PID Lab - Simple Internet tools
The purpose of this web site is to introduce simple Internet tools (Java applets) for PID controller design and tuning. Using these applets, PID tuning based on known process model or experimental data can be done in a very short time. The applets may be used also for education purposes (such as in USA, France, Australia, Czech Republic, Republic of South Africa etc.).
PID controllers are used in industrial practice more than 60 years. The development went from pneumatic through analogue to digital controllers, but the control algorithm is still the same. The PID controller is a standard and proved solution for the most of industrial control applications. In spite of this fact, there is not any standard and generally accepted method for PID controller design and tuning based on known process model. Over the years, there are many formulas derived to tune the PID controller. However, there exist only a few universal procedures, which can be used for arbitrary order irrational or non-minimum phase transfer functions. One of these is described in PID controller design on Internet: www.PIDlab.com. This method allows to design the real 2DOF PID controller for practical requirements, e. g. gain and phase margins. Additionally, the method allows to specify more complicated Nyquist plot shape requirements. The method is usable for any linear system (unstable, non-minimum phase, with or without dead time). This method is useful especially for stable non-oscillatory or slightly oscillatory processes, where the Nyquist plot shape requirements are well known. The method described is implemented in PID Controller Designer and PID Control Laboratory