Guralp Systems CMG-3TB - Manual (Page 32)

CMG-3TB
Procedure
To install a sensor at the bottom of a borehole of known depth using
sand backfilling:
1. Measure or calculate the physical volume of the unit which is to
be installed in the borehole. (The volume of a cylinder v =
πr
2
h.) Also measure the internal diameter of the borehole.
2. Measure and pour in a sufficient quantity of sand to fill the
borehole to a depth of around 300mm.
3. Connect the signal cable to the connector on top of the sensor.
Ensure that the “O”-rings inside the housing are clean, and
tighten the knurled connector nut to its end stop.
4. Fix the main lifting cable to the shackle on top of the strain
relief mechanism, and run the signal cable through the
mechanism using the built-in clamps (without tightening them.)
Do not allow the signal cable to bear any of the sensor's weight.
32 Issue C