Beyond the Third Dimension
It's hard to imagine anyone using the old drafting table and instruments to design anything today, but Tegron LLC used to employ labor-intensive techniques to create and revise drawings to automate customers' industrial processes. Under the old approach, recalls Tegron design leader Wayne Gatlin, each drawing required multiple checks by various people.
It's hard to imagine anyone using the old drafting table and instruments to design anything today, but Tegron LLC used to employ labor-intensive techniques to create and revise drawings to automate customers' industrial processes.
Under the old approach, recalls Tegron design leader Wayne Gatlin, each drawing required multiple checks by various people. Although cumbersome, the manual method worked until a baggage-handling project, with a very tight deadline, was undertaken. "It wasn't a hugely complex project for motion control and such. It just required a lot of drawings—literally thousands of drawings," he says.
Thanks to automation design software, Tegron and its customer had a successful result. Gatlin reports time to generate a drawing was cut from hours to minutes, or less. And the software cut the drawing error rate by 90%, increasing throughput by 50%.
Now new software improves traditional, computer aided design (CAD) by automating tasks and incorporating mechanical- and electrical-models of real world objects. Other advances in automation design software promise to resolve the problem of translating from one programmable logic controller (PLC) language to another, and a final software class eases construction of human machine (HMI) and other systems' interfaces.
For the baggage-handling project, Tegron used AutoCAD Electrical from Autodesk, Inc. Gatlin says that Tegron had been looking for a way to automate routine tasks, such as control wiring for motor starters. Before adopting AutoCAD, it had considered other approaches, including a custom-built system.
Tegron has built a number of small tools to customize the software, and Gaitlin notes that he'd like to see some improvements in the back-end database implementation. For the most part, though, he's very happy with the software's performance. "I would not want to go back and do it the old way," he says.
Better than a drafting table
SolidWorks Corp. is also fundamentally a CAD company, according to manager of product management Fielder Hiss. He notes that traditional, two-dimensional CAD drawings are still the norm for a majority of mechanical designers. However, given the complexity of elements, such as moving lifters, three-dimensional design capability can be a significant advantage. Done properly, it avoids building a system only to find out that a moving arm runs into something when fully extended.
So SolidWorks' software offers 3D capabilities and dynamic assembly motion. Using this technology, a virtual mechanical arm, with multiple linkages, can be constructed with software and then operated to mimic reality. "You can 'push' on parts and see exactly how they would move in the real world," says Hiss.
Other software features include collision detection; an alert is sounded if an arm attempts to reach through a solid object, like a keyboard. This simulation includes such factors as the strength of a boom as it's extended, addressing concerns about load handling.
The key to the simulation is model authenticity. Hiss says that SolidWorks software uses finite element analysis to assure accuracy, but hides details so users aren't confronted by daunting mathematics.
He also notes that ease of use of 3D CAD software has increased since its introduction decades ago; but he added that it still isn't as simple to use as it should be.
Software from Tecnomatix Technologies (acquired by privately-held UGS Corp. in 2005) goes a step farther in virtualizing the real world. It adds logical behavior models to 3D, mechanical kinematic-modeling. It allows PLCs and other control elements to be simulated with the goal of creating a virtual process matching 95% of the real world procedure.
This capability grew out of Tecnomatix's automotive industry work, explains UGS digital-manufacturing solutions marketing director Ron Yosefi. One of the drivers was the accelerating pace of product introductions; product launches were rising from 0.9 annually, circa 1988, to 2.5 per year around 2004. Time to market had to be slashed while the complexity of manufacturing soared, with the number of robots in a zone going from one or two up to 12 or more.
For this complex automation design, Tecnomatix advocates virtual commissioning. This, explains Yosefi, is a two-track method in which the entire process is reproduced inside the software with such authenticity that desired outcomes can be checked and error conditions also can be verified. "For example, we can use the HMI to define that a specific robot is down. We click on a button, the robot goes down, and we can see how the system continues to behave," he says.
Yosefi adds that the traditional approach, which is to actually build the system and then work out problems, is still widely used. However, he has seen increasing use of virtual commissioning. For example, BMW's Spartanburg, SC-plant recently used the technique for the first time in automating a manufacturing process.
Lost in translation
For complex automation designs, the two-track method of virtual commissioning allows an entire manufacturing process to be reproduced virtually to such a high degree that desired outcomes can be checked and conditions verified.
While CAD has been incorporating additional capabilities, other software advances have made designing automation control logic easier. Consider the nearest golf course. There the grass may be green thanks to a system from Flowtronex PSI Inc. The company makes pre-packaged water pumping systems controlled by a PLC equivalent.
Flowtronex electrical engineer Scott Smith says changing the traditional ladder logic found in control systems isn't easy. This became a significant challenge when Flowtronex had to switch from one PLC to another as customer demands required more memory. Rather than struggling with ladder logic, Flowtronex converted its automation software to CoDeSys, a cross-language platform, to handle all of the PLCs' standard, IEC-61131-3 programming languages. Improved programming productivity benefits, notes Smith, were highly subjective, but nonetheless real. "We probably did it twice as fast as we would have done it otherwise."
There are some aspects he'd like to see improved, most notably in the translation between internal and external addresses; on the whole he's happy with the platform. CoDeSys—developed by 3S-Smart Software Solutions—was supplied to Flowtronex by Wago.
Common code umbrella
Besides the software, 3S runs an automation alliance tying different hardware manufacturers together under a common code umbrella. Controllers programmable by CoDeSys interoperate without any hardware intervention, says Roland Wagner, engineer and marketing manager for 3S. All that's needed is a target support package, which consists of a target driver and library-like target-specific files. Then users select the editor from a list that includes the IEC editors IL, LD, FBD, SFC, and ST.
"The engineer has all these editors available for programming. For every POU (programmable organization unit) he can decide which editor to use," says Wagner.
When the code is ready to be executed, it's compiled by one of CoDeSys' integrated native-code compilers and the assembled application is then downloaded to the PLC. It's then ready to execute and debug.
Another frontier for automation software improvements lies in the interface, both for humans and machines. One example is Hoffman Estates, IL-based Bosch Rexroth Corp.'s WinStudio product that provides manufacturing execution system (MES) and supervisory control and data acquisition (SCADA) capability for supervisory and performance monitoring functions.
It also allows programmers to freely customize the human-machine interface (HMI) for a specific application. According to Rami Alashqar, Bosch Rexroth product manager, a tiered licensing structure for the software is a recent development. Thus, for very small installations, it's very inexpensive or even free.
Create in Windows CE
In another market-driven change, Alashqar notes that WinStudio can now create software in Windows CE—an OS that has grown in popularity with use of systems without hard drives. Avoiding rotating storage media makes systems more reliable and less expensive than a regular PC. So software developed in WinStudio now has new flexibility. "The software now can create screens for both the PC- or CE-based systems, and it's the same," says Alashqar. "You can just change the target."
Schneider Electric's software augments PLC programming by offering tools to work with the embedded Web servers found in the company's PLCs. The latest version of the company's FactoryCast tool, dubbed FactoryCast HMI, supports a host of Web standards, such as XML and SOAP for data exchange. The HMI also connects to SQL and Oracle databases, as well as Java-based scripting languages. Thus the design of automation systems and PLCs can be done by anyone familiar with the standards, which means just-out-of-college engineers can develop an HMI.
On the factory floor, these capabilities allow free flow of information from PLCs into corporate management systems. This exchange takes place without the need for intermediate PCs, software, people, or organizations. As Richard Hutton, Schneider Electric's U.S. automation product manager, says, "It eliminates a layer of hardware and software that had been in place before."