Guralp Systems CMG-DM24S12AMS - Manual (Page 61)

CMG-DM24S12AMS Operator's guide
3. Connect the voltmeter to pins J and K of the output connector
(corresponding to the low gain vertical component.) Measure the
output of the low gain vertical component. The steady output
voltage should be about zero (± 10 mV).
4. Now turn the sensor on its side, so that the POSITIVE
ACCELERATION arrow points upwards.
5. The low gain vertical component should now read about –5 V,
corresponding to –1g.
If the performance so far has been as expected, the instrument may be
assumed to be in working order and you may proceed to install for trial
recording tests. Most likely, however, you will need to adjust the mass
deflection offset.
Installing the sensor
NOTE: If you are in any doubt about how to install the sensor, you
should contact Güralp Systems.
1. The sensor can be fixed on to any surface either with three M10 or
M12 hexagonal bolt screws and washers (to protect the anodised
surface), or with an appropriate fixing clamp. The three holes
used to fix the sensor are shown in the mechanical drawing of the
sensor base, above. You may find it useful to copy the footprint of
the sensor base onto a metal sheet as a template to drill fixing
holes into the surface where you want to fix the sensor.
2. Fix the sensor to the mounting surface, with the POSITIVE
ACCELERATION arrow pointing in the correct direction. The
accelerometer has no levelling feet, but can use internal simulated
level adjustment to compensate as long as it is fixed to a hard,
clean surface within 1 degree of the horizontal.
The sensitive direction of the sensor is marked on the outside of
the unit, with the arrow pointing towards the positive sensor
output orientation. If this arrow is horizontal, the sensor will be
responsive to horizontal signals; likewise, if the arrow points
upwards, the sensor will respond to vertical ground acceleration
(with positive output corresponding to an upwards ground
movement.)
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