An Alternative Option to Commercial Programmable Logic Controllers

The Programmable Logic Controllers (PLC) are widely used in control of Industrial Processes and Machinery. Numerous companies like Mitsubishi, Siemens, ABB, and Omron have developed commercial PLC’s and have launched them in the market. The buyer has to pay a considerable amount to buy commercial PLC’s available in the market. In this paper an AVR Microcontroller Based Circuitry is introduced that can be used as an alternative to commercial PLC’s. Only higher versions of Programmable Logic Controllers contain analog input module. The developed Microcontroller based PLC can also provide a control for analog input signals. This alternative PLC is developed at a fraction of cost to PLC’s available in the market. The controller circuitry is programmed with the help of personal computer software. The LD-Micro Freely available Ladder Logic Programming Software is used to develop the code for the developed Programmable Logic Controller.