A Programmable Logic Controller generally has a set of input and output ports to which the external peripherals are connected, which are to be electrically controlled by the PLC. Looking into the flow of working with the PLC, the processor tries to make decisions in accordance with the program, generally written by the user using some logic used to program these units. Some of these logics include Function Block Diagram, Ladder Diagram, Structured Text, Sequential Function Chart and Instruction List.
The objective is to create an Open Source PLC, which has the capabilities of the industrial PLC, but the catch here is, it’s much affordable and simpler to work with. It incorporates a development board, that works on AVR’s ATmega16A IC, giving up to 40 pins, most of which can be used and programmed as the Input-Output pins as it’s done on a PLC. Moreover, the logic used here is Ladder Logic which is one of the easiest and also, robust in terms of its efficiency. The main point here is, this device is a standalone device, which can work without the host system being there, just being powered by a source. HEX files to be generated according to the controller are generated by a software called LDMicro, freely available for Windows and Linux users alike. The programming on the board is done via an USB-ASP device through ISP headers. All the processor wants now is a code to be dumped on it to start automating your small needs.
This prototype will be helpful for students to get the feel of working with the PLCs, to control small automated systems. It’ll also be easy as there’s no coding involved and it’s using a GUI that is user-friendly and also efficient. Along with the development board, which can be used as microcontroller too, there are various hardware modules to start off with and later the students can come up with their own hardware setups and test their modules, with the board. It’s really versatile as it can suit your microcontroller needs and also work as a PLC. All you need is the HEX code from LDMicro for your desired usage with hardware. The OpenPLC setup is shown below: