Sensor SMT-200 Operation And Technical Manual page 79

SENSOR
Io
--Test results--
No. 1
Temp 20.0 °C
Pol 1
Leak 1401 Mohm
Res 382 ohm
Freq 9.91 Hz
Damp 0.259
Sens 28.7 V/m/s
Dist 0.04 %
Imp *1998 ohm
0 Back to Main
- Repeat Test
Start next Test
5.5 Isolation Table
From the above it will hopefully become clear that external noise and vibration can seriously effect the
test results. To minimise the effect of external noise an isolation table can be constructed. The
geophones can then be placed on this for testing. An example of a simple isolation table is shown
below.
Cases with spikes require holes
to be drilled in the top
Car Inner-Tube
SMT-200 Operations and Technical Manual 2.00/R1
Impedance Failures
Impedance failures could be a result excessive tilt of geophones for the
same reason as distortion failures. Elements that are sticking are likely to
produce a lower impedance reading. If there is not an obvious problem use
the continuous impedance test to further isolate the problem.
Section 5 Geophone Testing
Heavy piece of wood
(Railway Sleeper size)
69