| When you need to connect or control industrial devices, there are many choices available. Sometimes, it makes sense to connect devices directly to an industrial PC (IPC) equipped with a multiport serial board. Other times, devices can be connected to a device server that is then connected to a network. In between these options is the embedded computer. Learn about using embedded computers for industrial applications below.
When is embedded computing appropriate?
An embedded computer is a compact, programmable platform that collects, stores, and processes data from attached devices. They are used to perform specific computing or processing tasks that do not require a full-fledged PC. Different processors, operating systems, storage capacities, form factors, and device interfaces are available depending on the specific application. Embedded computers are often used as local device controllers, protocol converters, or data acquisition servers that are accessible from a central management network.
One way to understand the role of embedded computers is to compare them to other device networking options. For example, suppose you wish to incorporate a traffic control device into an intelligent transportation system that is connected over Ethernet. One solution would be to use an RS-485 device server that makes the device accessible from a network host. Any computing or processing of the data would have to be completed by the network host itself, since the device server handles data transmission only. If the traffic device communicates using a different protocol than the rest of the system, all network hosts will need to be able to seamlessly switch to that protocol for that device. Multiply this scenario by a number of different devices and protocols, and the system can quickly become unmanageably complex. Generally, a device server would be suitable if only straightforward data exchange was required.
Another option would be to place an industrial PC on site that would connect both to the network and to the traffic device. The PC could be programmed to convert between the protocol used by the device and the protocol used by the management system. However, it is not very practical or cost-effective to use full-fledged PCs to handle a specific, dedicated computing task such as protocol conversion. In addition, industrial PCs are not suitable for many applications due to their size, power requirements, and limited ruggedness. An industrial PC is designed more to provide a powerful, centralized platform that requires human interaction or sophisticated software.
For this kind of situation, embedded computers provide the ideal solution. Their small size and rugged construction means they can be placed at almost any site to help manage devices, automate tasks, process or store data, and provide a connection to a network. As a computing platform, the specific functions of an embedded computer can be completely customized as needed for an application. They are designed as a cost-effective way to integrate or manage industrial devices for applications and locations where an industrial PC would be overkill or impractical. For large systems, embedded computers provide impressive versatility, making it easier to manage many different devices and protocols.
Examples of embedded computing
Embedded computing has already proven enormously useful for a diverse set of applications.
Many vending machine operators take advantage of network technology to monitor their machines from a single location. While newer vending machines may already have built-in Ethernet capability, older vending machines can rely on dedicated embedded computers to be connected to the network. Embedded computers can also be used to help integrate vending machines that use conflicting protocols. With seamless conversion between protocols, the management software does not have to go through expensive redevelopment.
At a hospital, there are many devices that are used to collect vital biometric data from patients. Devices or systems may be proprietary, and it can be challenging to get them to communicate with each other or with a central database. Embedded computers can be used to simplify the system, acting as a common connection point for multiple devices and allowing different protocols to communicate with each other. Data can also be converted into different formats as required by the central management software. For example, the embedded computer could convert the readings from a heart monitor into a spreadsheet-friendly format.
Advances in technology, such as cellular communication and GPS, have improved the efficiency and effectiveness of modern fleet management. Proprietary vehicle tracking devices can be expensive to use, and it can be difficult to incorporate their data into a central database. An embedded computer with a cellular connection provides the flexibility to handle any GPS device and any management system. Instead of relying on data as provided by the GPS vendor, the embedded computer can be programmed to convert the data into the most useful format for the central server. The control center can easily obtain live information on every vehicle's location over national cellular networks, without being tied to any proprietary system or to any vendor.
Differentiating between embedded computing solutions
 Embedded computers come in different shapes and sizes, and can offer a wide range of different features. Careful consideration must be given to what needs to be accomplished and what the embedded computer will be connecting to. For many applications, using an embedded computer and another dedicated networking product provides the best combination of flexibility and cost effectiveness.
What kind of device connections are needed? Embedded computers provide different combinations, types, and quantities of serial, USB, and Ethernet ports. Is RS-485 required? What about sensor connections? Can an external display be attached? Don't forget to consider what kind of connectors are required, especially if space is very limited. If necessary, you can look for a single unit that provides the exact combination of device connections that is needed. However, in many cases, it may be more effective to use the embedded computer in combination with a hub or adaptor. Some expandability can also be incorporated into the design of an embedded computer to achieve flexibility for future growth.
Since embedded computers are not designed for critical, long-term storage or heavy computing, RISC-based CPUs and Linux-based operating systems generally provide sufficient processing power for most embedded applications. However, embedded computers are certainly available for other operating systems, such as Windows CE or Windows Embedded, and Intel x86-based processors are also available. The selection will depend on the application, the type of management software being used, and the availability of qualified programmers. x86-based embedded computers offer exceptionally powerful performance and may even support VGA display, whereas CISC-based embedded computers offer superior ruggedness, smaller sizes, and lower power requirements. Other factors to consider include how much memory and storage space are available on the embedded computer, and whether or not they can be expanded.
Will the embedded computer connect to a central management system? If so, how? Although embedded computers can be used simply as lightweight standalone controllers, they are more typically used to integrate devices into a larger network. An Ethernet port should be built in, and dual Ethernet should be supported if network redundancy is required. For certain applications, it may be useful to connect a modem to a serial port on the embedded computer, to serve as the main or alternate connection to the central server. If the embedded computer has a built-in PCMCIA slot, a WLAN or cellular card can be used to provide wireless connectivity to the network. Embedded computers may also be designed with native WLAN or cellular support.
Form factor can be a crucial factor for embedded computing applications. Devices may not be easily accessible, and space may be very limited. Many industrial devices are mounted in cabinets or mounted on DIN-rails, 19-inch racks, or directly to a wall. Size, weight, power consumption, and mounting options can determine whether or not an embedded computer is suitable for an application. Some applications may even require that the embedded computer be mounted within another device.
With many industrial applications, the ruggedness of construction is also a critical issue. Inherently, embedded computers offer superior ruggedness compared to industrial PCs. With features like fanless operation and solid-state storage, certain models can achieve even higher MTBF values for critical, unmanned applications. For particularly harsh environments, it is possible to find embedded computing solutions that offer resistance to extreme temperatures.
In addition to these basic items, there are a large number of other considerations that depend on your particular needs and application. For example, how is the embedded computer configured or monitored? Is a control panel provided? Does it connect directly to a display and keyboard? How easy is the embedded computer to develop for? What is the software platform? Are programming libraries provided, and if so, are they comprehensive and easy to use? For issues that are important to you, be sure to check the specifications of the embedded computer and contact the manufacturer if necessary.
Conclusion
One of the difficulties in connecting industrial devices to control and management networks is the incredible variety of devices, protocols, connectors, and media that need to be connected. Embedded computers can provide the versatility and flexibility to handle almost any type of connection and protocol. For applications where dedicated hardware is too limiting and a full-fledged PC is too cumbersome, an embedded computing solution may just be right for you.
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