Step Pulse Calibration Example - Reftek 151D User Manual

Rev A
8.2.2 Step Calibration Example
The expected seismometer output for a step calibration input signal can be
calculated with the following formula:
Voutput_max = Cal_Sensitivity * Sensitivity * (A_input) * T * 0.0725
Where:
Cal_Sensitivity
Sensitivity
A_input
T
If you have a step voltage input with amplitude = 1.5 Volts, the expected
maximum peak output voltage of the seismometer with nominal Cal
Sensitivity and Output Voltage Sensitivity would be:
Vp_output = 10 * 2000*(1.5 / 47500) *120*0.0725
Vp_output = Volts (Nominal)
5.49
Note: Values 10 (Cal Sensitivity) and 2000 (Output Voltage Sensitivity)
should be taken from the 151D Seismometer Data Sheet
The 180 Wrangler recorder can be used to generate a step signal for
confirmation. This can be accomplished in the WebUI through the
Parameters>Sensor Calibration Signal menu. Select signal enable
checkbox for the relevant channels and a duration of 599s, amplitude of 1.5V
and signal type of Step. Select a Step Duration of 300s and an Interval of
600s. Press Send to confirm these parameters (note this does not send the
signal).
Reftek Systems Inc.
REF TEK 151D Broadband Seismometer Users Guide
151D-UG
Calibration Sensitivity from the supplied 151D Data
Sheet (nominally 10 m/s^2/A)
Output Voltage Sensitivity from the supplied 151D Data
Sheet (nominally 2000 V/(m/s)).
Calibration voltage input amplitude / Resistance of the
calibration coil in ohms (Calibration coil resistance is
nominally 47.5 kΩ)
Sensor Period (120s)
12/4/2023
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