A Programmable Logic Controller (PLC) is a special computer device for industrial control systems. Due to its rugged construction, special functional features (such as sequential control, counters and timers), ease of programming, reliable control capabilities, and ease of hardware use - the PLC is not only used in the field of specialized digital computer control systems in industry and other fields. Most industries abbreviate these devices as "PC", but it is also used for personal computers; therefore, many manufacturers name these devices as PLCs.
Programmable Logic Controllers are used not only for industrial purposes, but also for residential applications such as washing machines, elevator operation and traffic signal control. There are a large number of different types of PLCs available in today's market from a large number of manufacturers, so in the following paragraphs, let's learn the basics, principles and applications of programmable logic controllers.