New Modbus-Enabled Closed-Loop Stepper Motor From Autonics

Recently, Autonics announced the AiC-MT series of closed-loop stepper motors that come fully equipped with Modbus TCP communications, enabling a larger network for high-precision motor control systems.

Autonics AiC-MT Series Stepper Motor

Similar to the other AiC series stepper motors, the AiC-MT is a closed-loop motion system that provides real-time feedback to the control system of the motor position. These motors, being stepper motors, provide high speed and high torque to your motion application. The AiC-MT motor uses Modbus TCP for industrial communications which provides better compatibility with a wide variety of control systems and allows up to 254 axes on one network, compared to the AiC-CL which uses CC-Link for communication.

Autonic’s new closed-loop stepper system. Image used courtesy of Autonics

The AiC-MT product line is broken up into four categories with a motor, a driver, and a combination set of motor and driver for each category. The different versions refer to how the motor is assembled. There is a standard, integrated brake, integrated gear head, and an integrated actuator. Different frame sizes are offered for each category as well for example, the integrated gear head models come in 42 or 60 mm frame size, while the integrated brake type includes sizes 42, 56, and 60 mm. Each size and type can be ordered with a motor/driver combo or individual components.

The integrated encoder provides real-time positioning information back to the controller which reduces hunting that is often found with servo motors and less likely to miss steps when using the counting method for position. The stepper motor works best at low-speed and high-torque applications.

The drive and motor are configured and tuned using the atMotion software provided by Autonics. The atMotion software allows users to tune the motion parameters of the live system and monitor the changes using the built-in data monitoring interface.

Benefits provided by stepper motors as compared to brushed DC motors. Image used courtesy of Autonics

Stepper Motor vs. AC/DC Servo Motor

When you have a motion application that requires low speed and accurate positioning you might turn to a servo motor. Industrial servo motors often require AC three-phase voltage and are quite expensive and complex to integrate. A stepper motor works similarly, only a stepper motor is a brushless motor that requires a DC voltage input of only 24 to around 60 volts.

Since stepper motors have a fixed number of steps per revolution, they can be used in an open-loop type system by simply counting the steps the motor rotates, and still be relatively accurate concerning motor position. With the AiC series, a built-in encoder can be provided which will report the position of the motor in real-time, thus making the system a closed-loop type system for even greater assurance of precision.

The system can be advanced even further by adding a brake to the motor assembly. This makes the AiC series an economical substitute for an expensive and complex servo motor and drive system.