Equipment Condition Monitoring Goes Wireless

Equipment condition monitoring (ECM) for rotating equipment is a well-established field that is decades old.

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The practice is to take vibration measurements of machine shafts or bearing casings. The magnitude of vibration is compared with historical baseline values to detect changes in equipment condition. In addition, practitioners examine the component frequencies present in the signal from the sensor, which may correspond to particular mechanical components of the machine. The objective is to identify signatures of impending problems and perhaps their root cause in time to enable preventative maintenance action, rather than running the equipment until a failure occurs.

From an economic standpoint, continuous ECM has penetrated only a small fraction of the rotating shafts found in process plants. The high cost of permanently mounted sensors and continuous monitoring systems have limited its penetration to only the most critical 1 percent to 5 percent of installed rotating equipment. Discrete manufacturing operations, which usually have many more, though smaller, rotating shafts, are even less likely to have installed continuous monitoring. Instead, common practice is to use handheld systems to capture periodic vibration signatures, which (hopefully) are quickly analyzed for problem indications.

Several suppliers have very recently introduced new products intended to improve this situation. The rush began last September, when Emerson Process Management introduced a wireless vibration transmitter at its Emerson Exchange user event. Emerson had been working on small-footprint condition monitoring solutions for some time with its CSI products, and wireless sensing was an obvious extension in that direction.

A few weeks later, GE Energy also introduced wireless condition monitoring—the Bently Nevada wSIM system—at the 2007 ISA Expo. GE added the extra twist that sensors could be powered either by batteries, or alternatively, by vibration energy harvesters built into the sensor packages. The use of vibration energy harvesting had been mentioned as one of GE’s visions for its wireless research (which received partial sponsorship from the U.S. Department of Energy). At the same time, GE also announced that these new wireless vibration sensors had been tested and deployed at the massive Ormen Lange gas project in Norway.

A few weeks later, Honeywell introduced a wireless Equipment Health Monitor (EHM) for its OneWireless portfolio. This offering used sets of wireless sensors, which are networked to a Honeywell OneWireless mesh network. The analytical capability is provided by a partnership between Honeywell and SKF, the well-known ECM supplier. Honeywell also assembled a “starter kit” for its solution, consisting of the sensors, gateways and software needed to monitor four machines. In addition to adding wireless sensing, the EHM package enabled Honeywell to promote the 802.11 compatibility of its OneWireless infrastructure, and the incremental value of that infrastructure, once installed.

Solve problems

The most valuable ECM solutions will enable manufacturers to spend less time analyzing and managing data, and more time focusing on exceptions and important findings that automated analytics uncover. In addition, collaboration and data sharing among plant personnel, in-house ECM experts, rotating equipment suppliers and consultants will likely become an important future activity. The expansion of ECM brought about by wireless technology may enable structural changes in the business as well, because it may become possible and economical for many more people to collaborate and deliver value in this domain.

ARC recommends that manufacturers include automated analytics and diagnosis, not just automated data capture, as factors in evaluation of new ECM offerings. They should use wireless systems to expand both internal and external collaboration in the ECM area. Finally, manufacturers should expect suppliers to deliver wireless vibration sensing along with energy harvesting soon.

Harry Forbes,, is Senior Analyst,
Automation, at ARC Advisory Group Inc., in Dedham, Mass.
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