Powerful, More Affordable Digital Drives

Moore's Law has transformed digital drive technology in much the same way it has the computer industry, offering drives twice as much processing power and memory for the same prices offered 18 months to two years ago. Digital drives are using that affordable computing power to provide more elegant control algorithms, higher levels of distributed control and increased support for factory networking.

And according to Scott Evans, director of drives for Danaher Motion in North America, these intelligent drives are using distributed control and more affordable drive platforms to expand the application base of servos into less expensive machinery.

Trends in Drives

Evans says drives were historically used as torque-only or torque-and-velocity mode amplifiers with intelligence upstream in a central location because that's what available processing resources would allow. “Now with more intelligence in the drives, they are better suited to handle tasks and share among themselves in a horizontal or distributed way,” he says. New drives offer better shaft performance, faster settling times and smoother accel and decel ramps, but the average cost is generally the same and affordable for a wider range of applications.

“The drives are getting more and more intelligent, but the expense of that intelligence is not going up,” says Evans.

The result is that OEMs are deploying more precise technology in machinery that historically couldn't afford it. For example, the manufacturer of a small labeling machine that sells for $25,000 couldn't afford to put $15,000 of servos on it, which is what 2 to 3 axes of servos might have cost five years ago. Machinery OEMs are deploying servos where that was out of the question and unheard of years ago.

With even higher levels of performance in the future, Evans says this should take us to true plug-and-play and a true convergence of Ethernet technologies. So far, manufacturers have migrated from their own version of Ethernet hardware to standardizing on IEEE 802.3 just like the computer industry. “We are seeing more and more people embracing the TCP/IP transport layer, too.” Evans says. “I predict the next step will be a convergence of protocols and even greater standardization over time.”

	Digital drives are now converging on Ethernet standards to improve communications.