What is open loop and close loop?

Answer Posted / carl_ellis

An open loop has no feedback, like a timed operation. For
instance, an irrigation system operates for 45 minutes per
day, starting at 10:15 AM. It does this whether the water
is needed or not, because the controller, the timer, has no
feedback about the need for water.

A closed loop uses feedback. In the irrigation example, a
soil moisture sensor provides feedback to a controller to
let the controller make a decision as to whether irrigation
is needed and for how long.

Carl Ellis
Measure First



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