Assessing Industrial Controller Options

It’s been a little more than 50 years now since the invention of the programmable logic controller, or PLC. And though PLCs are essentially very basic computers used to control machine functions, they allow engineers to develop, modify, and expand the functionality of control systems through software, rather than hardware changes to the system that were required in the past with electromechanical relays. This capability really set the stage for the future of automation and control and many of the advances we’re seeing today. But just as no technology is static, neither is the PLC. Over the years, suppliers added new capabilities to basic PLCs to address various end user needs. Some of these new functionalities included integrated servo and drive control, network communications, advanced process control, and the ability to handle multiple programming languages. With all these new capabilities, the PLC became more than just a basic controller, and that’s how the term programmable automation controller—or PAC—came into being. Basically, this term better reflects the expanded—and still expanding—capabilities of controllers.