Sensing the industrial world

By Bob Trebilcock, Editor at Large -- Modern Materials Handling, 12/20/2005

When systems integrators look for value from RFID beyond compliance, they often talk about combining the technology with sensor technology.

At their core, sensors are electronic devices that detect the physical characteristics of the world around them.

“RFID is a technology that’s all about knowing where something is located,” says Rob Conant, vice president of marketing and business development, Dust Networks (510-400-2900). “Sensors are all about knowing how something is. They take a parameter from the physical world, like temperature, and convert that to digital information. They provide a computerized representation of what’s happening in the world.”

The most common industrial sensors today are simple binary sensors. These communicate the equivalent of a yes/no or on/off response. Proximity sensors, for instance, detect the presence or absence of a characteristic that’s important. A photoelectric sensor detects the presence of light while other sensors detect metal or plastic.

Analog sensors, on the other hand, can provide more complex information, like temperature, pressure, speed, noise, vibration or some other characteristic that’s important to the operation of a machine, the quality of a process or product or the security of a work area. Combining analog sensor technology with RFID technology could allow a food company to monitor the location of a pallet of fresh meat along with the temperature in the refrigerated storage area.

While sensors have been used in the industrial world for more than fifty years, there is a need for more sensors as the use of automation expands. “If you’re required to operate your factory or distribution center 24 hours a day, seven days a week, it’s important to have a way of detecting a change in the system right away so you don’t shut down a line or damage a machine,” says Helge Hornis, manager of intelligent systems at Pepper1+Fuchs (330-486-0148). “In an automated environment, a sensor is the eyes of a control system on a process.”

Enabling that growth has been advancements in microprocessor technology. “Sensors are cheaper, consume less power and can be programmed with more intelligence than in the past,” says Hornis. “And because they keep getting smaller, you can now apply them in machines where it just wasn’t possible before.”

While the cost of the sensors is coming down, the cost of wiring them is still a barrier in many applications. But just as radio frequency technology enabled the expanded use of bar codes, voice and RFID technology, sensors may soon go wireless as well.

“In the sensor world, the cost of getting that information has been dominated by the cost of wiring the sensor network,” says Conant. “Using wireless networking technology for sensors creates a way for people to deploy access points over a large area without having to run dedicated cables.”