CDM-VW300/305 Dynamic Vibrating Wire Analyser

The CDM-VW300 is a 2-channel interface between vibrating wire sensors and dataloggers that allows shorter intervals between measurements. This allows the same sensors used for static monitoring to also be used for sub-second dynamic monitoring.

The analyser greatly reduces noise that often occurs with the use of vibrating-wire sensors. It allows the signal to carry through longer cables, giving flexibility in sensor and datalogger siting. The analyzer allows high data rates, and multiple CDM-VW300 modules can be connected to one datalogger. The CDM-VW305 is similar to this item, but has 8 channels.

The CDM-VW300/305 also simplifies post-processing of data by computing common values internally. Vibrating-wire data is reported as measured frequency or as the frequency squared with a multiplier and offset applied. The thermistor data is reported as resistance or is converted to degrees Celsius using the thermistor's Steinhart-Hart coefficients. The CDM-VW300 also can internally compile rainflow histograms of the final data, and report the values at user-specified intervals with a high degree of configurability in the histogram format.


  • Scan Rates: 20, 50, 100 Hz
  • CPI Baud Rate: selectable from 25 kbps to 1 Mbps
  • Input Resistance: 5 kΩ
  • Measurement Frequency Accuracy: ±(0.005% of reading + Resolution)
  • Measurement Resolution (typical values for a 2.5 kHz resonant gage):
Rate (Hz)
Noise Level
(Hz RMS)
 1  0.001
 20  0.008
 50  0.015
 100  0.035


  • Gage Resonant Frequency Range:
          Sample Rate (Hz) Minimum Gage Frequency (Hz) Maximum Gage Frequency (Hz)
20 290 6000
50 290 6000
100 580 6000


  • Thermistor Accuracy: 0.15% of reading (thermistor accuracy and resistance of the wire should be considered as additional errors)
  • Thermistor Measurement Rate: 1 Hz


Datalogger Compatability

The CDM-AVW300/305 can be used with the CR800, CR1000 or CR3000. It requires the addition of the SC-CPI module with these loggers.



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Campbell Scientific Peripherals

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