News and New Products

Servoamp drive is small, versatile, powerful, and networked

By Bill Schweber -- EDN, 1/6/2005

The all-digital Accelnet Micro servoamplifier from Copley Controls squeezes the physical envelope and expands the performance envelope. The single-axis, 2.5×1.6-in., pc-board-mountable design can be part of the overall control, power-supply, or interface board. It includes low-cost, CANopen networking for multiaxis control, as well as system-level functions. Applications include portable instruments, medical instrumentation, lab equipment, and even vending machines. The unit’s size lets you put it near the motor for simplified wiring and reduced RFI output, which long cable runs can aggravate (Picture).

Output ranges are 20 to 55V at 3A continuous and 6A peak or 20 to 90V at 2A continuous and 4A peak. It accepts ±10V analog-control and digital-PWM signals. Further, depending on operating mode, it lets engineers replace stepper motors with faster, higher power brushless servomotors, because it accepts and translates stepper-control signals. For enhanced performance, it applies field-oriented control algorithms.

Using the built-in software, you can create, via Java scripts, a sequence of automatic motions as a series of commands with special velocity, position, and acceleration profiles for each, and then store these scripts in the amplifier’s flash memory for autonomous operation. You can also instruct the system to change basic parameters, such as amplifier gain, to match sudden changes in load or situation. The servo loop is reasonably fast, with 2.5-kHz current-loop bandwidth, 14-kHz current-loop update rate, and 3.5-kHz position- and velocity-loop update rate. Prices for the Accelnet Micro networking servoamp begin at $298 (one to nine).

Copley Controls Corp, 1-781-828-8090, www.copleycontrols.com.