For example, if the gain margin plot in Control System Tuner indicates a 10 dB margin at
a particular frequency, then trace the contour starting at (Gain,Phase) = (10,0) to
see how a given amount of phase variation reduces the allowable gain variation at that
frequency. For example, if the phase can vary by 30 degrees then the gain can only vary
by about 8.4 dB (red mark).Interpreting the Gain and Phase Margin Plot
The stability-margin plot for Margins Goal or TuningGoal.Margins shows in shaded
yellow the region where the target margins are not met. The plot displays the current
gain and phase margins (computed using the current values of the tunable parameters in
the control system) as a blue trace.10 Control System Tuning