Dead time beats PID

When transport delay exceeds the process time constant, plain PID will disappoint.

Why it works

The controller acts on stale information and over-corrects. Reach for feedforward, a Smith predictor, or fixing the delay itself.

Do it exactly

Estimate with the rule, then check it against the calculator that models it properly.

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More in Control Systems

• Sample at least twice the fastest signalTo capture a signal faithfully, sample above 2× its highest frequency — in practice 5–10×.
• Aliases fold around half the sample rateA tone above fs/2 reappears mirrored below it — 900 Hz sampled at 1 kHz reads as 100 Hz.
• Find the edge, then back offTuning by hand: raise proportional gain until the loop just oscillates, then halve it.
• Read the oscillationSlow rolling oscillation = too much integral. Fast jitter = too much derivative amplifying noise…

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