Smart motor integrates all controls

-- EDN, 12/7/2000

A brushless-dc servo motor from Animatics Corp integrates a controller, an amplifier, and an encoder (Picture). At $499 each, the SM2315 competes head-on with many stepper-motor systems. At the heart of the SM2315 is Animatics' motion-control chip, a µC that handles all processing functions of the motor, including the PID loop, the trajectory generator, the user-program execution, I/O control, and communications over as many as three high-speed serial channels simultaneously. The SM2315 uses a machine-wound stator and a molded, high-energy magnet encased in a die-cast aluminum housing assembly. You can program the motor for stand-alone operation or to operate as part of an RS-232 or RS-485 network. The motor can deliver as much as 32 oz-in. of continuous torque and operate at speeds to 10,000 rpm. You can use the 7 bits of accessible I/O as dedicated inputs, programmable inputs, outputs, or even 10-bit analog inputs.

A family of adapters dedicate different I/O lines as 24V isolated I/O. The adapters occupy half of the mating connector's back shell; a small screw terminal also inside the back shell provides for fast and easy connection. The SM2315 has an expansion slot for adding custom electronic functions. This slot occupies a space in the back of the motor next to the connection bus. Animatics offers expansion cards, for example, to regulate and control power to an optional external brake. The motor is 2.3 in. long and 2.25 in. wide and conforms to NEMA-23 stepper-motor frame and shaft-dimension standards. It also accepts stepper-motor step and direction signals; thus, it can directly replace both a stepper motor and its driver.

Animatics Corp, www.smartmotor.com.

—by Bill Travis