Motion and machine control: One platform, one program. That's what packaging professionals are saying sets Rockwell Automation's Integrated Architecture apart from its predecessors. Bringing those two worlds together helps ease programming and troubleshooting, boost equipment speed and accuracy, add flexibility, and cut costs.
On board early
One of the first packaging machinery manufacturers to see the benefits inherent to the integration of motion into Rockwell Automation's ControlLogix platform was Hartness International, Greenville, S.C. The company's equipment, including vertical loading, continuous motion, and rotary packers, is designed to package virtually any rigid container — regardless of shape, size, or material — into nearly any case or tray, plastic or corrugated. "We've been using PLCs in our equipment for many years," explains Dwight Crotty, engineering manager. "About three years ago when the ControlLogix processor was being introduced, we were in the market for new control systems for our servo machines. Rockwell was instrumental in helping us convert, providing the needed resources and training."
The heart of the system, as far as Hartness is concerned, is its integrated motion-control capabilities. Traditional motion-control servo applications use a PLC for machine control, factory interface, networking, safety circuits, and so forth. A second dedicated controller coordinates motion through programmable servo-axis and motion commands. The PLC simply tells the controller when to perform a motion, but all motion-control intricacies are handled in the servo controller. One drawback to this approach is that separate application programs must be written for each controller, each with a unique programming package and language that must be synchronized. The result is an application that is difficult to operate and maintain, and not always reliable.
"We found that most of our customers were very good at PLC logic," Crotty explains. "They had software, laptops, and could get online with the PLC and make changes. But when it came to motion control, they didn't want to get involved." Hartness had to support two programming languages and staff experts in both areas. "ControlLogix 5550 with 1395 controllers brought these two worlds together," says Crotty. "Motion and machine control are accomplished in one platform, with one program, and one laptop to hook up."
The single programming language — RSLogix 5000—also makes communication from the basic PLC through DeviceNet or Ethernet simpler than it was in previous generation products, says Crotty. The combination not only simplifies machinery, it makes troubleshooting easier as well.
One-hundred-plus years in the packaging machinery business has given Standard-Knapp, Portland, Conn., a good idea of what its customers want: Flexibility, speed, simplicity, robustness, and equipment compatibility. Rockwell Automation's system-wide approach to packaging solutions fills that bill.
Standard-Knapp manufactures tray packers, shrink wrappers, and vertical case packers for clients such as Hormel, Pillsbury, AnheuserBusch, and Miller Brewing. These companies are always looking to ramp up production speeds. There is a significant problem with traditional packaging systems that use a dedicated controller for logic and I/O control, and a second for motion control. The controllers need to be linked together using hardwiring, serial interface, or some other means of communication. Information isn't available in real time. This makes synchronizing and programming the system protracted and difficult. The amount of time it takes a data packet to travel from one processor, over the wire, to the next, and through a conversion program, affects accuracy. Motion and machine control can get far enough out of sync to impact machine performance. Because Integrated Architecture ties all control functionality into a single, multitasking controller platform, packaging machinery manufacturers achieve higher system performance, not to mention faster application development, easier maintenance, and lower overall cost.
One of Standard-Knapp's most innovative machines is the 296I Traypacker. With an integrated shrink-wrapper, it has up to six servoaxes, depending on the application. Dubbed the Continuum, it takes product that's already been bottled, capped, and labeled, and collates it into a pattern of 6, 12, or 24 containers. Once collated, the machine wraps a corrugated tray around it, glues all four corners, then wraps it in clear or printed film. The Continuum was originally designed and configured to run at 70 trays/min, but recently has been redesigned for 80, then 90, and now 100 trays/min.
Kristofer Kolstad, vice president of marketing and head of Standard-Knapp's Traypacker/Shrinkwrapper product team, says, "Before ControlLogix, communication within the machine was an impediment to higher speed. But with the new software, we are using EtherNet/IP to communicate between our input and output controllers which improves things dramatically." Beyond traditional PLC needs, the company uses the same software for motion-control needs, to group products, feed film to the wrapper, stack one tray on another, and properly position the bottom pack.
In addition to the integrated motion-control capabilities, StandardKnapp has found other benefits, as well. "Hardware costs less because there is less of it," says Kolstad. "It also offers more functionality and now that we are in one ‘kernel' so to speak, the diagnostics are simpler." Rather than having PLC software and a separate graphic-motion-language (GML) program, technicians can deal with just one program for the entire machine. That should make it easier to diagnose problems.
