This lecture introduces Ziegernichels tuning, a method for choosing PID coefficients. The first method is for stable systems, where we extract delay and time constant from the step response to determine the PID constants. The second method is for unstable systems that can be stabilized with a proportional controller, where we find the critical gain and frequency of oscillation to choose the PID gains. Ziegernichels tuning provides a simple initial tuning process, focusing on the early part of the step response to quickly tune systems, although it can be aggressive and may require detuning for better control.