PID : Proportional integral derivative control can easily be understood through simple analogies.

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    Learn to Ride the Electrohydraulic PID Seesaw
    Proportional integral derivative control can easily be understood through simple analogies.…ie-pid-control-dummies-me

    Maybe it can interest people, innocents and less innocents.


    When explaining operation of complex equipment, such as an electro-hydraulic closed-loop position control, different approaches are adopted depending upon who the explanation is aimed at. Such explanations tend to fall into one of two categories — a full mathematical analysis for people with a strong control theory background, and a very simplistic instruction-manual style for everyone else.

    The explanation that follows aims to fall in between these two extremes for the benefit of those who do not have a classical control theory background but nevertheless want to understand something of the why of a control system rather than just the what. If you can grasp the basic function of each component or adjustment, you may not be able to design a system from scratch — but you should have a much better understanding of how it works, how to set it up, and what to look for when something goes wrong.


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    Even the simplest Chinese-made PID's are capable of scarily smart behaviour. Put one into 'learn mode', give it a target temperature and use it as a switching thermostat on a brand-new furnace system and within a few hours it will be capable of holding the set temperature within a degree or two. Temperature overshoot- where the thermostat switches off too late, or undershoot where it switches off too early is entirely overcome by the PID's own internal algorithms.