Weighing Wireless Benefits

Nov. 11, 2007
A newsprint producer is saving $150,000 annually, thanks to wireless links from its remote scale house to its mill.

In the commodity pulp and paper business these days, the ability to survive can come down to one thing—remaining a low-cost producer. That’s certainly true for the White Birch Paper Co.’s Bear Island Division, Ashland, Va., a producer of newsprint. “This is a tough market right now. In this industry, you have to be a very low cost producer in order to survive,” observes Robert DeJong, electrical and instrumentation supervisor at the Bear Island facility.
While paper companies often look to manufacturing processes to find cost savings and efficiencies, DeJong recently took a longer view—all the way to the mill’s remote scale house, where truckloads of wood chips, whole tree length wood and chemicals are weighed as they enter and exit the plant.

Data losses

For years, the scale house was plagued with weekly unplanned interruptions in its telephone line connection to the company’s network server. “All of our computer communications were going over an old buried phone line that was marginal at best,” says DeJong. “Whenever it would rain, we would lose connectivity with the building.” Dial-up modem connections sometimes failed as well, while lightning strikes were also often a cause of downtime. The communications disruptions caused costly delays in delivering the materials to the mill.

“Typically we would lose data about once a week when we were using the telephone lines,” DeJong says. “We would have to reset the link and then spend four to six hours to reclaim the data. That slowed the trucks down and the drivers didn’t get paid on time.”

In 2004, DeJong decided to take advantage of a new wireless local area network (LAN) technology from Siemens Energy & Automation Inc., the Alpharetta, Ga.-based automation supplier, as a way to improve communications and to help automate the scale house process. “We were already using Siemens industrial Ethernet in our mill for our control network, and we’ve been impressed with the reliability and robustness of their product,” DeJong relates. “So when their salesman told us about their wireless solution, we decided to give that a try too.”

Immediate savings

That decision has paid off handsomely. By replacing the phone lines with the Siemens Scalance W wireless LAN system, DeJong says the Bear Island operation immediately began saving $150,000 annually. Indeed, according to DeJong, the wireless system “paid for itself in the first three months.”

Part of the savings comes through improved efficiency. The wireless system “allows us to support the computer at the scale house without having to send somebody out there,” says DeJong. “And we’ve now got reliability of data transfer, so we’re not losing or questioning whether or not we’ve lost data.” Labor cost savings are also a big part of the payback. The scale house previously required “at least two full-time people” on site for operation, DeJong notes. But today, thanks in part to the wireless system, the automated weigh station now operates unmanned.

With the new system in place, trucks entering the station first pull into an inbound scale that automatically weighs the truck and all of its contents. Each driver receives a ticket and scans it into the automation system. The information is wirelessly communicated from one Scalance W access point and directional antenna mounted on the exterior of the facility to another access point at the mill’s servers about 1,000 yards away.

The Scalance W access point’s enclosure is designed to withstand the harsh environments often found at paper mills, including dust, water, vibration and temperature extremes. “Because of its rugged construction, Scalance W is ideal for outdoor applications,” says Raj Rajani, Siemens Ethernet infrastructure product manager.

After the shipments are unloaded at the mill, the drivers return to an outbound scale at the station and the system automatically updates the database through another Scalance W wireless access point. The calculations are immediate and the truck drivers’ payments are instantaneous.

Workload reduced

“Since we have gone wireless, we have achieved better reliability and speed,” DeJong says. “We are also saving time in the IT (information technology) department by reducing the workload to correct communications issues and loss of data.”

Two additional Scalance W units are also being used to enhance wireless communications at the mill’s engineering station for an ongoing turbine construction project. DeJong says he considered a number of alternatives when deciding to replace the phone lines between the weigh station and the mill’s servers. “We looked at the possibility of burying fiber optics out there, but we would spend approximately $12,000 to go 500 yards,” he says. “With the Scalance W system, once we hit a network node, we are back onto our network.”

DeJong says that the mill has yet to experience any unplanned downtime linked to the communications system since the wireless system was installed. “When we put it in, we were concerned about reliability,” he notes, “but that has proved to be the least of our worries.” He points to one example when an employee left the control panel open during a rainstorm. The box filled up with water, but the wireless unit kept operating.

“The Scalance W equipment has been bulletproof,” DeJong says. “We are planning to add more access points to the system. Right now, we have a portal crane that crosses back and forth in the antenna field and we plan to add another wireless connection to that unit to better track our wood.”

For more information, search keyword “wireless” at www.automationworld.com.

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