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Motion Controllers
By Laurie Toupin, Contributing Editor -- Design News, January 12, 2003
Easy Configuration
National Instruments PXI-7344. This axis controller for steppers or servos first debuted in 1999, and has gained a large following since, says Motion Control Product Manager Jayson Wilkinson. New to the product is Motion Assistant, software that Wilkinson says makes it easy for even non-programmers to create motion profiles on the fly. One feature, for example, teaches the controller the best three-axis contour path through required points. Since it's PXI-based, the board can share signals with peripheral boards, totally bypassing the computer. "This gives a higher performance and saves time on integration," says Wilkinson. (www.ni.com). Enter 701
Back to Basics
Delta Tau PMAC-PC/104. Known for its high-end controllers, Delta Tau's newest offering has a list price of under $1,000. A single card can handle up to four axes, stepper or servo, in any combination. The compact (4-inch), DSP-based board is targeted at engineers who want to move from point A to point B. Additional I/O is available on a daughter board, making for a modular system that meets the needs of engineers who want to do more. Several CNC-makers are already developing machines based on the new card. (www.deltatau.com). Enter 702
Low-Cost Control
Ormec Orion. "Our goal is to make distributed network drives available at analog drive prices," says David Carr, engineer and vp of product development and marketing at Ormec. To do that, engineers split the functionality of a board-level controller between a PC and Ormec's networked ServoWire Drives using the Firewire serial bus.
Companies like Spego, which manufactures automation equipment have already taken notice of the technology: "We like the simplicity of the wiring, and it's the most cost-effective solution for us," says VP Clint Spiegel. (www.ormec.com). Enter 703
Call it the Base Model
Galil's DMX 21x2 and 21x3. This new controller is basically Galil's top-of-the-line controller (same 32-bit processor, memory, and PID), at half the price and half the size. Engineers reduced cost by eliminating some expensive features deemed not critical to functionality or that could be achieved externally, such as opto-isolated inputs, and analog inputs and outputs. The 8-axis Ethernet-based board features coordinated motion and electronic gearing. (www.galilmc.com). Enter 704
All Things to All Axes
ACS-Tech80's SPiiPlus. Unlike other controllers, which use a single DSP for all axes, this controller is built on a distributed, multiprocessor platform. There's a dedicated DSP for each pair of axes and servo control loops, interfaced with a Pentium 586 PC for communications. For applications beyond eight axes, a second DSP card with a communications link can be added. Built-in sine-cosine multiplication hardware eliminates the need for a separate interpolation box for quadrature of signals. Processor updates the servo loops at a fixed 20 kHz rate, for a positional accuracy of less than 1 nm. (www.acs-tech80.com). Enter 705
Real-Time Motion
Parker Acroloop ACR 8020. This new controller does floating-point math at the chip level, enabling it to achieve virtually real-time motion control. Using a 120 MFLOP DSP with 64-bit math and automatic roll trajectory, the controller processes calculations in just 100 to 500 µsec. That's quick enough for applications like Palomar Technologies' six-axis system for positioning optical components. Engineers needed the ability to adjust location on the fly, since the optical center of the devices do not match the geometric center. (www.acroloop.com). Enter 502