More control, less money
Growing from a one-man shop to packaging-machinery giant, Douglas Machine Inc., Alexandria, Minn., manufactures everything from case and tray packers, shrink-wrappers, and multiwrappers to gantry-style and robotic palletizers/depalletizers, sleevers, and multipackers. One of several applications benefiting from ControlLogix is the company's multi-wrapper machine.
Douglas manufactures three basic models, running at speeds of up to 40, 70, and 100 cycles/min, and ControlLogix with integrated motion, controls the entire operation. Basically, the machine receives loose bottles, cans, or cartons, accumulates them into the correct pack pattern, and wraps them with either clear or printed film. An Allen-Bradley Ultra servo cuts the film and delivers it to the wrapping station, where a rotating wand wraps the film around the product, overlapping the seams on the bottom. Each multi-wrap then moves to a modular shrink tunnel where the package, including the bottom, is heated. Controlled airflow and belt speed in the tunnel assures a uniform shrink to the film. The Allen-Bradley motion-control module, which runs the servo-driven film delivery assembly, is integrated into the machine-control software.
Before ControlLogix, Douglas used stand-alone motion controllers that communicated with the PLC. With the new platform, they've been able to eliminate a dedicated operator interface for the servo controller. That's now handled through the main graphical operator interface for the machine.
A single Allen-Bradley Panelview human-machine interface (HMI) can seamlessly control the integrated motion, the machine's discrete control, and the communications to the user's MES system without significant integration costs, says Rockwell Automation. This is part of the Rockwell Automation ViewAnyWare strategy — the visualization component of Integrated Architecture that delivers a unified and scalable suite of monitoring and control solutions. All ViewAnyWare products are platform-independent. This not only cuts costs significantly, but makes way for faster development time and the ability to reuse applications on different platforms, giving OEMs options to meet different end-user choices without adding development costs.
Contrast this with traditional packaging applications where motion and sequential control are split, and many end users are forced into several HMI solutions. They must maintain software licenses and expertise for either different companies or different software packages. The gap between platforms adds training costs, cuts productivity, lessens connectivity, and reduces the ability to customize.
According to Steve Swanberg, Douglas' director of electrical engineering, integrating motion into ControlLogix is typically less expensive than having a dedicated machine controller and servo-controllers. And, as the number of servo-axes increases, so do the savings. Because the motion-control module is in the ControlLogix rack, external wiring between machine controller and servo-controller is eliminated. "Only one cable is needed between the module and servo drive," he explains. Moreover, both technicians and customers only need to be familiar with one software package to support the machine. The advantage of less wiring becomes even greater when OEMs decide to use Rockwell Automation's new SERCOS optional network capabilities.
A unique application from Kisters Kayat Inc., Edgewater, Fla., comes as a new bottle-packaging machine called the 320/70 iRT WrapAroundPacker. It not only produces a full wraparound box with a partition, but also turns out display tray packages for the end of supermarket aisles and packages six 64-oz bottles and twelve 46-oz bottles in both a full box and tray. For nearly two years, the company worked with
Rockwell Automation to design and build an open, integrated controller-based packaging machine to control a robotic partition former and inserter, product-group loading section, and compression section running continuously at 70 cases/min.
The main brain controlling these five integrated functions in one machine is ControlLogix with integrated motion, a single control platform designed to ease setup and programming, cut operator training time, and build in modularity for future expansion.
Such a complex machine requires precise integration of motion and logic control to coordinate its multiple functions. For example, for motion control the machine uses seven Allen-Bradley servo motors. To ease motion coordination, a SERCOS card in the ControlLogix rack controls all Allen-Bradley 1394 servo drives and MP-Series servo motors. Absolute feedback up to 2 million counts/revolution in the servo motor tells the processor its exact location so users don't have to "home" the machine by moving the product to a sensor on start ups or recovery from power outages.
Using robotics was a first for Kisters Kayat. The company's main objective for the integrated robotic partition former and inserter was to simplify the programming and control. Line synchronization, sensors, faults, program selects, and I/O run through ControlLogix. If an end user needs a format or package change, predetermined settings in the HMI automatically transfer to the robots.
Another key aspect for end users is fast changeover at the touch of a screen. Packaging lines change frequently and downtime isn't an option. Most line changes are entered on the operator interface, including distance between pins, package size, glue temperature, and bottle size. Using an open network to transfer data to and from the HMI to ControlLogix, operators can make changes on the fly. For example, they can adjust a number on the screen to change the position of glue on a box.
The integrated motion-control platform has definitely made life easier for Kisters Kayat engineers. The single integrated system cuts operating costs, streamlines development, and eases programming. It also allows more flexibility. Kisters designs and builds modular packaging machines that ensure maximum flexibility by allowing customers to easily and efficiently change applications at any time.