Closed-loop control process
A closed-loop control process has a
feedback that is related to the output of the system. Take
for example a flow control system, the system has as input a desired value,
also known as setpoint, and this setpoint is received by a controller that acts
on the process sending a control signal to a flow valve. So
far we have described an open control loop where there is no feedback.
To close the loop, it is required a sensor
that measures the flow that varies according to the position of the valve, in
this way the flow sensor measurement represents the feedback of the system.
The system then calculates the error or
difference between the flow set point (reference value) and the feedback value, also called
process value, which is processed by the controller to again act on the valve
which will simultaneously produce a variant of the flow. At
the end the goal is that the difference or error between the reference and
feedback is closest to zero.
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| Closed-Loop Control Process |
