provided by: EDN Motion-control cards from Performance Motion Devices can drive as many as four brushless, stepper, and dc motors. The cards allow for user-selected profiles, including electronic gearing of two-axis, S-curve, trapezoidal, and other trajectories. They use the host PC only to provide power and to communicate the motion profiles through the CAN (controller-area-network) bus, PCI, PC-104/ISA, or serial port, ensuring that the motion-control system is not at risk due to the long latencies and unpredictable operation of the operating system. The card provides a feedforward PID (proportional/integral/differential) filter and dual biquadratic filters. Outputs of the cards include PWM, analog, pulse, and direction.
The cards can trace as many as four motion-parameter registers, including those for position, velocity, acceleration, and servo lag. You can stream the trace data to the host or store it on the card for later examination. The ability to trace the motion registers enables you to deduce optimum trajectories and perform servo-tuning. Further, you can use the error values in adaptive-machining applications in which a card records the motion deviation from ideal on the first manufactured part. An engineer or an adaptive program can then correct for any deviations in the control program, so that subsequent parts are more accurate, even when the tool loads change due to repeatable breakouts or other problems.
The position range of the card is 62 billion counts, and the signal-conditioned quadrature-encoder inputs reject noise. Available in both short-PCI-card and ISA PC-104 formats.
-by Paul Rako
Performance Motion Devices Inc, .
author: Edited By Fran Granville
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