Open-loop controller: Difference between revisions

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== Applications ==

[[File:Electric Clothes dryer.jpg|thumb|Electric clothes dryer, which is open loop controlled by running the dryer for a set time, regardless of clothes dryness.]]

An open-loop controller is often used in simple processes because of its simplicity and low cost, especially in systems where feedback is not critical. A typical example would be a domestic [[clothes dryer]], for which the length of time is entirely dependent on the judgement of the human operator, with no automatic feedback of the dryness of the clothes. Generally, to obtain a more accurate or more adaptive control, it is necessary to feed the output of the system back to the inputs of the controller. This type of system is called a [[Closed-loop transfer function|closed-loop system]].

For example, an [[irrigation sprinkler]] system, programmed to turn on at set times could be an example of an open-loop system if it does not measure [[soil]] [[moisture]] as a form of feedback. Even if rain is pouring down on the lawn, the sprinkler system would activate on schedule, wasting water.