Electronic Design

Motor Control

Small Servo Drives Use SAP To Communicate With PLCs And OITs
The PC830 servo drives offer in-creased connectivity to communicate with devices used in factory automation projects. These drives communicate with industry-leading PLCs and operator interface terminals (OITs) using a simple ASCII protocol (SAP).

Members of this drive series work with many PLCs, including Allen-Bradley SLC500, GE, Omron, and PLCDirect. The drives include I2t motor thermal protection firmware. This function protects the device against excessive or continuous current. It offers smooth low-speed performance and position accuracy as low as five arc-min. Enabling faster drive setup and tuning, this drive has a high-velocity loop bandwidth and 400-Hz operation.

Three power levels are available, including 1.1 kW continuous and 2.25 kW peak, 1.5 kW continuous and 4.5 kW peak, and 3.0 kW continuous and 9.0 kW peak output power. The series is compliant with UL, cUL, IEC, and CE regulations as well as the CE low-voltage directive. Contact the company for pricing and availability information.

Pacific Scientific, 4301 Kishwaukee St., P.O. Box 106, Rockford, IL 61105-0106; (815) 226-3100; fax (815) 226-3080; www.pacsi.com.

Linear Current-Sensing IC Offers Built-In Overcurrent Shutdown
The IR2172 linear current-sensing IC eliminates external current-sensing protection circuits. Rated at 600 V, the device offers built-in overcurrent shutdown for motor drive applications. It is compatible with 230-V three-phase ac inverter or brushless dc industrial motor drives used in conveyer belts and similar applications.

This IC has a 1.5-µm overcurrent shutdown feature with a wired-OR direct connection to the microprocessor or DSP. It eliminates slow opto- and Hall effect couplers. The direct connection between the IC and the microprocessor or DSP simplifies overcurrent protection circuits. Using a PWM output, the device runs off a bootstrap supply to reduce size requirements, parts count, and system cost.

This model is available in industry-standard SO-8 and 8-pin DIP packages. In 10,000-unit quantities, the IR2172 costs $3.55 each.

International Rectifier, 233 Kansas St., El Segundo, CA 90245; (310) 252-7105; www.irf.com.

Linear Motor Stage Offers Solution For High-Accuracy Alignment
The ALS130 motor stage employs a center-driven, noncogging linear motor as the driving element. This direct-drive device eliminates the backlash and windup normally associated with a lead-screw or ball-screw drive. This stage suits high-accuracy alignment and inspection stations.

This motor stage provides a resolution of 20 nm when coupled with an MXH series multiplier box. With a compact two-piece design, this device enhances geometrical tolerances. Straightness and flatness of the standard stage are less than ±2 µm over the entire travel. This is improved to ±1 µm with optional HAL calibration. The stage is available for precision cross-roller or linear motion guide bearing systems. The top speed of the ALS130 is rated at 500 mm/s. Also, it features a peak unloaded acceleration of 1 g.

Optional features include high-accuracy calibration at work height and precision orthogonality alignment to 5 arc-s. Contact the company for pricing and availability information.

Aerotech Inc., 101 Zeta Dr., Pittsburg, PA 15238-2897; (412) 963-7470; fax (412) 963-7459; www.aerotechinc.com.

Servo Actuator Combines Amplifier, Driver, And Controller In One Unit
The AR servo actuator offers a self-contained electronic gear that enables positioning data to be set without considering the machine's reduction gear ratio. This device integrates a servo amplifier, a servo driver, and a controller in a single unit.

Both absolute and incremental encoders are supported by the amplifier. A built-in brake control function is synchronized with the actuator's on/off functions. Four types of actuators are offered with capacities ranging from 0.4 to 2.5 kW. Also, seven different types of gear ratios are offered. For pricing and availability information, contact the company.

Harmonic Drive Technologies, 247 Lynnfield St., Peabody, MA 01960-4905; (978) 532-1800; fax (978) 532-9406; www.harmonic-drive.com.

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