Analog Devices Inc. has unveiled their MEMS or Micro-Electro-Mechanical System-based accelerometer technology at the Sensors + Test Conference in Nuremberg, Germany. The MEMS vibration sensor can track vibrations at frequencies of 22 kHz. This is especially helpful for sensing high-frequency vibrations in industrial equipment.
The MEMS technology from Analog Devices is unique in the sense that it uses two MEMS mechanisms placed beside each other. The arrangement helps to cancel out common mode noise, favoring only the differential mode noise. Vibration and shock sensors from ADI are small format sensors that enable equipment designers to build vibration-detection chips within devices for industrial process-control, rather than as add-on modules.
Most vibration sensors today are piezo-electric-based modules. They have two disadvantages—it is not possible to mass-produce them, and their range is limited to 5-kHz frequencies. On the other hand, ADI makes their accelerometers in CMOS processing lines, and they can mass produce them easily. Additionally, ADI can undercut the prices of piezo-based vibration sensors by about 50 percent. For instance, the prices of ADI vibration sensors are around $35 as opposed to piezo-based sensors at $70.
With manufacturers looking for whatever they can get for improving the production and efficiency of their equipment, MEMS vibration sensors from ADI are the right products in the right place and at the right time. Although, when comparing unit shipments, the industrial market is small compared to the consumer electronics market, revenue-wise, the former is incredibly important and offers better margins. MEMS sensors address identified needs within the industrial market sector, and therefore, provide tangible value.
In the case of piezo-based vibration sensor modules, the standard practice is to bolt them onto the side of vibrating industrial equipment. However, using the chip-based accelerometer sensor from ADI is simpler, as it is possible to integrate it right within the circuit board of the device when assembling. ADI is of the opinion that some piezo-based vibration sensor manufacturers may retrofit MEMS chips into their bolt-on modules. However, ADI also expects OEMs of industrial equipment to stop using modules and rather start integrating ADI MEMS chips directly into their pumps, motors, gearboxes, and other pieces of industrial equipment.
Industrial equipment manufacturers are increasingly using vibration sensors as these can sense on-coming failure before it happens. For instance, a deteriorating bearing will vibrate at high frequencies before it fails. As it nears failure, its vibrating frequencies will drop until it finally disintegrates totally, possibly causing damage to the rotor. This is why predictive maintenance is increasingly becoming popular.
The present trend in the industry is to move towards predictive maintenance from preventive maintenance. Early detection through predictive maintenance can cut down repair costs by as much as 25 percent. Waiting to repair equipment until something fails can push up the maintenance costs more than ten times. Compared to other predictive maintenance techniques such as ultrasonic analysis or infrared thermography, vibration analysis offers better return-on-investments, by as much as three times.
ADI offers its vibration and shock sensors in ceramic packages, available in 70g, 250g, and 500g ranges.