CONTROL MGT. A $300 million machining-and-assembly addition to Chrysler's engine plant in Kenosha, WI, is busily churning out 200-hp, 2.7-litre V-6 engines for the next generation of Cab-Forward cars to be introduced this fall. The performance and response of this engine is eclipsed only by that of the facility that produces them. Once Chrysler releases an engine design, the plant's distributed automation helps integrators speed the engine to production in about 27 months, a far cry from the three or four years typical for U.S. automakers. The new addition can produce up to 400,000 engines per year.
"In terms of technology, the new plant stands out in three important ways," says Mark Fleszar,
supervisor of controls and plant facilities for advanced engine manufacturing at Chrysler. "First, Kenosha features the most extensively distributed and networked automation system ever applied to automobile manufacturing. Every processing station and every major function gets its own Telemecanique PLC. This plant marks the first major application of this brand of PLC in the U.S.
"More than 1,400 PLCs, along with 1,400 human-machine interface [HMI] panels and scores of interlinked networks, serve the plant's block, head, crankshaft, camshaft, and rod-machining lines, as well as the engine assembly lines. There are no central PLCs performing supervisory control."
Second, the plant boasts the first kit-built lines for engine-block and engine-head machining. Upon arrival from Europe, the stations were placed, connected to the transfer bar, aligned, piped, wired, energized, networked, cycled, and then integrated with adjacent stations. Often, the time it took from power-on to automatic operation was as short as two days. "Previous machines have taken up to three weeks to power-up. With the kit-built stations, startup was ongoing.
"Every station has its own distributed control and HMI. As such, our supplier was able to prototype, build, test, and start up each as a standalone unit," he continues. "Station controls are small enough for Chrysler people to tackle-perhaps 40 I/O points and a couple of [motion] axes. Compare that to the thousands of I/O points and hundreds of axes found in centralized control systems. Our distributed control and power supplies cost a bit more than the remote power supplies, I/O, and racks required by a centralized control system, but we enjoy tremendous flexibility, quicker installations, and less required training."
AMERICAN KEIRETSU. The third important technological feature is the complete application of automation and control standards throughout the plant. By forging an American-style Keiretsu, Chrysler and Square D Co. (Palatine, IL) were able to jointly develop, standardize, specify, and impose on some 80 machine OEMs a set of common control and design standards. Pleased with the success of the 2.7-litre engine program, Chrysler has also selected Square D as its partner for a new 4.7-litre engine plant in Detroit.
Before building stations, OEMs received PC disks detailing hardware and software standards, hardware configuration and integration rules, and programs for most functions, fault modes, documentation, network addressing, HMI displays, PLC memory mapping, and more. Over time, Chrysler personnel couldn't help but memorize the common station PLC addresses and I/O, which helped them later during startup. CAD templates for system components were also developed for OEMs to drop into drawings.
"Equipment must follow IEC standards, minimizing cost and size," says Fleszar. "We chose IEC equipment and cost-effective 24-Vdc I/O to help Kenosha compete with any other engine plant anywhere in the world."
Companies of Groupe Schneider SA (Paris, France) largely manufactured the plant's electrical/electronic equipment. Schneider Automation Inc. (North Andover, MA) supplied Telemecanique and Modicon automation products; Schneider Electric SA supplied Telemecanique and Merlin Gerin general industrial controls (GICs); and Square D supplied the electrical equipment.
WORLD-STANDARD NETWORKS. Distributed PLCs and HMIs at Kenosha communicate via FIPway networks and UNI-Teleway buses. The tree-structured architecture of FIPway accommodates any number of 32-node segments. FIPway links are also transparent-no PLC programming is required for implementation.
Moreover, FIPway is integral to the Telemecanique TSX 47-40 PLCs, obviating the need for extra cards. Any equipment supplied without networking capabilities is integrated simply by using low-cost FIPway links.
FIPway made installing a factory information system easier, as hardware and drivers were already in place. Too often, controls shoulder the blame for sluggish production, says Fleszar, when slowdowns really happen because stations are starved or blocked.
Nearly every station in the plant has a 6-by-10-in. Telemecanique CCX HMI; these interfaces typically replace pushbuttons and pilot-lights. Stations and machines requiring more HMI horsepower use the PC-based Modicon FactoryMate Plus.
All OEMs developed their programs using Telemecanique XTEL, which relies on a common database and tags. This suite supports ladder-logic, motion-control, and sequential-function chart (SFC) programming, as well as HMI preparation. Because XTEL is universally applied, it supports all field debugging and modifications while allowing Chrysler technicians to access any node from any other node. Such ready access is vital in a plant with almost 3,000 PLCs and HMIs.
"The crankshaft-machining department, for example, has seven FIPway layers connecting machines from 16 different OEMs," says Fleszar. "A technician anywhere in the plant can access any PLC or HMI on any of those seven networks simply by pointing and clicking."
The software also lets the technician display multiple PLCs simultaneously. Distributed control requires this because program interlocks often reference PLC addresses elsewhere on the network. "When debugging, a technician can open up to 16 PLCs at a time," says Fleszar. "Telemecanique's programming packages were the only ones offering this when the plant was designed back in 1995."
CONCENTRATED CONTROLS. "In an ordinary engine plant, power supplies and machine controls reside in large cabinets installed off-line-often on balconies-with air conditioners cooling the drives," Fleszar says. These cabinets require extensive piping and wiring, consume valuable floor space, and often require two sets of hands to troubleshoot. In addition, balconies are expensive-about $28 per sq. ft.
The new plant has just two balconies and few off-line cabinets. Instead, a single enclosure attaches directly to each station's base. It houses the PLC, I/O, HMI, GICs, motion controllers, power supplies, drives, and motor starters. In some cases, Telemecanique TXB sealed I/O mount directly to the machines.
Enclosure layout is uniform: GICs, drives, and motor equipment on the left, automation on the right. This configuration speeds troubleshooting and reduces space requirements by 35% to 45%. The OEM vendors that built these stations prewired power, control, and communications to minimize field hookups.
The power distribution system mirrors the control scheme's modularity. Square D's I-Line secondary-power busway carries 480 Vac directly above each machine. A breaker mounted on the machine's utility skid protects the busway. A fusible-switch tap plugs into the busway, while cables snaked through flexible conduit carry power to the station.
"The plant looks extremely clean and open-almost unfinished-because balconies and off-line cabinets are mostly gone and little conduit is evident," Fleszar says. "Operators can see one another across departments; access to stations for maintenance is less restricted; guarding and mist-control systems are compact; and gantry part-transfer equipment is less cluttered and more visible.
"Engine manufacturing lines tend to last for decades, and are retooled from time to time," Fleszar continues. "Because the new plant's stations and controls are modular and piping and wiring are minimized, we expect to upgrade on a piecemeal basis without seriously disrupting production. Line shutdown will be short because an entire modular station can be disconnected, slid out, replaced, and reconnected in just a few shifts."
Fleszar believes that Chrysler's future success hinges on quickly building plants that are highly productive and adaptable. As modular, kit-built machines and powerful distributed controls prove themselves, Chrysler is revving up to expand high-performance production into new areas. MA