What is a control loop?
A system that measures conditions, applies control, and evaluates the result to maintain desired behavior.
What is a manual feedback control loop?
A loop where a human observes the system and makes adjustments.
What is an automatic feedback control loop?
A loop where a controller automatically adjusts the system based on sensor input.
What does a controller do in a feedback loop?
It compares measurements with logic and sends commands to the controlled device.
What is control loop response?
The reaction of the system output to a change in input.
What is digital (discrete) control?
Control with fixed states, usually ON/OFF (1/0).
What is analog (continuous) control?
Control with a range of values, often 0–100% or 0–10V.
Which controllers are digital?
Two-position and floating controllers.
Which controllers are analog?
Floating, P, PI, PID controllers.
Floating, P, PI, PID controllers.
The desired target value of a system.
What is a control point?
The actual measured value of the system.
What is offset (error)?
The difference between set-point and control point.
What is stability in a control system?
When the system no longer changes and remains balanced.
Can a system be stable with an offset?
Yes — stability can exist even with acceptable error.
What is two-position control?
Control with only ON or OFF states.
What is differential in two-position control?
A range that prevents rapid ON/OFF switching.
What is floating control?
Control that increases or decreases output gradually depending on error.
What type of devices use floating control?
Tri-state or analog devices.
Why use floating control?
To avoid abrupt changes and allow smooth adjustments.
What does proportional control do?
Output is proportional to the current error.
What time aspect does P control represent?
The present.
What does integral control add?
It accumulates past errors to eliminate offset.
What time aspect does I control represent?
The past.
Benefit of PI control
Reduces or removes steady-state error.
