While stepper motors and controllers work together to form a single system, they are separate components. The stepper controller, or stepper drive, is the "smart" component. It is programmed to coordinate the linear movements of the motor shaft. The stepper motor performs the actual work, however. Independent of each other, neither is able to perform a useful function, but together the two components form a very technologically advanced bit of machinery.
The difference between stepper motors and controllers lies in the basic function and purpose of each. The stepper motor is designed for precision movements and performs the physical work of the system. Unlike direct current (DC) powered motors, which use brushes, the stepper motor uses windings that generate an electromagnetic field when energized. The stepper controller is a programmable circuit that delivers power to the windings of the stepper motor at certain times. This controlled delivery of electrical energy powers the windings and causes the motor's shaft to rotate in the proper direction.
The stepper controller can be pre-programmed with information needed to perform a repeated precise function. The real advantage of the system, however, is the ability for on-the-fly programming. An operator can adjust the programing of the stepper controller using a computer. These alterations change the direction or speed of movement in the stepper motor's shaft.
Stepper motors and controllers are used together to create precisely measured movements in a variety of mechanical applications. This has allowed the stepper motor and controller set-up to replace expensive servo units in many applications. Modeling enthusiasts use stepper motors and controllers to create remote-controlled model vehicles that can perform a wide range of movements. Robotics engineers can use these components to create robots that can work around obstacles, climb stairs or perform tasks that are deemed to dangerous for human workers. Stepper motors and controllers are even found in the office and home environment as components of printers and computer scanners.
When used in an industrial application, stepper motors and controllers are often designed for a specific task. The precise movements of manufacturing robotics and equipment are made possible with single phase or dual phase step windings in the stepper motor. The stepper controller is either pre-programmed or manually programmed by the operator to control the movements of the stepper motor's shaft. This kind of technology is used to create machines to operate welders or laser cutting equipment that can be too dangerous for human workers.