Automation
Programable Logic Controllers
Before programmable logic controllers (PLCs) became the standard in industrial automation, factories relied heavily on relay-based control systems. These systems used electromechanical relays to open and close circuits, creating complex logic sequences to operate machines. In large manufacturing environments, these relays could span entire walls, forming what is often referred to as a “relay wall.” Troubleshooting was a major challenge, as each individual relay was hardwired into the control system. When something malfunctioned, technicians had to manually inspect wires, terminals, and contact points to identify the issue, often a time-consuming and error-prone process.
However the creation of the PLC solved all these issues with relay logic. A PLC consists of a CPU (Central Processing Unit) and input and output IO module cards. The CPU is the computer of the system processing information from the input cards.
Human Machine Interfaces
Human Machine Interfaces (HMIs) play a vital role in automated systems by serving as the bridge between the operator and the machinery. An HMI allows a person to monitor, control, and interact with processes managed by a Programmable Logic Controller. It acts as a dedicated computer, often running a specialized operating system, and may come in various forms such as touchscreens, flat-panel displays with buttons, or even portable units.
