Abstract
Proportional (P), proportional plus integral (PI) and proportional plus integral plus derivative (PID) controllers are designed for a time-delayed process having latency L and a single right half-plane pole at s=λ, with λL < 1. Explicit designs are derived from the concept of phase margin, and an optimum stability approach for PI controllers is based on a parameter plane study. An optimum gain margin design is also given for P control.