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NDES moves with motion control

DN Staff

April 17, 2000

4 Min Read
NDES moves with motion control

Chicago-This year's National Design Engineering Show (NDES) demonstrated the pace of change in motion control is fast and getting faster.

Intelligent Motion Systems Inc. (Marlborough, CT) introduced its MicroLYNX motion control system solution in a compact, easy-to-install panel mounted assembly, according to IMS marketing manager Susanna Dalponte. MicroLYNX integrates a bipolar stepper motor microstepping drive and a versatile programmable indexer with expandable I/O and multiple communication ports all running off a single supply. Available in two power ranges with the MicroLYNX4 running at +12 to +48V dc with 3A rms (4A peak) output, and the MicroLYNX7 running at +24 to +75V dc with 5A rms (7A peak) output.

Dalponte says that the MicroLYNX allows users to customize the I/O to suit the application. Six isolated +5 to +24V dc short circuit protected, general purpose programmable I/O lines are standard, with optional expansion modules that can be added for a total of 24 lines. Other I/O types available include high-speed differential I/O and analog/joystick inputs.

Animatics (Santa Clara, CA), the creator of the SmartMotor(TM), took its highly integrated and miniaturized motion control technology out of the motor and into a freestanding controller-amplifier called the RTC-3000. Measuring only 3.68 X 1.815 X 0.35 inches, the RTC-3000 is about the size of a credit card and will operate virtually any small brushed or brushless dc servo. Apply 24V dc to the RTC3000 and download a program using the host utility and you have a stand-alone system including controller, amplifier, logic power supplies, and program interpreter with 32k of program memory and 32k of data storage. Alternatively, talk interactively between the RTC3000 and a host or PLC over RS-232 or RS-485. It will also multi-task between internal program and host commands.

GE Fanuc Automation's (Charlottes-ville, VA) latest additions to its motion control product line, three new SL series brushless servomotors, are rated at 2.5, 3.5, and 5 kW output power and achieve continuous torque up to 140 inch-lb. Standard features include metric motor mounting, shaft oil seals, and MS connectors for wiring. These new larger models are also available with optional 24V dc holding brakes. Each motor rating is paired with a matching amplifier model rated for 230V ac, three-phase input power. The models are an extension of the SL V-series of servomotors and are supported by existing SLconfig set-up software.

MicroMo (Clearwater, FL) unveiled brushless versions of its IE series compact-magnetic encoder that achieves up to 512 cpr. These low-cost encoders use a wheel or reluctor with magnetic domains on the edge surface. As the wheel rotates with the motor shaft, Hall elements pick up the change in magnetic flux density as each domain passes. After electronics process and condition the encoder signals, the resulting position feedback is transmitted to the controller. The design challenges were two-fold, according to MicroMo's VP of Advanced Research and Planning Stephen O'Neil. "The first was understanding how magnetics work in encoder-based systems, and the second was the custom ASIC development.

"Overcoming the limited number of magnetic domains that can be packed on a wheel was key to the project's success," says O'Neil. "And a single custom ASIC offers engineers the choice of 16, 64, 128, 256, or 512 counts per revolution." These dual-channel encoders with digital outputs are available as integral parts of the 15-, 22-, and 23-mm rare-earth motor series. No assembly, soldering, cable making, or termination additions are required.

Oriental Motor U.S.A Corp. (Torrance, CA) showed its Alpha Step, a two-phase, hybrid, geared step motor and driver package that corrects the motor-shaft position to eliminate missed steps. According to Oriental Motor's Marketing Manager Phillip Santarelli, a motor shaft sensor, built into the motor, constantly monitors shaft position and provides the driver with feedback. Under normal conditions the driver runs in open-loop mode. When a position deviation of 1.8 degrees or greater occurs, a switch to closed loop control maintains synchronicity.

"Alpha Step's high frequency response electronically compensates for mechanical play in high-compliance systems such as belt and pulley drives," says Santarelli. "Without any gain tuning required, the driver is easier to use than traditional servo systems." Santarelli claims that there is no hunting or "jitter" that servomotors sometimes exhibit when trying to hold a position. Up to 10,000 steps per revolution of Microstep control provides smooth, low-speed operation. Integrating the feedback device into the motor also reduces motor space requirements and helps protect the device from shock loads and temperature extremes.

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