Guralp Systems CMG-5T - Manual (Page 6)

CMG-5T
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The central hole for the main fixing bolt; and
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The serial number. If you need to request the sensor production
history, you will need to quote either the serial number of the
sensor or the works order number, which is also provided on
the calibration sheet.
2.2 Initial testing
To test the 5T before installation, you will need a power source which
can deliver 100 mA at 10 to 36 V and a digital voltmeter (DVM) with 1
and 10 V ranges. Also ensure that the supplied cable is connected with
the correct polarity (see the Appendices).
To make it easier to measure the output from the sensor, you can use a
hand-held Control Unit or a custom interface box, which can be
manufactured from a screw clamp connector block. This will simplify
the connections to the appropriate connector pin outputs.
1. Place the 5T sensor on a flat, horizontal surface.
2. Connect the power supply, observing the correct polarity for
the cable supplied, and switch on.
3. Connect the voltmeter to pins L and M 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. Repeat the measurement for the N/S and E/W low-gain
component outputs (pins C/D and K/U respectively).
5. Now gently turn the sensor onto its side, propping it carefully
to prevent rolling.
6. The low gain vertical component should now read about –5 V,
corresponding to –1g.
7. Roll the instrument until the N/S line is vertical, with N at the
top.
8. The low gain N/S component should now read +5 V,
corresponding to +1g.
9. Roll the instrument until the N/S line is horizontal.
10. The low gain E/W component should now read +5 V.
6 Issue E