Guralp Systems CMG-3T - Manual (Page 13)

Operator's guide
you are using one.
7. Connect a 12 Volt power supply, either directly or through the
breakout box or digitizer.
8. Unlock the sensor. If you have a breakout box or hand-held
control unit, you can do this by holding the ENABLE and
UNLOCK buttons on the unit down together for 7 seconds. The
BUSY LED will start flashing, and then go out.
Alternatively, if you are using a DM24 digitizer and Scream!,
right-click on the digitizer's entry in Scream! and select
Control.... Click on the Mass control tab, followed by Unlock. (If
the Mass control tab is unavailable, check the sensor type in the
Sensor type tab, apply, and open a new Control window.)
Alternatively, if you are using a DM24 digitizer and a DCM,
navigate to the Actions Digitizer Setup Port
→ → x page for the
digitizer and click on the Unlock instrument button at the
bottom of the page.
After unlocking the masses, you should be careful not to tilt the
instrument or you may damage it.
9. Check the mass position outputs using a digital multimeter,
digitizer or hand-held control unit.
Re-centre the masses if required. If you have a breakout box or
hand-held control unit, you can do this by holding the ENABLE
and CENTRE buttons on the unit down together for 7 seconds.
The BUSY LED will start flashing, and then go out
Alternatively, if you are using a DM24 digitizer and Scream!,
right-click on the digitizer's entry in Scream! and select
Control.... Click on the Mass control tab, followed by Centre.
Alternatively, if you are using a DM24 digitizer and a DCM,
navigate to the Actions Digitizer Setup Port
→ → x page for the
digitizer and click on the Centre instrument button at the
bottom of the page.
10.Cover the instrument with thermal insulation, for example, a 5
cm expanded polystyrene box. This will shield it from thermal
fluctuations and convection currents in the vault. It also helps
to stratify the air in the seismometer package. Position the
thermal insulation carefully so that it does not touch the sensor
package.
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