Tuning flow control loops
Flow loops are the fastest and noisiest loops on a plant. Why they want low gain and fast reset, why derivative belongs at zero, and what usually goes wrong.
Tuning guides by loop type
What each class of loop wants, what usually goes wrong with it, and what to check before you change any constants.
Tuning level control loops
Level is integrating, not self-regulating. Why most level loops should be tuned loose, and why tight level control causes problems downstream.
Tuning pressure control loops
Gas pressure loops behave like slow flow loops; liquid pressure is faster still. How volume, compressibility and valve sizing shape the tuning.
Tuning pump and fan speed loops
On a VFD loop a significant part of the dynamics lives in the drive. What to check in the drive before touching the controller.
Tuning temperature control loops
Temperature loops are slow and lag-dominated, and the one common case where derivative action genuinely earns its place.
Tuning pH control loops
pH loops combine extreme process nonlinearity with long sample dead time. Why tuning is rarely the answer and what usually is.