The AVW211 has the same features and capabilities as the AVW200, with the addition of an internal spread-spectrum radio for wireless communication. The radio operates in the 920- to 928-MHz frequency range, for use in Australia and Israel.
The new AVW200 family of vibrating-wire interface modules applies a new method for measuring the sensors frequency. The traditional method uses a time-domain approach. The natural or resonant frequency at which the wire is oscillating is determined by exciting the wire with an AC excitation, stopping the excitation, and then measuring time between response pulses.
Features
In addition to refining the AC excitation, the new method featured in the AVW200 series takes advantage of a built-in spectrum analyzer that uses spectral interpolation instead of the traditional pulse-timing approach. It samples the returned signal, performs an FFT (fast Fourier transform) to discriminate between spectral components, and then identifies and measures the resonant frequency of the sensor. This means that even in noisy environments the sensor’s resonant frequency can be identified and accurately measured.
Specifications
The new method also provides much better measurement resolution (improving from 0.01 Hz to 0.001 Hz) as well as diagnostic information about the measured frequency. This diagnostic information includes the signal-to-noise ratio, amplitude of the dominant frequency, and an optional spectrum showing all of the frequency components.The AVW211 can be used via SDI-12, RS-232, or PakBus network protocol. Its low power consumption and rugged design match the durability and long-term stability of vibrating-wire sensors. Wireless versions are also available, allowing for remote deployment separate from the datalogger.
