Campbell Scientific AVW200-series Vibrating Wire Interfaces - Manual (Page 65)

Appendix A. Conversion from Hertz
The calibration report provided with each vibrating wire sensor contains the
information required to convert Hertz, the frequency value output by the
AVW200, to the appropriate units (e.g., displacement pressure).
These steps convert Hertz to the appropriate unit (e.g., displacement, pressure):
1. If the values in the Calibration Report are in digits, use the following
equation to convert the AVW200’s frequency values from Hertz to digits.
Digits = (Hz/1000) 2 x 1000
2. Use the gage factors and polynomial provided in the Calibration Report to
calculate displacement.
A.1 Displacement Example
FIGURE A-1 provides a calibration report for a displacement transducer. The
following steps convert Hertz (the value output by the AVW200) to
displacement.
1. Convert Hertz to digits:
Digits = (Freq/1000) 2 *1000
2. displacement = (3.598e-9)*Digits 2 + (1.202e-3)*Digits + (-3.1682)
Therefore,
if Freq = 2400 then:
Digits = (2400/1000) 2 x 1000 = 5760
displacement = (3.598e-9) * (5760) 2 + (1.202e-3) * 5760 + (-3.1682)
= 3.875 inches
A-1