Every machine has a service life. By monitoring the operation status of a machine using a smart sensor, any abnormality in the machine can be found in time, so as to replace parts in advance to avoid machine failures. This article will introduce a smart sensor solution, providing a smarter management environment for the Industrial Internet of Things.
Smart Sensor for Condition Monitoring
The core challenges of using mechanical facilities and scientific and technological systems today are how to improve the condition monitoring and diagnosis of machinery and optimize the overall system. This topic is not only aimed at the industrial field, but also plays an increasingly important role in other places where machines are used. In the past, machines were repaired according to a planned schedule, and if maintenance was delayed, a halt in the production line might be caused.
Now there is a smarter way to predict the service life of machines, that is, by collecting data from the operation process of machines and recording particularly critical parameters, such as temperature, noise and vibration, to help determine the optimal operation state and necessary maintenance time. This method can avoid unnecessary wear and tear, and can detect possible faults and their causes at an early stage. With the help of this monitoring technology, there will be considerable optimization potential in terms of facility availability and effectiveness, which will lead to decisive advantages.
This Predictive Maintenance (PM) method, also known as Condition-Based Monitoring (CBM), is commonly used in machines with rotating parts, such as turbines, fans, pumps, and motors. With the CBM technology, operation status-related information can be recorded in real time. However, this method cannot predict possible failures or wear. By virtue of intelligent sensors and powerful communication networks and computing platforms, models can be created, changes can be detected, and the service life can be calculated in detail.
In order to create a meaningful model, it is necessary to analyze vibration, temperature, current and magnetic field. Through modern wired and wireless communication methods, monitoring of facilities within factories or companies has been allowed. A cloud-based system allows operators and service technicians to easily access information data about machine conditions.
In order to widely use vibration sensors for condition monitoring, two factors are essential; low cost and small size. MEMS-based accelerometers have been increasingly used instead of piezoelectric sensors for higher resolution, excellent drift and sensitivity characteristics, better signal-to-noise ratio, and the ability to detect extremely low frequency vibrations as low as DC range. In addition, they are very power-efficient, thus being an ideal choice for wireless monitoring systems powered by batteries.
Another advantage of MEMS accelerometers compared with piezoelectric sensors is that the whole system can be integrated into one housing System-in-Package (SiP). These SiP solutions are continuously developing by integrating other important functions to form more smart systems, for example, by combining with analog-to-digital converters and microcontrollers with embedded firmware for application-specific preprocessing, communications protocols, and universal interfaces, while also including diverse protective functions.
As the world's leading provider of high-performance signal processing technology solutions, ADI has introduced two high-frequency, low-noise MEMS accelerometers, ADXL1001 and ADXL1002, specifically designed for industrial condition monitoring applications. These MEMS accelerometers can be used to realize high-resolution vibration measurement and provide necessary information for early detection of bearing faults and other common causes of machine faults. The noise performance of the ADXL1001 and ADXL1002 in the high frequency range is comparable to that of the existing piezoelectric sensor technology, so ADI MEMS accelerometers are a highly attractive option as a new condition monitoring product. The ADXL1001 and ADXL1002 can provide high-quality, high-precision data for Smart Factory IoT applications and support smart detection at the edge of the network.
The ADXL1001 and ADXL1002 MEMS accelerometers realize very low noise density over an extended bandwidth with high-g range.. The accelerometers are available in two models, with full-scale ranges of ±100g (ADXL1001) and ±50g (ADXL1002). Typical noise density for the ADXL1002 is 25 μg/√Hz, with a sensitivity of 40mV/g, and 30 μg/√Hz for ADXL1001, with sensitivity 20mV/g. Both accelerometers operate on single voltage supply from 3.0V to 5.25V, and offer useful features such as complete, electrostatic self-test and over range indicator. The ADXL1001/ADXL1002 are available in a 5 mm × 5 mm × 1.85 mm LFCSP package and are rated for operation over a -40°C to +125°C temperature range.
The ADXL1001/ADXL1002 also provide EVAL-ADXL100X evaluation boards to customers, which have 2 sets of spaced vias for populating 6-pin headers, and can be easily attached to prototyping boards or PCB. Small size and board stiffness minimizes impact on user systems and acceleration measurement. The EVAL-ADXL100X evaluation board is specially designed to be mounted on a mechanical vibration table and consists of an ultra-thick PCB which is 0.8 square inch in size. Threaded holes are provided for rigid mounting to a vibration table module. This design allows users to evaluate the full performance range of an ADXL1001 or ADXL1002 vibration sensor without soldering a device to a separate test board. An output terminal is provided with a simple RC low-pass filter with a −3 dB bandwidth of about 20 kHz. This component can be replaced so users can implement a low-pass filter suitable for their own applications on the output terminal of the device.