4-page Case Study - Posted 11/7/2006
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Greer Company Ensures Safe, Productive Operation of 90-Ton Construction Cranes
The Greer Company, a leading supplier of electronics devices to hydraulic crane manufacturers, needed to develop the next-generation of its flagship product, MicroGuard, a Rated Capacity Indicator that prevents cranes from overloading and toppling. Greer turned to Applied Data Systems, a Microsoft® Windows® Embedded Partner, to develop a single-board computer running the Microsoft Windows CE .NET version 4.2 operating system. In addition to hard real-time performance, Windows CE provided the robust and reliable managed code environment required by an application that helps protect human lives. Access to source code allowed for faster development of custom interface drivers, saving Greer 12 months of software integration time.
Situation
The Greer Company supplies electronic devices that keep telescopic boom cranes operating at full capacity and within safety limits.
Capacity, in terms of tons per lift, depends on scores of variables particular to the setup and operation of the crane at that moment. Greer’s Rated Capacity Indicator keeps track of variables such as load weight, boom angle and extension, and even wind speed to maintain the crane’s safe operation at full capacity.
Because most job sites have only one or two cranes, their performance can pace the construction schedule. Downtime for the machine usually means delays for the entire site. Even more important, overturning a typical 90-ton crane can have disastrous results, particularly in urban areas where pedestrians may be nearby, so safety is a paramount concern.
One of Greer’s customers, a large OEM, requested a Rated Capacity Indicator with a color VGA display and real-time interfaces with industry standard controller area network (CAN) 2.0 buses.
Greer’s existing product line was built around an underpowered 8-bit Intel 8051 processor and a proprietary operating system, which was developed in-house and lacked even rudimentary tools.
To fulfill the customer request, Greer needed more processing power and a reliable real-time operating system (RTOS) that could read CAN bus variables 50 times a second and complete an entire program cycle, including complex model-based simulations, in one-tenth of a second. At the same time, Greer also wanted to limit the operating system footprint to just 15 megabytes.
Solution
Greer selected Applied Data Systems (ADS) of Columbia, Maryland, to integrate the new device. ADS is a Gold Level systems integrator in the Microsoft® Windows® Embedded Partner program.
With a firm of understanding of Greer’s requirements, ADS chose Microsoft Windows CE (32-bit) as the operating system for a single-board computer powered by a 32-bit Intel StrongARM processor. Windows CE not only had the real-time performance required to monitor multiple sensors and instantly interpret and display the data, but it also offered the Microsoft .NET Compact Framework managed code for enhanced reliability.
Access to Windows CE shared source code allowed ADS to view and adjust thread prioritization, which was critical in the development of real-time input/output (I/O) and CAN 2.0 bus interface drivers, as well as custom drivers for the color LCD.
A combination of Microsoft software—Windows CE Platform Builder, Microsoft Visual Studio® development system, Microsoft Visual C#® development tool, and the .NET Compact Framework—helped speed the overall pace of software development, enabling platform integration and application development to be completed in just four months.
Greer’s customer, a major U.S. crane manufacturer, has already installed over 75 of the tablet-sized devices on two different crane models that are performing on job sites around the world.
Benefits
Higher Return on Investment for Customers
ADS provided Greer with an application-ready system, with complete hardware and drivers supporting a full Windows CE application programming interface (API) and the .NET Compact Framework installed. A consultant developed application software to Greer’s specification, all written in Visual C# operating under the .NET Compact Framework.
The seamless connection among various Microsoft software, from Windows Embedded to Microsoft Visual Basic® development system to the .NET Compact Framework, allowed all of the developers on the project to collaborate and build innovative solutions to address customer requirements.
For example, calibrating a Rated Capacity Indicator used to take crane manufacturers several days of valuable assembly time. This meant delays in shipping and invoicing a product that can cost as much as U.S.$1 million.
Greer had a program written in Visual Basic, operating on a normal PC, that takes the manufacturer’s Crane Rating Manual—which indicates rated capacity for every configuration of boom extension and angle, counterweight, footpads, and so forth—and puts it on a Compact Flash (CF) memory card. The CF card is inserted into a reader built into the display unit. This reduces factory calibration time to less than a day.
“For this highly complex real-time application and embedded hardware device, no third-party software was required for graphics, communication, debug, database, or anything else,” says Lawrence Ricci, Business Development at Applied Data Systems. “Everything we needed was inside the shrink-wrap of Windows CE Platform Builder and Visual Studio. By avoiding the costly licensing fees and custom integration work required by other real-time operating systems, we estimate that Greer saved hundreds of thousands of dollars in development costs.”
