Calibrating the 3TB
3. Repeat this measurement for several tilt angles.
4. For the vertical sensor, the input acceleration is given by
a
=
g
sin
φ
, whilst
for the horizontal sensor, it is
a = g
( 1 – cos
φ
).
Calculate the input acceleration for each of the tilt angles used, and plot a
graph of mass position output against input acceleration.
5. The gradient of the line obtained gives the sensitivity of the coil (in V/m/s
2
, if
g
was measured in m/s
2
and the mass position in V.)
6. The coil constant
K
is equal to this sensitivity divided by the value of the
displacement feedback resistor, given on the calibration sheet.
58
Issue G - November 2019
