointed at the object to take the snap. the microprocessor takes the input signal from the range sensor. this signal is processed to send the output signal to the lens position drive to move the lens for achieving auto focusing. The microprocessor gets the feedback signal about the lens positions from the range sensor which is the used to modify the lens positions to get the desired position of focus.
APERTURE CONTROL FOR AUTO EXPOSURE:
The light sensor is used to achieve an aperture control for auto-exposure. when the shutter switch is pressed to the initial position , the microprocessor calculates the shutter speed and aperture settings based on the input from a light sensor. it the gives output signal to the viewer finder. when the shutter switch is pressed to the final position, the microprocessor gives signal to the aperture control drive to open the shutter to the required position. the shutter is kept open for the preset amount of time and then it is closed. after photograph has been taken, the microprocessor sends an output signal to the motor drive to advance the film for the next snap.