ABSTRACT
Control Strategies Automation systems employ multiple strategies to accomplish the control functionality using various available hardware and software technologies depending on the need and other economic considerations. The end result is achieved by a set of hardware components made functional by programming software. The two main control system strategies or technology frameworks and their components are:
Programmable Logic Controllers (PLCs). Earliest automation and control technology was based on relay control circuits. PLCs were found as a replacement for relay control circuits by providing flexible capabilities such as reprogrammable units. A typical PLC consists of a microprocessor, memory, input/output circuits and terminals, and a programming interface. Memory is usually battery-backed in order to avoid losing a program during power loss. PLCs are still preferred over other options for many types of process control applications due to their high reliability even in extreme industrial conditions.
