Delay

When sensor readings are noisy, the usual fix is to add filtering.

Moving averages, first-order low-pass filters, median filters, and consecutive confirmations all make curves smoother. The display looks calmer, and alarms are triggered by fewer spikes.

In closed-loop control, filtering is not free.

While filtering suppresses noise, it also makes the controller see an older state. For display, slightly old data is often acceptable. For control, late feedback can become overcorrection.