Articles and Technical Papers

Wireless video applications in industrial environments

Randy Maes
Director of Technology
Data-Linc Group
See also Data-Linc's SAA-V 54Mbps solution for video and SCADA on the same netowrk in both the 900MHz and 2.4GHz license-free bands.

Wireless video networks in an industrial environment can be a challenge to implement. Video requires a large amount of bandwidth to function effectively. Radios used for data transfer within the wireless network are faced with environmental obstacles germane to industrial applications. Combining the two to create a wireless video network requires careful consideration of capabilities and limitations. The following is a general overview of video technology, radio technology and the union of these components to create a network in industrial environments that will perform to expectations.

The video technology

Early development of video technology on an Ethernet network revealed a problem. Ethernet was capable of the bandwidth necessary to support video, but the network was frequently overloaded and would run little else. This video technology was not conducive to real world applications and the requirements surpassed many established components of networks such as the Internet, which at the time was considered fast at 56K. As a dedicated application, the technology worked but to be marketable and established as a component of a network, be it for office or field use, the bandwidth consumption had to be reduced. Because of this, most network cameras and servers now support a variety of ways to adjust the bandwidth such as limiting the frame refresh rate, digital storage and compression. Digital storage would allow images to be downloaded for viewing at full speed thereby not requiring the real time bandwidth occupation. Compression would allow for many different image sizes and qualities. The smaller the image size and the lower the image quality, the smaller the amount of bandwidth required.

A majority of wireless video applications utilize products ranging from simple network cameras (a camera with an Ethernet port) to high-end video servers with 20 plus analog video inputs. In most cases network cameras are accessed via a web browser while the video servers are usually accessed via proprietary software.

The radio technology

Radios designed for industrial environments should be capable of high reliability over a long range. Reliability not only means clean and complete data transfer, but also a secure network component. Industrial radios have a limited bandwidth of around 100k. At the other end of the spectrum are radios that provide a higher bandwidth. These radios do so at the sacrifice of range and reliability. An example is an 802.11 radio with 1 to 55 mbps bandwidth capability. The high bandwidth capability comes, by design, at the cost of range and reliability exponentially.

It then becomes a process of identifying the most crucial system requirements. In many industrial applications a wireless video network is chosen for remote monitoring where the laying of cable is cost prohibitive and the speed at which the data is transferred is not as important as the range/reliability of data communication. If the objective is solely to transfer data at a short range and a fast rate, then the higher bandwidth radio may be the best option. It is a matter of overall system requirement analysis.

Wireless video network

Most network video equipment has been designed to occupy lower bandwidths to ensure viability in system networks. Ethernet radio modems have become a logical solution for industrial applications due to range/reliability requirements and Ethernet as a growing network standard. The wireless aspect adds yet another degree of gain due to low installation investment and system architecture flexibility. Range capabilities of 25 miles (farther with directional antennas and repeaters) create network options that can work for most applications.

It is common to become focused on one detail when making decisions about network components. There are many considerations and requirements involved and each component affects the others. When creating a wireless video network for industrial applications, the final objective should always be kept in mind— ensuring that the most applicable components are brought together to form a network that performs to expectations.

Data-Linc wireless modems are designed for industrial environments and are capable of data transmission over a long range with high reliability— clean and complete data transfer with a secure network component. Read about the security Data-Linc's radio modems provide in the article "Data-Linc Group SRM Series Wireless Security: Understanding Wireless Modem Data Transmission." See also our SAA-V 54Mbps solution for video and SCADA on the same netowrk in both the 900MHz and 2.4GHz license-free bands.

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