Programmable Logic Controllers
2. PLCs
Now let's shift gears and talk about PLCs. These are the unsung heroes of the industrial world. A PLC, or Programmable Logic Controller, is a specialized computer used to automate industrial processes. Unlike your desktop PC, a PLC is designed to withstand harsh environments — think extreme temperatures, vibrations, and electrical noise. They are built tough, specifically because they will be placed in tough environments.
PLCs excel at executing control logic in real-time. They monitor inputs from sensors (like temperature probes or pressure gauges), process that information according to a pre-programmed set of instructions, and then generate outputs to control actuators (like motors, valves, or pumps). This all happens continuously, often in milliseconds or even microseconds. It is a controller that needs to be on all the time, and must be rugged enough to live in harsh environments.
The programming language for PLCs is often ladder logic, which is a graphical language that looks like electrical schematics. This makes it relatively easy for electricians and technicians to understand and maintain the control system. There are also other programming languages you can use like Function Block Diagrams, Structured Text, Instruction List, and Sequential Function Charts.
Imagine a bottling plant. PLCs are responsible for coordinating the entire process, from filling the bottles to capping them, labeling them, and moving them down the conveyor belt. It is truly the workhorse of the automation world.
