Guralp Systems Scream - Manual (Page 24)

Scream! 4.5
Sensor Sensor type code
Units
(V/A)
CMG-3T, 360 s – 50 Hz response CMG-3_360S_50HZ V
CMG-3TB or 3V / 3ESP borehole,
30 s – 50 Hz response
CMG-3B_30S_50HZ V
CMG-3TB or 3V / 3ESP borehole,
100 s – 50 Hz response
CMG-3B_100S_50HZ V
CMG-3TB or 3V / 3ESP borehole,
120 s – 50 Hz response
CMG-3B_120S_50HZ V
CMG-3TB or 3V / 3ESP borehole,
360 s – 50 Hz response
CMG-3B_360S_50HZ V
CMG-3TB or 3V / 3ESP borehole,
360 s – 100 Hz response
CMG-3B_360S_100HZ V
Some English descriptions are also accepted, e.g. “120s
velocity”, “100Hz acceleration” but this is not a free-format,
parsed field.
•
To set the sensitivity (or gain) of the sensor components,
include the line
G=vertical-sensitivity,N/S-sensitivity,E/W-sensitivity
These values are given on the sensor calibration sheet. For
velocity sensors, they are given in units of V m
-1 s (V/ms -1 ). The
gain of an accelerometer is expressed in V m -1 s 2 (V/ms -2 ).
Because Güralp Systems sensors and digitisers use differential
inputs and outputs, the sensitivity is quoted as
2 × (single-ended sensitivity) on the calibration sheet.
•
To set the coil constants of the sensor components, include the
line
COILCONST=vertical-constant,N/S-constant,E/W-constant
These values are given on the sensor calibration sheet.
•
To set the local acceleration due to gravity, include the line
GRAVITY=acceleration
You should give this value in ms -2 , if you know it. If you miss
out this line, Scream! will use a standard average g value of
9.80665 ms -2 .
24 Issue K