Micro Controllers Vs PLCs

On the surface, microcontrollers and PLCs look like they can basically do the exact same things, right? We feed an input, a program does things, and we get an output. They work continually and quickly, acting in milliseconds and faster than a traditional computer could. Why is there such a vast price difference? Why choose the more expensive option?   Certifications Programmable Logic Controllers are nearly  custom built for their industries. There are a myriad list of testing and certification processes for these products. There are extensive engineering processes to prove “XYZ is physically impossible with this product.” This is all to meet workplace safety and keep the facility running with as little down time as possible. For example, we checked the documentation for a random PLC in our inventory, and it had the following ‘general’ certifications: IEC 60068-2-14, 60068-2-1, 60068-2-2, 60068-2-14, UL840, MIL STD 810C method 514.2, EC60068-2-6, JIS C60068-2-6, MIL STD 810C Method 516.2, IEC 60068-2-27, JIS C60068-2-27, NEMA ICS 3-304, EN 6100-4-2, EN 6100-4-3, EN6100-4-4, EN 6100-4-5, EN 6100-4-6, EN 6100-4-8, EN 55011:1998 Class A, UL508, and CE EN 61131-2. That was just the quick summary. There are further certifications when you get into everything that plugs into that PLC, all its expansion modules and accessories. Microcontrollers aren’t necessarily so heavily tested. They’re designed and produced by the same standards as the rest of the tech industry, which generally comes down to: it won’t interfere with radio […]

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What is a PLC?

Automated systems all need something to come back to. There needs to be some sort of brain that runs the infrastructure, does all the math, and calls the shots within the building. This needs to be a programmable device, that works on numerous inputs and outputs, to control what’s going on. It needs to be rugged, reliable, and easy to use. We call it a PLC, Programmable Logic Controller.   The Basic Problem When we fully automate a building, chemical plant, or manufacturing center, we instantly open ourselves up to hundreds of thousands of little things that need to all be overseen, adjusted, and managed in a rational way. We don’t want a person to be opening or closing a vent by hand, or to have workers walking out to manage mixing valves, or anything else by hand. Everywhere a person might do something, we need a computer, sensors, and actual controls to drive. We could use a standard desktop computer, that has the raw processing power to handle a couple million inputs and outputs, but it sucks up a ton of power, it doesn’t have that many physical IO connections, it can’t survive being dropped or beaten around, it’s too big, and it’s not guaranteed to be easy to configure. In fact, it’s probably guaranteed to be a nightmare to configure at install and every repair session. The final nail in the coffin comes in terms of security. Common […]

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