Wireless: No doubts about IEEE 802.11n advantages, say Rockwell Automation, Cisco
IEEE 802.11n wireless protocol offers industrial automationnetworking applications better performance for control and automation, with throughputup to 6x existing wireless networks, better packet retry handling, plusbackward compatibility.
Wireless is about eliminating costbecause cabling can be unreliable. Further, IEEE 802.11n wirelessprotocol has additional advantages, including up to six times thethroughput of existing wireless networks, explained Paul Brooks,business development manager, networks portfolio, for RockwellAutomation.
Brooks and Dan Knight, Cisco industry solutions manager, during an Automation Fair presentation in November 2009, touted the benefits of wireless, saying that wireless makes people more efficient and effective. It helps locate people and equipment more quickly, and it makes video surveillance much more economical. And IEEE 802.11n is particularly well suited for industrial monitoring and control, especially in applications where cabling is impractical or might fail. Often, a combination of wired and wireless technologies can quickly provide the best possible implementation, Brooks said. In one of many examples provided, Knight explained how Metroline Greenhouses, with 5.8 million square ft, reduced inventory by 15%, improvement worker productivity, with same staffing.
Rockwell Automation has been working with Cisco on industrial Ethernet network, most recently using the Cisco unified wireless network. Brooks and Knight said the unified wireless network is architecturally flexible, can stand alone in an application, or can operate with a controller-based solution, with components, as needed, for the application.
IEEE 802.11n protocol ha s :
– Multiple input and multiple output (MIMO) capabilities, which increases fidelity.
– 40 MHz, packet aggregation (like carpooling), and multiple antennae capability, which can multiply throughput (more lanes on the highway);
– Fewer transmissions and acknowledgments, which helps with many control applications;
– Backward compatibility with IEEE 802.11a, b, and g in 2.4 and 5 GHz, for less interference and more channel operations; and
– Twice the reliability and predictability.
Enhanced testing, Brooks said, has demonstrated:
– Point to multi-point capability providing wire-speed performance through a wireless network;
– Packet aggregation of up to 19,000 packets per second;
– Zonal coverage to find non-overlapping channel. This is made possible with 21 channels using 5 GHz, compared to 3 channels in 2.4 GHz.
– Up to 300,000 packets/sec of data are possible using multiple radios and channels; and
– Radio frequency co-existence is possible, IEEE 802.11 b/g and n with IEEE 802.15.4. Four channels are available and the network will locate others as available in real time.
"For the right applications, this is very suitable technology," Brooks said.
Also read from Control Engineering :
– Transparent Wireless at Cano Petroleum ;
– Switch to industrial Ethernet switches; rugged advantages ; and
– Manufacturing convergence: IT, Ethernet drive integration, say Rockwell Automation, Cisco .
– Mark T. Hoske, editor in chief, Control Engineering www.controleng.com