OneTool

PID Tuning Reference (Ziegler–Nichols)

Closed-loop Ziegler–Nichols (Ku / Tu) — not the open-loop method.

Closed-loop ultimate-gain method — starting point only

This implements the classical Ziegler–Nichols closed-loop table from ultimate gain Ku and oscillation period Tu (ultimate-sensitivity experiment). It is not the open-loop / reaction-curve (step-response) Z–N method. Gains are a manual-tuning reference, not a substitute for control design, plant modeling, or safety-aware commissioning.

Same time base as Ti / Td (e.g. seconds)

ControllerKpKiKdTiTd
P1.25————
PI1.1251.687—0.6667—
PID1.53.750.150.40.1
Ki = Kp / Ti · Kd = Kp × Td when Ti / Td are defined. P-only has no integral or derivative terms.

What is this tool?

This tool uses the classical Ziegler–Nichols closed-loop (ultimate-gain) method: find the ultimate gain Ku where the loop sustains oscillation with period Tu, then apply the standard P/PI/PID table (Kp, Ti, Td and equivalent Ki/Kd). It does not implement the open-loop / reaction-curve Z–N method. Treat outputs as a coarse starting point for careful manual tuning — not a substitute for proper control-system design, plant modeling, or safety review.

How to use it

  1. Enter Ku and Tu from a closed-loop ultimate-sensitivity experiment (safely).
  2. Read suggested P, PI, and PID starting gains from the closed-loop table.
  3. Tune on the real plant with conservative limits and monitoring.

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