May 18, 2008

Mesh Network Success Stories

Industrial Monitoring

The Sensicast Wireless Sensor Networking Platform can provide a cost effective solution for monitoring the state of manufacturing and industrial processes. A WSN supplements existing control facilities by allowing for the measuring of manufacturing properties that with other "legacy" systems that would be cost prohibitive to retrofit into an existing facility.

Examples of using the Sensicast Wireless Network include the monitoring of motor vibration, and temperature for determining whether a machine is running optimally.

Industrial Motor Condition-based Monitoring

Electric motor energy consumption accounts for 23% of all energy use in the United States and 62% of industrial electricity usage. Currently, only the largest, most critical motors are monitored. Leveraging Sensicast's Sensor Networking Platform with the SensiNet™ Networking Protocol for use in industry's typical high multi-path RF environment, it is possible to provide an economic solution for wirelessly monitoring motor operating core temperature - for all classes of motors, creating an enormous opportunity for energy and cost savings.

125° F is the “cool period” for Sensicast sensors in a steel mill

There are few places more inhospitable to a sensor than a steel plant. Extreme temperatures and harsh chemical, metallurgical, and mechanical processes make any monitoring a challenge.

Yet process monitoring is critical to a steel plant’s profitably. Tough competition in the world steel market holds prices down. Any unexpected maintenance shutdowns reflect directly on the bottom line.

At a point in steel making, electrical current often arcs to the sides of the furnace. This super heats the furnace wall, sometimes overloading its temperature control mechanism. If the cooling system is allowed to fail, the molten steel could burn through the walls of the furnace in a matter of minutes, allowing molten metal to pour out onto the shop floor, endangering workers’ lives and millions in equipment. Then, needless to say, the plant would be down for a significant period of time.

For one major steel manufacturer, it was critical to find an accurate and cost effective way to monitor and record temperature fluctuations within the water jackets of their giant furnaces. After much research, they chose Sensicast wireless mesh network temperature sensors.

With 24/7 production, there was almost no downtime to install or replace the sensors. They had to be placed or replaced quickly during a brief cool period in the melting cycle. Even during these “cool” periods the temperature at the sensor site measures over 125° F!

The need for a quick installation, the high heat, and difficult positioning made installing wired sensors impossible. Plus, molten steel splashing around would vaporize any wires it touched!

Simple traditional wireless monitoring techniques were out, too. Strong magnetic and electrical fields, plus the large masses of steel would interrupt their transmissions, causing communication outages. In an application where a minute’s delay can mean disaster, this was not acceptable.

Sensicast H900 RTD nodes were placed between the inner and outer walls of the furnace. They were able to withstand the heat from melting steel, wide temperature swings, powerful magnetic fields, water spray, and vibration.

The brutal environment required a flameproof wrap, plastic water barrier and sturdy metal box to protect the sensor. These presented additional challenges for the wireless signals. But the Sensicast signal was able to punch through the protective shielding and relay its sensor data clearly and reliably.

SensiNet smart mesh networking routes data around any temporary trouble spots that might occur. Frequency hopping lets the H900 nodes search out the best channel for clear communication. This insures a constant and accurate flow of information to the plant’s maintenance and management teams.

Impressed by the reliable operation of the initial Sensicast monitors, the steel plant has since installed a Sensicast OPC system to deliver data directly to the PLCs. The company depends on this critical information to handle preventive maintenance more efficiently, eliminating the unscheduled downtime that can turn a profitable steel plant into a loser.

Into a nuclear power plant with B&B Electronics 802.15.4 wireless

Lloyd Pentecost, Maintenance Engineering at the San Onofre Nuclear Generating Station in California, searched for a method to monitor large secondary plant motors with a wireless mesh networking system.

Monitoring temperature of pump motors gives one indication of the operating conditions or "health" of the 2500 horsepower motors. If a motor were to fail unexpectedly, the plant would operate at only 80% capacity for a number of days, resulting in losses that could exceed $400,000. Collecting and analyzing motor temperature data in real-time allows action to be taken before a catastrophic failure occurs.

As the monitoring system plan developed, it was decided a new wireless data communication was called for. Avoiding new cabling would save initial installation expense and improve life-cycle and system ROI considerably. Pentecost required a system that would be reliable in his RF noisy environment, and meet demanding security requirements, while providing a path for future expansion.

An 802.15.4 wireless mesh network from Sensicast Systems was selected. "Evaluating various wireless technologies, Sensicast's networking platform provided the right set of features for the job," Pentecost said. "With battery powered sensors, no power wires are needed. It has excellent performance and range compared to the other technologies we tested."

As part of Pentecost's system, B&B Electronics is supplying custom RTD to 802.15.4 wireless converter nodes. They will connect to embedded RTD sensors and convert their analog signals to RF signals for the wireless network.

IEEE 802.15.4 is just one of the wireless standards in which B&B Electronics is fluent. Contact us for off-the-shelf or custom products.