Which control loop function comes after measuring the variable?

After measuring a variable in a control loop, the next function is to compare that measured variable to the setpoint, which is the desired value or target for that variable. This comparison is critical because it helps determine whether the current state of the system is acceptable or if adjustments are necessary.

By comparing the measured value to the setpoint, the control system can identify any deviation, which is essential for maintaining system stability and performance. If the measured variable matches the setpoint, the system can maintain its current operations. If there is a discrepancy, it signals that further actions, such as making adjustments based on feedback, will be needed to bring the variable back to the desired state.

Understanding this sequence—measure, compare, and then act—is fundamental to the function of control systems in instrumentation and process control. It ensures that systems operate efficiently and effectively by continuously monitoring performance against established standards.