A brand-new family of MACO control systems from Barber-Colman Co. in Love's Park, Ill., employs a "building-block" strategy intended to reduce the system's installed cost while improving its performance.

Called MACO DS, this modular control system literally snaps together from three types of new components: process-specific control modules, a quick-connecting distributed I/O system, and a PC-based operator interface. These components communicate via high-speed buses and industry-standard communication networks such as Ethernet and CANBus. "It's a truly open system," says automation products manager Bart Polizotto.

"The focus of this system is on lowering the total installed cost," Polizotto emphasizes. That cost is roughly 25% less than for earlier MACO systems, he estimates.

Barber-Colman previewed MACO DS at the recent K'98 show in Dusseldorf, Germany. While the system will not be fully commercial until July, a prototype was demonstrated on a rotary blow molder from Graham Engineering Corp., York, Pa.

Control modules on cards

For process control, MACO DS relies on what the company calls "Application Specific Blocks," which contain I/O card modules with on-board microprocessors and also have room for an optional central microprocessor that can run custom control routines. A "block" holds up to six of these intelligent I/O cards, each handling a specific control task. Users simply select the cards that meet their application's needs.

When MACO DS arrives this summer, Barber-Colman will offer off-the-shelf control modules for blow molding, injection, extrusion, temperature, and motion control. Some of these cards contain control features already familiar to Barber-Colman customers--for example, Impact injection molding control. Other cards will be new introductions that will provide performance increases, according to Polizotto. For instance, a high-speed card currently used only in blow-molding will be applied to injection molding. Polizotto says the 0.1-millisec scan rate of this card will permit a more detailed shot profile of 100 steps instead of the current 10.

Get rid of the 'rat's nest'

MACO DS also offers direct wiring of the system's components into one or more "terminal I/O blocks." Each block has a base comprising 25 DC, AC, and analog I/Os.

More than just a place to hook up the wires, the base also supports a snap-on communications adapter, which provides a single-point connection with the application-specific block over a high-speed bus. Polizotto says the chief benefit of the terminal-block system is simplified wiring and the ability to buy only the amount of I/O you need.

A PC for the operator

The system's new operator station, called Optima PC, features a color touchscreen and an integrated pointing device. Because it runs on Windows NT, the system offers quick integration with a variety of factory networks from Barber-Colman and other suppliers.

Optima uses Wonderware InTouch software for its operator interface. Standard features include multiple windows, on-line help, animated objects, SPC, on-line trending, and recipe management.

To upgrade earlier MACO operator stations for use in a MACO DS system, Barber-Colman offers a small Windows CE device that bolts onto the older system.