Gary A. Mintchell, CONTROL ENGINEERING
KEY WORDS PC-based control Machine control Software for control Flowchart programming Simulation Imagine a product design, completed in software, and rendered in 3-D graphics. This rendering allows designers to strip away layers to view and work on components underneath. Next, manufacturing engineers can design the machines, fixtures, and processes required to produce components and completed ...
Not too long ago the idea of a machine dialing a maintenance technician's cell phone to call for help seemed far fetched. Then came the great success of Palm spawning the "palm top" market. Research In Motion's Blackberry e-mail device was next in the commercial hit parade. It is only natural that engineers using these devices for part of their business life would ponder how to exploit them fo...
Engineering conferences and publications thrive on controversy. There's nothing like a good religious debate to get one's blood flowing, and some engineering debates assume a religious air. There are the "fieldbus wars" and the "PLC vs. DCS vs. PC-based control" arguments. Technology and competition are combining to put a "double whammy" on these arguments.
A healthy manufacturing sector is essential to the health of all of the world's economies. Yet, manufacturing ended 2001 in the U.S. with its 17th straight month of decline, although signs of a recovery in 2002 are popping up. Forecasters predict that when this essential market rebounds, it will do so with fewer people employed.
Engineers needed a better way to move data from I/O devices through controller data tables to their HMI/SCADA (human-machine interface/supervisory control and data acquisition) software. Traditional methods were limited to moving blocks of bits from Remote I/O or other devices over a proprietary network or a slow serial network.
Systems theory requires studying the whole to learn about the interconnectedness of the parts, says Fritjof Capra in The Web of Life, rather than just the Cartesian study of parts. "Ultimately, as quantum physics showed so dramatically, there are no parts at all. What we call a part is merely a pattern in an inseparable web of relationships," he says.
Intelligent sensing for discrete manufacturing is finally coming of age. With cost of embedded controller chips on a continual decline and performance ever increasing, manufacturers can apply them economically in smaller packages. Meanwhile, advances in vision system software have reduced complexity to the point where it no longer requires a Ph.
Software programming no longer entails sitting before a blank screen and either entering contacts and coils or typing arcane commands and keywords that become long strings of spaghetti in ladder or text. Today's tools aid program organization and provide powerful command sets that make complex control easier and faster to accomplish.
Imagine designing a packaging line or material handling system with the control all in one package rather than separate logic control, motion control, vision systems, and bar code over RS-232. Real-world data are sent directly from the control program to a SQL database for analysis, selective sharing with customers or suppliers, and production and quality reporting.
KEY WORDS Software Manufacturing execution systems (MES) Enterprise resource planning (ERP) It used to be so easy. Of course, it didn't look like it at the time. All a control engineer had to do was automate a piece of machinery, maybe a production line, or a process. Now, there are more pressures.