What is the purpose of a calibration deadband in loops with noisy sensors?

• A. To prevent actuation due to minor fluctuations; require a minimum error before action
• B. To maximize responsiveness to small changes
• C. To eliminate the need for calibration
• D. To increase sensitivity to noise

Answer: (A)

A calibration deadband prevents actuation from minor sensor fluctuations. In loops fed by noisy measurements, the readings can wander around the true value even if the process isn’t actually changing. If the controller acted on every tiny deviation, the output would chatter, wear actuators, and calibration updates could become unstable. The deadband creates a tolerance window around the calibrated value so small errors within that window are ignored. Only when the error grows beyond the deadband does the loop respond, which stabilizes the system and reduces unnecessary movement. The trade-off is that very small changes aren’t corrected immediately, but that’s intentional to improve robustness against noise. The width of the deadband should be set above the typical noise level but below the level of change you want the system to correct.