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KINEMETRICS SS-1 RANGER SENSOR


CALIBRATION

1 Natural frequency

2 Measure damping without external resistor

Using frequency generator, apply square wave 0-6 V, 0.04 Hz = 25 s period to calibration coil thrugh 100 ohm resistor.

Oscilloscope har 1 Mohm input resistance so we can say we measure seismometer output coil without external resistance.

Figure below shows screenshot from oscilloscope. Lower trace is calibration coul pulse (before 100 ohm resistor). Upper trace is signal coil output.

Kinemetrics SS-1 Ranger sensor step response, no ext damping
Kinemetrics SS-1 Ranger sensor step response, no ext damping
X1 = 356 mV
X2 = 264 mV
X3 = 196 mV

First calculating overshoot ratio:

X2/X1 = 264/356 = 0.742
X3/X2 = 196/264 = 0.742

Then reading damping from table 1 in Model SS-1 "Operating Instructions":

Overshoot ratio 0.74 => Damping hm when resistance RX of external circuit is infinity: 0.09541

3 Measure damping with RX = 5000 ohm

Kinemetrics SS-1 Ranger sensor step response, 5000 ohm ext damping
Kinemetrics SS-1 Ranger sensor step response, 5000 ohm ext damping
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Page last modified on November 21, 2016, at 10:51 AM
Electronics workshop
Department of Earth Science - University of Bergen
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