PC Based Supervisory Control And Data Acquisition System

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ABSTRACT
The aim of the project is to read the status of industrial machines which is connected to 8 channel ADC by sensors. It will send the readings of ADC as a message through MAX 232 to PC.

One of the 8051s many powerful features is its integrated UART, otherwise known as a serial port. The fact that the 8051 has an integrated serial port means that you may very easily read and write values to the serial port. If it were not for the integrated serial port, writing a byte to a serial line would be a rather tedious process requiring turning on and off one of the I/O lines in rapid succession to properly "clock out" each individual bit, including start bits, stop bits, and parity bits.

However, we do not have to do this. Instead, we simply need to configure the serial ports operation mode and baud rate. Once configured, all we have to do is write to an SFR to write a value to the serial port or read the same SFR to read a value from the serial port. The 8051 will automatically let us know when it has finished sending the character we wrote and will let us know whenever it has received a byte so that we can process it. We do not have to worry about transmission at the bit level which saves us quite a bit of coding and processing time.

In this project, we are using three sensors, a relay, ADC (Analog to Digital Conversion), Microcontroller. By using this project, one can control the operation of the machines depending on the readings of TEMPERATURE, VOLTAGE, CURRENT by means of PC using PC’s hyper terminal window.

This project uses regulated 5v, 500mA power supply. 7805, a three terminal voltage regulator is used for voltage regulation. Bridge type full wave rectifier is used to rectify the ac output of secondary of 230/12v step down transformer.