Servo line extends power range

With its PMA1 series brushless servomotors, Pacific Scientific extends the power range of its PMA series motors even wider. The new series adds three motors to one of five PMA family frame sizes. "Now we can go into even more applications where space is a premium," says Product Manager Don Neumann. The compact PMA1 series measures 55-mm sq, with a standard frame length of 125 to 175 mm, or 150 to 200 mm with integral brake. Offering a 240V ac input, the series achieves a continuous torque range of 0.21 to 0.60 Nm. "With tailored windings that match our new PC832 motor drive," says Neumann, "our motors are designed to give more torque while offering higher performance and efficiency."

Speed controls pack in the power

The AXH series brushless dc motor and board-level driver may be smaller than the HBL-type speed controls it's replacing, but it's more powerful. "When you can decrease size and increase power," says John Wong, senior engineer, "it really means something to engineers who want to downsize." With motor volume 55% less than comparable ac induction motors, and driver volume 60% less than equivalent power drivers, the AXH series achieves higher power density. Other benefits: an increased speed range from 15:1 to 25:1, and improved speed regulation from 3% to 1%. The 30W motor (2.35-inch sq) achieves a constant torque of 16.9 inch-oz, while the 50W motor (3.15 inch-sq) provides 28.3 inch-oz. Pre-assembled gearheads boost the maximum continuous torque to 53.1 inch-lbs and 141.6 inch-lbs respectively.

Commutating encoder

With six channels, the RCM1 rotary optical encoder eliminates Hall-Effect sensors inside of motors. The 2.1-inch diameter encoder simplifies assembly and eliminates Hall sensor alignment, increasing reliability and reducing costs, according to Edward Burk, technical sales manager. Combining the three-phase brushless commutation pulses, the two data channels (in Quadrature), and the reference (once per revolution) index pulse, the encoder achieves up to 2,000-line resolution, and commutates 4-, 6-, 8-, or 12-pole motors. A built-in servo groove provides plus or minus 20 degrees mechanical rotation for aligning the encoder commutation tracks with the motor rotor poles; and a patented slide-lock mechanism that aligns, centers, and gaps the encoder makes installation easy, says Burk. Another benefit: more power in the same space. Burk explains, "without the Hall board, you can increase the stack length without increasing the overall size of the motor.

Integrated servo control for the masses

SM2315 is a true brushless dc servomotor with built-in controller, amplifier, and encoder. It does nearly everything its predecessors do, for 1/3 of the original SmartMotor cost, according to Animatics President Robert Bigler. "That's $499 for quantity one," he says, "and less than $400 in quantity." A machine-wound stator and molded magnet rotor allow economical volume manufacturing, as does the die-cast aluminum housing assembly with the electronics mounted on top of the motor instead of on the back. Instead of a more expensive DSP, a dedicated microprocessor helps reduce costs and handles all processing functions, including PID, trajectory, program execution, I/O, and communications. Delivering up to 30 inch-oz of continuous torque and driving as fast as 10,000 rpm, it includes a sub network for linking peripherals such as LCD displays, OPTO-22 I/O, and digital joysticks. "Its low cost allows it to compete with steppers," explains Bigler, "so engineers can increase throughput and get closed-loop reliability."

Look ahead in time

The Advantage 800 series CNC controller combines a Turbo PMAC that handles motion and I/O, with an industrial computer embedded in a TFT flat-screen monitor. The fully integrated CNC controller communicates via USB or a fiber-optic interface (MACRO). "USB significantly reduces wiring complexity," explains Scott Gee, CNC product manager. "All you have is a 110V plug for the monitor, a USB cable, and two wires for the e-stop." A "CNC Auto Pilot" simplifies programming, and advanced "Segmented Dynamic Block Lookahead" looks out in time, determines if acceleration, deceleration, or velocity parameters are in danger of violation, then alters profiles to prevent it. "Most controllers use a static number of memory blocks for look ahead," explains Gee. "In contrast, our look ahead allocates memory dynamically, so it can expand and contract as needed. This lets us alter motion profiles in time, up to 30 sec before an impending parameter violation happens."

Virtual sensors improve

The IndexBlok(TM)family of servodrives uses SensorlesServo(TM)control to eliminate the need for a motor sensor. Instead of a feedback device, clever software resolves the rotating motor's back EMF, even down to 0 rpm, into high-resolution position feedback (i.e. 262,144 counts/rev with 8-pole servomotor). A standard PID servo algorithm acts on this position information to control torque, regulate speed, and control position. Version 2.0 uses new firmware supporting complex motion profiles and new software for easy set-up and configuration that enhances complex profiling, improves position tracking, and provides faster response to inputs. Target applications include index feeding, material handling, mechanical indexer replacement, and clutch-brake replacement. IndexBlok is now available in two module sizes: series 1000 covering 1 to 5 hp at 110/240V ac and 380/480V ac line inputs; and the series 2000, which is offered at 7.5 to 20 hp at 240V ac and 460V ac.