Vibrating wire technology is used in many sensors, including strain gages, pressure transducers, piezometers, tiltmeters, crack meters, and load cells. These sensors benefit a wide variety of structural, hydrological, and geotechnical applications because of their stability, accuracy, and durability. While vibrating wire sensors have their benefits, they suffer from one major problem—external noise.
To provide better vibrating wire measurements, Campbell Scientific developed the vibrating wire spectral-analysis technology (VSPECT). This innovative, patented technology delivers the most accurate measurement for vibrating wire sensors. VSPECT observes the incoming sensor signal, performs a Fourier transform and a spectral analysis (transforming the time series into individual sinusoidal components in the frequency spectrum), and determines the sensor frequency by identifying the largest signal in the acceptable range and disregarding noise.
Our first products to include VSPECT were the AVW200-series vibrating wire interfaces, introduced in 2008. These were followed by the CDM-VW300 series of dynamic vibrating wire analyzers, released in 2013, and the CR6 Measurement and Control Datalogger, released in September of this year (see article on page 2). In a few months, the CRVW3 Vibrating Wire Datalogger, our newest VSPECT product, will be released.
The CRVW3 is a small datalogger mounted in an IP66-rated enclosure with either a rechargeable or alkaline battery. Designed exclusively for vibrating wire measurements, the CRVW3 has three channels for directly connecting vibrating wire sensors (no interface required). Optional internal radios will support wireless routing communication.
The CRVW3 is designed to be either an independent datalogger, or a reliable component in a larger data-acquisition system. It arrives field ready and is configured to monitor vibrating wire sensors; no coding by users is needed.
Vibrating wire sensors are an important long-term monitoring tool in structural, transportation, and geotechnical applications, and our VSPECT products make better measurements for these applications. The CRVW3 promises to be a valuable new addition to our VSPECT family.