A VSD is a type of adjustable-speed drive used in electro-mechanical drive systems to control AC motor speed and torque.
A PLC is an industrial computer which has been adapted for the control of manufacturing processes such as assembly lines, production lines, robotic devices or any activity that requires high reliability control and ease of programming and process fault diagnosis.
A HMI is an interface that allows humans to interact with the machine through a touch panel.
SCADA is a control system architecture comprising computers, networked data communication and graphical user interfaces for high level process supervisory management, while also comprising other devices like PLC's and PID controllers to interface with process plant or machinery.
