Wireless Connectivity Offers Solutions for Maintaining Applications Remotely
Wireless connectivity reduces cost and increases flexibility for connected embedded systems. Wireless-enabled PDAs are an increasingly appropriate means for test and maintenance.
ERIC REFFETT, NATIONAL INSTRUMENTS
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New developments in FPGAs—such as the ability to embed up to four PowerPC 405 processors, and include up to 10 Mbits of embedded memory—are being used today to deliver unprecedented performance to embedded systems. With all of the advances in what embedded systems can accomplish, it is important to also consider new technologies that connect these embedded devices to other parts of customer systems.
One of the most interesting areas is how these systems are increasingly maintained through wireless networks. By considering how wireless networks are used to maintain computer systems, embedded designers can produce better products for their customers. These products not only take advantage of the technical abilities of embedded solutions, but also provide additional value to customers by having attractive maintenance options built in.
Historically, computer systems have been connected by a series of cables that physically connect all of the components of the system together. This same network of physical cables makes it possible to remotely test and maintain many of these systems. However, the physical cables mean that the system has limited flexibility when being set up. The setup and maintenance of these systems is constrained to locations where cables can be run, and by how much shielding is required to keep the signals from interfering with one another. Solving these problems incurs extra expenses to design the system correctly from the start. Additionally, extra time must be spent to physically make all of the required cable connections.
Wireless networking technology has made it possible to perform maintenance on computer systems without the need for physical cables. Advances such as Bluetooth and 802.11x wireless Ethernet protocols free system designers from the constraints they have faced in the past in maintaining computer systems. Bluetooth communication operates using radio frequencies in the 2.4 GHz range to send data between Bluetooth-enabled devices at a current rate of 1 Mbit/s.
Bluetooth provides an easy-to-use experience for devices that are going to be within 30-100 feet of any other Bluetooth device. The nice part about Bluetooth communication is that you do not have to think about it. Part of the Bluetooth communication standard is that all Bluetooth devices must be able to recognize other Bluetooth devices and determine if they can “talk” to each other without user input. Therefore, if an embedded device has a Bluetooth connection point, it will automatically be able to use any Bluetooth network that it is near enough to communicate with (Figure 1).
By comparison, 802.11x networks also operate in the 2.4 GHz radio frequency range and are able to communicate across much larger distances—up to 3 miles or more with the new 802.11g protocol. In addition to this increased distance, the 802.11x protocol is an IEEE standard that is supported by hundreds of vendors, which in turn means there are lots of resources available to help configure a 802.11x network. The standard is also continuing to evolve to allow much faster communication rates than those that currently run up to 54 Mbit/s.
All network solutions make it possible to reduce system cost by allowing a central test server to remotely perform tests on several remote units, while also decreasing test time and expense because service personnel do not have to be sent to each unit being tested. Additionally, the broadcast range and communication speeds allow for more flexible system designs and a reduction of the costs associated with providing cables to each part of the network, and possibly shielding those cables.
These costs might seem insignificant until you consider how much cable must be run to connect all of the different access points of a large complex system such as an automotive manufacturing facility or typical office building. And then consider what costs must be incurred each time you change the layout of this system. The benefits in cost and test time reduction make devices that incorporate wireless technologies increasingly in demand.
The energy industry is an example of where these wireless technologies are already being used since it has many applications that require regular maintenance. Parts of these systems are located in areas where it is either difficult or dangerous to have physical equipment and cabling due to environmental factors such as extreme heat or radiation that would interfere with the testing and maintenance. In this situation, a wireless solution is not only ideal, but is actually required.
Coincidentally, these same locations are where embedded systems are used most frequently because they can be designed to withstand the interference and operate independently. The ability to easily connect the embedded components of these systems with the rest of the system for testing and maintenance is a valuable feature that many customers are currently required to build themselves, because not all of the system components are currently wireless-ready.
Manufacturing facilities such as automotive assembly plants also take advantage of the reduced costs of using wireless networks to maintain their systems. The testing and maintenance systems required for this type of facility encompass hundreds of system components that can literally span miles of production lines. Before wireless networks, each component needed to be either physically connected to the network with a cable, or some physical equipment was required to maintain the system. Additionally, each time the manufacturing area was reconfigured to accommodate new equipment or to produce new vehicles, the networking also had to be redone.
The ongoing costs associated with each configuration and the ongoing maintenance of all these applications is something that manufacturers historically accepted as part of doing business. Now, however, with the introduction of wireless networks, they are eagerly removing these costs. With wireless networks, the components of the entire system are easily connected to each other, and a central maintenance application is used to remotely test many different components. This reduction of cables increases the flexibility of the plant layout, and the reduction of physical test equipment offers a reduction in maintenance cost. These benefits are highly desired in large, complex manufacturing facilities.
Even with all the cost advantages the remote maintenance systems provide, some systems must be maintained and tested on-site, due to concerns such as lack of remote access availability, or special needs such as security restrictions. Even the very large 3-mile range of 802.11g will not be able to reach all areas, and some government specifications require no remote access be given to some equipment and that all maintenance be done only by authorized personnel. Therefore, equipment must sometimes be tested while it is out in the field, which means that the maintenance applications and testing equipment must be taken to the computer system to be tested. Military or aerospace vehicles, for example, require regular maintenance that must often be performed in remote locations and in secure areas where no network access is available. In order to perform the required maintenance to these vehicles, a physical inspection and portable testing equipment is required (Figure 2).
For these situations, maintenance applications can be designed for portable devices such as Personal Digital Assistants (PDAs). With more than 10 Million PDAs being sold per year, these devices are already commonplace tools for engineers. These miniaturized computers have 400 MHz processors, more than 64 megabytes of memory and expansion capabilities that give them virtually limitless flexibility. Many PDAs also have Bluetooth or 802.11 wireless Ethernet capabilities built in, which makes them uniquely suited for performing testing and maintenance on remote systems, storing the test data and later communicating that data with the rest of the testing system when an available network connection is available (Figure 3).
In order to build these portable applications, flexible software is required to design customizable maintenance applications, and then migrate this software to the PDA devices. With powerful, easy-to-use software, building these applications in the first place requires little time. Migrating these customized maintenance applications to PDA devices using a utility that converts for use on a PDA requires no work since the module converts the application for you. Leading-edge development tools like NI LabVIEW and the LabVIEW PDA Module make it easy to quickly develop these portable maintenance solutions and provide the open flexibility required to integrate these solutions into the rest of a networked maintenance system. Using COTS devices such as PDAs to handle these maintenance applications provides an ideal platform for taking testing systems into the field in a portable format to reduce maintenance and test time.
These applications are just a few of the areas already using wireless technologies that span industries ranging from manufacturing to biomedical and healthcare. As the bandwidth and security of these networks increase, so will the demand for all parts of computer systems to be able to take advantage of them. Considering the increasing performance of embedded systems, and the increasing demand for wireless maintenance solutions, adding wireless connectivity to embedded systems seems like a logical addition to make.
As a final note, there are already several ways of adding wireless connectivity to embedded systems and many are fairly easy to implement. For example, COTS components already exist to provide PC/104 to PCMCIA connections and there are many existing PCMCIA solutions for both 802.11x and Bluetooth protocols.