"Users should identify and define the requirements of their planned wireless system and then determine when wireless makes sense. They need to look at the cost, reliability throughout and response of wireless, and compare it to hard wiring," says DeHaan. "An onsite RF path survey using the proposed equipment is very important and must be done before finalizing the wireless system design and purchasing equipment. Most wireless manufacturers will loan demo equipment for a few days of onsite testing. The onsite survey will help identify radio path problems due to obstructions, terrain, distance, etc., and will help to identify repeater locations if necessary.
"When a manufacturer claims a certain ‘range' for its products, this claim must be taken with caution because it's usually a maximum range in an optimal environment—in flat terrain between transmitter and receiver, with no obstructions or interference. The user must also recognize that higher frequencies offering higher bandwidth come with much lower range limitations and increased susceptibility to noise. When comparing products, users should look at the tangible performance values for each device, namely transmitted power and sensitivity, instead of the maximum range claimed."
Another way that users begin to approach wireless is by trying it out in the smallest, non-critical application in their facility—often just a couple of signals via one or two transmitters, antennas and receivers. Several suppliers offer very basic packages that rookies can use to experiment with wireless, and then scale up as they gain experience and knowledge about how wireless works in their facility and local environment.
In fact, Emerson's Smart Wireless field starter kit establishes an out-of-the-box, secure, self-organizing WirelessHART network that delivers greater than 99% communications reliability in the steel-and-concrete setting typical in most industrial plants. The kit also contains discrete switches and vibration and pH transmitters.
"This kit makes it very simple and low-risk to try Smart Wireless," says Bob Karschnia, Emerson's vice president of wireless technology. "Companies who've never used this technology before can quickly and easily begin to reap the same benefits gained by their peers who are already using Smart Wireless." To provide even more help, Emerson also offers its Smart Start onsite program to help users with their initial wireless experiments.
To more reliably monitor, diagnose and maintain water equipment and processes at its plant in Calvert, Ky., industrial gas and specialty chemical manufacturer Air Products (www.airproducts.com) recently installed wireless remote monitoring equipment and services from GE Enterprise Solutions (www.ge.com/enterprisesolutions), including sensor and wireless technology, software hosting, alarm notification, application expertise, and installation services. These connect to Air Products' water treatment data and help perform liquid level monitoring of the company's large tank operations, eliminating manual tracking and improving productivity by providing timely information on chemical inventories.
Basically, a submersible level probe sensor from GE Sensing and Inspection Technologies is dropped into each tank to collect measurements. Using GE Digital Energy's wireless MDS technology, the raw data is sent to a Trinity gateway, which serves as the field data collection point for each application. This gateway sends collected data to secure hosting servers managed by GE Fanuc Intelligent Platforms, where it's translated into online diagrams showing liquid levels and consumption rates. In addition, experts from GE Water are on call in the support center to help analyze information, resolve issues and drive continuous optimization for the business.
"This wireless system helps us to be proactive as we monitor chemical tank levels that support our water operations, and we can access it at any time from anywhere," says Bruce Marshall, Air Products' site manager. "Wireless monitoring allows us to check the water treatment systems that support our chemical operations remotely, and the system can automatically alert us when specified process conditions are reached," explains Marshall. "It ensures that we're getting the right information at the right time to aid in our decision-making for our operation."