Real-Time Application Performance
Greer’s Rated Capacity Indicator is a highly demanding application. The I/O and CAN buses interface to a dozen or more sensors distributed throughout the crane. The sensors monitor support footing placement, boom extension, angle, rate of swing, and so forth. Data is updated between 10 and 50 times per second. The application references the data against the Crane Rating Manual. This database, as big as a dictionary in printed form, is interpolated and used as a basis for calculations to determine the “overturning moment” of the crane. This is displayed to the operator as a clear “percentage of allowed” on the screen.
“Windows CE provided more than enough real responsiveness to manage multiple sensor inputs, while simultaneously handling complex algorithmic calculations and database lookups,” says Ricci. “Developers need to ask themselves what level of real-time performance they really need. In our many years of experience, Windows CE has delivered performance sufficient for 99 percent of all real-time embedded applications.”
Power Management for Fast Device Startup
Crane operators expect a great deal from the in-cabin device. It must be able to stand unattended in a storage yard for months, yet still start up in an instant. Unlike many other RTOSs, Windows CE offers advanced power management features such as suspend and sleep modes. ADS developed the device drivers to take advantage of these power management features. ADS also engineered the device to boot straight to the Greer application, skipping the normal Windows startup screen and interface shell. This shaved valuable seconds from the startup time. The result is a device that powers up and is fully usable just seconds after an operator starts a crane.
“Thanks to Windows CE, fast startup is a significant competitive advantage for our device,” says Simon Worboys, Engineering Manager at Greer. “Imagine starting your automobile and having to wait a few minutes for the radio to warm up. That would be unacceptable. Just like car drivers, crane operators expect instantaneous responsiveness from cabin instrumentation. Some of our competitors’ Rated Capacity Indicators take up to two minutes to wake up, while our Windows CE-based device starts up instantly.”
Managed Code Enhances Reliability
By preventing workplace accidents, the Rated Capacity Indicator protects human life. It is a mission-critical application that demands reliability. Software “bugs” and defects are simply unacceptable. The system must run 24 hours a day, seven days a week for months on end, with absolutely no software anomalies. For Greer and ADS, the biggest challenge was solving the problem of “memory leak.”
Memory leak occurs when a program continues to use memory that it no longer needs. As a result, the program grabs more and more memory until it finally crashes because there is no more memory left. While this is tolerable for standard desktop computers, which are usually restarted daily, it is unacceptable in a real-time embedded system that demands operation 24 hours a day, seven days a week.
Programs written in Visual C# under the .NET Compact Framework can utilize a “garbage collector” function, which automatically releases memory from the application. ADS showed the application developer how to write wrappers so he could access the real-time I/O from Visual C# managed code. The result was one of the first-ever embedded systems to combine real-time processing with the reliability of managed code.
According to Worboys, using a Microsoft Windows Embedded Partner was the right decision. “We had tried this development project once before with an offshore company and it was disastrous,” Worboys says.
“There were language problems and delayed response time. The results were not good. The engineering support team at ADS was responsive, available, and understood each step of the project. With the Windows CE system from ADS, all the pieces seemed to drop into place,” Worboys concludes.
For More Information
For more information about Microsoft products and services, call the Microsoft Sales Information Center at (800) 426-9400. In Canada, call the Microsoft Canada Information Centre at (877) 568-2495. Customers who are deaf or hard-of-hearing can reach Microsoft text telephone (TTY/TDD) services at (800) 892-5234 in the United States or (905) 568-9641 in Canada. Outside the 50 United States and Canada, please contact your local Microsoft subsidiary. To access information using the World Wide Web, go to:
http://www.microsoft.com/
For more information about ADS products and services, call (800) 541-2003 or visit: http://www.applieddata.net/
For more information about Greer products, call (800) 346-5245 or visit: http://www.greercompany.com/
© 2005 Microsoft Corporation. All rights reserved. This case study is for informational purposes only. MICROSOFT MAKES NO WARRANTIES, EXPRESS OR IMPLIED, IN THIS SUMMARY. Microsoft, Visual Basic, Visual C#, Visual Studio, Windows, and the Windows logo are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries. All other trademarks are property of their respective owners.
Keywords: Automation Devices, Monitoring Devices
