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Electromechanical and Drives Division, North America: Home > Literature > Catalog
Product Review: Controller Provides Ethernet Connectivity
Multiaxis motion control for servo or stepper motors is rapidly embracing commercial technology.
By Dan Hebert, PE, Technical Editor
Multiaxis motion control for servo or stepper motors is rapidly embracing commercial technology, just like other segments of the machine control environment. Not very long ago, most motion controllers were either integral to a control bus such as VME or STD, or standalone with limited RS-232 communications. And since RS-232 communications are point-to-point, slow, and restricted to 50 feet, the application possibilities were limited.
Users of Compumotor's 6K motion controller provide some evidence that things are looking up. The company, a division of Parker Automation, makes a standalone 2-8 axis controller with Ethernet connectivity, servo or stepper operation, expandable I/O, multitasking, and enhanced position-following. The controller is supplied with Motion Planner software, a Windows-based graphical programming environment.
Ethernet offers 10MB communication rates at long distances with no point-to-point restrictions. It also lets users connect the 6K controller to a wide range of other control components. "The 6K provides seamless control and communications to other components in our products such as drives, I/O, and CTC touchscreens," says Brian Stork, the president of Stork Fabricators, Washington, Mo. Stork manufactures automatic shrink packaging equipment and uses the 6K controller in a high-speed machine where a servo axis simulates a quick-return cam mechanism.
Compumotor aims to take some of the mystery out of motion control by using familiar platforms such as Ethernet and Windows for connectivity and programming. They made the controller standalone to eliminate reliance on any existing control bus, to simplify installation, and to reduce cabling requirements.
The Ethernet connectivity is also used by Applied Materials of Santa Clara, Calif., in their metal deposition tools for semiconductor manufacture. They use the 6K controller to drive two robots, each with a total of four axes, used for wafer handling inside the tools. "The most useful feature of the controller is the Ethernet interface," says Dan Marohl, engineering manager at Applied Materials. "This interface allows easy integration between the controller and our existing controls." Lindsey Caton is an engineer with Boeing Co., Seattle. "The TCP/IP interface was a big bonus for us, " says Caton. "We employed this protocol through the Ethernet port to connect to other computer systems." Boeing uses the 6K to control a motorized automated system that compares, calibrates, and certifies non-contact sensors used for inspection and single-axis measurement.
Up to 200 I/O points via eight-point DIN rail-mounted modules can be purchased as needed. This feature can simplify the control system by eliminating a PLC. "We were able to latch in encoder counts triggered by an external sensor," says Marohl. "The 6K had the high-speed inputs to allow us to do this."
Multitasking allows the 6K controller to perform multiple independent control sequences on the same process. Resources such as I/O, memory, and serial ports can be shared between tasks. Multitasking also allows users to partition one controller into two separate controllers for added flexibility.
Enhanced position following is provided to help with applications such as packaging, bottle filling, web processing, continuous cut-to-length, and flying-knife actions.
Motion Planner software runs on the Windows platform and uses object-oriented wizards to simplify controller setup, download, and startup. "The programming software is very user-friendly, especially for people who are not motion control experts," states Ken Good, president of Shorewood Engineering, Minnetonka, Minn. Shorewood uses the 6K to control the label-dispenser/applicator head motor on their line of pressure-sensitive labeling equipment.
The software was designed for easy use, but Stork would like to see additional features in the next enhancement. "The software could be improved by adding ladder logic programming for the I/O, pre-compiled canned cam programs, improved I/O commands, variable tags, and automatic debugging for syntax and command problems, " he states.
Some simplified hardware is foreseen as well. "We would like to see a single-axis controller added to the 6K line," says Good. "We have many single-axis applications and would like a lower-cost option."
"It seems that connectors on the chassis could be combined to reduce the amount of connections between the driver and the controller," says Marohl. "We would like to see better cabling options, too," seconds Caton.
Users appreciate the support offered by Compumotor and its distributors. "Our main reason for selecting the 6K controller was great technical support and service, especially from our local vendor," says Good. Marohl agrees. "We were impressed by Compumotor's level of involvement during the development effort," he says.
© 2001 Putman Media