How to programming the Rockwell Automation PowerFlex 40 AC drive A beginner's guide Programming the PowerFlex 40 AC drive is a task commonly encountered in industrial automation and control systems. The PowerFlex 40 is a compact and versatile variable frequency drive (VFD) manufactured by Allen-Bradley, designed to control the speed and torque of three-phase AC motors. It offers a range of features and parameters that can be configured to meet specific application requirements.