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  • Publicado : 28 de agosto de 2012
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The objective of PIC16F84A Based pH Controller is to control the pH of the solutions at different stages of the tanning process ofleather. The PIC 16F884A is a low cost, high-speed microcontroller with internal EEPROM. The PIC 16F84A is a RISC microcontroller consisting of only 35 instructions, which makes programming taskeasier.

The fig (1) shows the block diagram of PIC 16F84A microcontroller based pH controller. It consists of a mc PIC 16F84A, ADC, DAC, Buffer and latches. A 3-to-8 decoder selectsthe buffers and latches. LEDs are provided for indication. The system can be programmed using any personal computer. The communication between PC and microcontroller is established through RS232Cstandard serial cable. The internal memory of the controller can be programmed by PC. Once the system is programmed the EEPROM retains the information for even 40 years and so the system can workindependently.


The system consists of PIC16F84A Microcontroller as CPU, Keyboard and Display section, signal conditioning circuits for sensing current and ADC, output Driversfor LED Display. The current is sensed and is passed through signal conditioning circuits, which consists of shunt Resistance, Transformer, Rectifier and Filter circuits. After signal conditioning thesignal is fed to ADC and then its output is given to the PIC16F84A Microcontroller. The microcontroller reads the digital values from the ADC and the signals are sent accordingly to the LEDs,depending on the pH Value. The system is very fast acting and hence correct pH value can be sensed for proper Tanning of leather and other industrial purposes.Block diagram of PIC16F84A Microcontroller based digital PH controller

Power on


PC Interface


Serial Cable

RS- 232C...
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