PID_ct.sq
PID controllers, or proportional-integral-derivative controllers, are
probably the most popular kind of linear single-input single-output
controllers. This is justified by their simplicity and their effectiveness
for a large class of systems. Taking as input the difference between the
desired set-point and the measured system output ("error"
Weights can be specified either separately for the three terms, or as
a global gain
The transfer function of the controller
Translating the conceptual simplicity of the PID into an effective design
is not always straightforward. PID_ct.sq displays the graphics where common
specifications can be checked; you can manipulate the PID parameters, the
controller gain (
The figures are the same as those defined for RST_ct.sq, except for the Open-Loop Zeros and Poles and the Closed-Loop Poles which are not defined.
The System, Sample Time, method for converting to digital controller, and Damping Specification have the same effect as the corresponding menu entries defined in RST_ct.sq. Two new entries are defined.
The three parameters of the PID (
When the input of the PID controller is the error between the set-point and the measured output, discontinuities of the set-point are derived by the derivator component of the PID and yield infinite values for the control signal. To avoid that, the set-point is usually not derived. The control signal is
When No Derivator On Reference is checked, the set-point is not derived.