How wireless networks are changing industrial environments
IEEE 802.15.4 based wireless networks can be reliable, robust, and cost effective for many industrial, warehousing, and facility applications. These wireless networks transmit through walls and floors, reducing wiring and routing challenges, and making equipment placement more flexible and productive.
Wireless networks are transforming industrial plants and manufacturing operations globally. Based on the standard IEEE 802.15.4, this evolution from wired to wireless networks in industrial, manufacturing, and warehousing applications is primarily driven by the need to reduce costs, improve uptime, save energy, and improve workplace safety.
Those working in warehouses, factories, and industrial facilities are discovering that wireless networks can greatly reduce network installation and maintenance expenses. Because IEEE 802.15.4 wireless can transmit data throughout a plant, penetrating walls and floors, it eliminates wiring costs and cable routing problems, while placing fewer restrictions on the location and placement of equipment.
It’s also faster to install, which is another factor behind the move to wireless, particularly for factory floors that need to reconfigure manufacturing and assembly lines quickly and efficiently to ensure a minimal amount of downtime.
By using wireless to reconfigure or change the physical layout of an assembly line, the plant manager can simply move the machines to new locations and turn on the wireless network, eliminating the need to re-route or install cables.
Maintenance and repair costs are another challenge for plant managers that can be reduced by using wireless communications instead of cabling.
Switches play an essential role in industrial and transportation controls, monitoring the position and presence of doors, booms, and valves. However, wired switches and sensors are often a challenge to install and maintain, particularly in harsh environments or where wiring flexes frequently. In addition, traditional wires can cause tripping hazards or get damaged during normal equipment operation, thus causing expensive downtime.
Wireless switches help reduce maintenance costs because the equipment connections are less complex. By eliminating cabling for sensors and switches, plant managers can simplify troubleshooting. In some cases, using battery-powered switches and sensors removes the need to use any cables at all. Wireless networks also increase system reliability by eliminating the potential for continuity issues caused by wiring or connectors.
Additionally, wireless devices are simpler to replace or reconfigure. For example, there is no need to disconnect and re-attach wiring, which also eliminates the risk of incorrect wire attachment. In many cases, the installation of a new wireless network is less expensive and faster than replacing the existing damaged wire, which takes time to troubleshoot and replace, causing considerable downtime.
Wireless is not just for inside the factory. Wireless is often the best networking technology for outdoor applications, such as shipping centers, warehouse yards, lumberyards, airports, fueling stations, and more. This is especially true in large, open locations where underground cables are at constant risk from harsh environmental elements as well as the travel of heavy vehicles across them. It can take weeks to troubleshoot and repair a broken cable under a large driveway. In contrast, replacing it with a wired network may take hours and is much less expensive.
Industrial wireless backbone
The IEEE 802.15.4 standard is a robust wireless personal area network (PAN) that is specifically targeted toward the low-power, low-bandwidth networks commonly used in industrial monitoring and control.
Here's how it works: an IEEE 802.15.4 transceiver integrated with an industrial switch or sensor communicates to a monitoring receiver that can handle multiple switches in a star-configuration network. Every network, and each wireless device in the network, has a unique identification number that allows the device and its associated monitor to encode their signals. This ensures that the communications link between them is private and virtually immune to crosstalk from other switches or networks.
These 802.15.4 radios provide reliable connectivity in large indoor open spaces and/or outdoor installations with a relatively open line-of-sight between device and monitor. A 35-dB link margin ensures that minor obstacles or even heavy precipitation will not compromise communications. In some installations and depending on materials, the signal can penetrate intervening walls. This also prevents temporary outages when a truck or other mobile piece of equipment is moved between the sensors and the receiver.
The allowable operating range of an IEEE 802.15.4 radio is greater than 1000 ft (304 m). In extreme conditions such as heavy precipitation, the signal could be reduced by approximately 75 ft (23 m).
Because 802.15.4 devices draw so little power, they can be operated by industry-standard batteries, for reliable operation and varied installation options. They also eliminate the need for situation-dependent, unreliable, and expensive energy scavenging. A wireless sensor or switch may operate for several years without a battery replacement or re-charging, depending on the design.
Typically, the monitor/receiver unit in a wireless network can support either one device or multiple devices. For example, one receiver can support up to 14 remote battery-powered wireless devices. The controller can monitor sensor and switch status, signal strength, and battery levels for each device on its network. If a battery starts to die, or a switch gets blocked, the operator will know instantly and can take corrective measures.
Wireless on/off controllers are also available. Powered by batteries, these wireless operator interface devices can be located for easy operational access without spending a lot of time to connect them to the control network or to a power source.
More wireless industrial photos and links follow on the next page, including information on wireless interference, security, and flexibility.