Editor's note: Welcome to 'Integrator Update,' an occasional department examining an application from a system integrator's viewpoint.

Faced with mounting pressure to quickly move flexible, made-to-order systems, The Trane Company (Tyler, Tex.) sought help to revamp its existing coil-winding application.

At the time, people at Trane were relying on several different machines and a time-consuming changeover process to produce coils of varying shapes and sizes. Trane and The Henry Group (Greenview, Tex.) put their heads together and approached us with an exciting challenge-to design the central nervous system for a single machine capable of producing all variations of the coil product.

Fascinated by the concept, we proposed a control platform that would offer flexibility, increased quality control, less material waste, and minimal harm to the fragile coils. The solution would guarantee high production speeds, simple machine setup, and quick product changeovers.

Two of the four winders of the onboard carousel,
with a single operator at the controls.

We chose Allen-Bradley ControlLogix platform from Rockwell Automation (Milwaukee, Wis.) as the control system foundation. Unified logic, motion, and communications architecture made ControlLogix much more attractive than a fragmented approach that would involve separate logic, motion, and communications processors. Boosting its appeal was its ability to perform all of these functions through a single processor, while meeting the requirements for high speed. With The Henry Group, our manufacturing partner on the project, we set about assembling the new machine.

Trane-which subscribes to on-time, demand-based manufacturing methods-was amazed at the result. The new coil-winder is innovative and complex. The complexity is hidden from the operator by a tightly integrated control system that fully automates the production process. With the old equipment, to switch coil sizes, Trane had to shut down the line while a two-person team exchanged cumbersome parts.

Today, changeovers are as simple as scanning the bar code of the desired product and entering a build quality. A custom Microsoft Windows NT application uses bar codes to catalog and retrieve machine setup parameters for each product.

The new coil winder consists of two major sections-the inner, or 'onboard,' section and the outer, or 'offboard,' section. The inner section is a rotating carousel with four wind arms, while the outer section is a collection of four separate stations that load, glue, shape, and discharge the product.

A 6.5 x 7-ft panel houses the central
nervous system of the auto coil winder.

A slip-ring provides time-critical communication between the onboard and offboard components. Because of size limitations and the cost-per-contact of slip-rings, we had to minimize the amount of communication. To accomplish this, we opted to use ControlNet and DeviceNet. Redundant ControlNet bridges wired through the slip-ring provide communication between the Onboard ControlLogix processor and a remote chassis. A DeviceNet scanner within the remote rack relays status and control for all offboard components.

A-B servo amplifiers and motors are located on the onboard and offboard sections of the winder. To facilitate coordinated control between servo axes, communications between the onboard motion axis controllers and the offboard servo amplifiers are also wired through the slip-ring. The servo communications include quadrature encoder, discrete, and analog signals.

An A-B field-oriented control ac drive, selected for its ability to operate in torque mode with a speed offset, provides tension control for the unwind operation. We computed torque from the acceleration and speed of the winding axis and the tension set point, and calculated the diameter of the unwinding axis from the weight of the axis, transmitted by load cells.

The coil-winder helps The Trane Company meet increasing demand for made-to-order systems.

Integrator: Tegron LLC, Longview, Tex.; Steven Voelzke, president; www.tegron.com.For more information, visit www.controleng.com.