Credit-Card Sized Servo Controller/Amplifier

-- Control Engineering, 1/1/2000

Santa Clara, Calif.-Essentially the size of a credit card, Animatics Corp.'s new RTC-3000 combines the functions of a servo controller and amplifier in a miniature, free-standing unit. Experience with miniaturized motion control design allows running virtually any small brushed or brushless dc (bldc) motor, according to the company. This claim includes motors with a wide range of inductances, and applies to 'difficult to drive' very low inductance motors. Motors rated up to 1 Amp continuous duty (3 A peak) at 24 V dc fit the 'small' motor designation. RTC-3000 eliminates the need for full-sized controllers often used to drive small servo motors.

After downloading a program from a host and applying 24 V dc power, RTC-3000 provides several system functions and features, such as controller, amplifier, logic power supply, and program interpreter (32K program memory/32K data storage). Multitasking between host commands and the unit's internal program is available, along with series communication (RS-232/485) to a host or PLC. Up to 120 units can operate on one RS-485 network.

RTC-3000 incorporates various system inputs; for example, for the encoder, motor, Hall sensors (in case of bldc motors), and a second encoder. General-purpose I/O points include several 10-bit analog input channels. Designed for multiaxis control, the device's small size also makes it effective to be placed at each motor. In such a configuration, the benefits are reduced system wiring plus ability to distribute control and I/O functions close to point of actuation.