Cutting the Cord | Chemical Processing

Read how one company has been applying wireless technology where it makes sense to cut costs and make employees more productive

Share Print Related RSS
Page 2 of 2 1 | 2 Next » View on one page

The instruments wirelessly transmit measurements up to 2,000 ft. to a base radio connected to a control system or data acquisition device. Each base radio accepts the signals of up to 50 transmitters. The base radio provides Modbus or 4-20 mA analog signal output for flexible communications.

Eastman has begun field trials of wireless sensors, and so far they have worked well. They reduce the installation cost and time compared to traditional wired sensors.

Wireless technology is all around us, and offers many benefits. The prices for most wireless technologies have dropped so much that it pays to keep an eye on the technology, if not for work, then at least for home use. But if you go wireless, spend a few extra minutes turning on the basic security features to ensure your system is safe and secure.

Dave Hrivnak is mobile projects manager for Eastman Chemical Co., Kingsport, Tenn. Visit him at www.hrivnak.com.

Another promising area for wireless is in plant automation, starting with sensors. Honeywell has just released a new line of wireless sensors. The XYR 5000 line enables automated monitoring of variables in areas where traditional hard-wired transmitters are too costly, difficult or time-consuming to implement. I used to say that cellular wide area networks (WANs) did not work for chemical companies because the cellular companies place their towers and new technology in the population centers, while chemical companies tend to build their plants away from the population centers. Fortunately, we have found that is no longer the case. The major cellular companies have now built out their networks so they reach almost everywhere in the United States, including most chemical plant sites. Security is an area of wireless technology about which there is a lot of misinformation. The majority of security breaches are due to people installing wireless LANs and never turning on security features. If you enable Wired Equivalent Privacy (WEP) security, it is very difficult to break. Even basic home systems now allow you to use WEP and to turn off the broadcast of the SSID (Server Set ID, or the name you give your access point). Just look under the security section of the manual or check the online help function. Technically, WEP can be broken into, but it is not easy to do. You need a server with 4 GB of main memory running on Lynx, and also need to collect 500,000 packets between one laptop and one access point. To collect this in the real world is next to impossible. Those companies that want a higher level of security can run something like Cisco's LEAP or place their wireless LAN outside the base network and use VPN software to gain access.A wireless local area network (LAN) using IEEE standards is very popular technology for providing Ethernet connectivity without the cost and hassle of wires. There are several variations of 802.11 technologies. The pervasive "B" standard gives 11 Mbps of speed over a range of about 150 ft. in an office area, and 500 ft. in a typical warehouse or outdoor rail yard area. There is an "A" standard that is faster, at 54 Mbps, but rarely is the Ethernet link the bottleneck in overall system performance. The range of 802.11a is about half that of 802.11b, and it costs more, so there is little reason to use this version of the technology. There is a "G" version of the standard that is also 54 Mbps and has the same range and frequency of 802.11b. While there can be some benefit in an office area in which there are many mobile users, there is little need for the extra speed in a control room or warehousing area. Because most 802.11g systems interoperate with 802.11b, if the costs are close, you could hedge your bets with this technology. But if you do, check for 802.11b interoperability, as more than 90% of several million wireless LAN cards are 802.11b.
Page 2 of 2 1 | 2 Next » View on one page
Share Print Reprints Permissions

What are your comments?

Join the discussion today. Login Here.

Comments

No one has commented on this page yet.

RSS feed for comments on this page | RSS feed for all comments