Design and Implementation of a PID Controller for the Low-speed Wind Tunnel

The purpose of this research is to investigate the implementation of an external PID controller on an existing variable frequency motor drive (VFD) while using MODBUS communication to read/write data from a LabVIEW station. LabVIEW is the chosen user interface and programming language. It allows human-machine interfacing for the collecting, displaying of information, and automation of the system. The main objective was to develop a new controller to facilitate the operation of the wind tunnel. The current setup makes the operator set the motor frequency manually which then correlates to a test section wind velocity. This involved a calibration period and pressure measurements for its determination. The new setup takes all the manual calculations out of the operator’s hand and leaves LabVIEW in charge. The user can now demand a test section velocity and the controller makes all the necessary adjustments to automatically achieve it