First encounters
3.3.3 The inclinometer monitor unit
All 3TB borehole sensor systems can operate successfully in boreholes with tilt
angles of up to 3.5° from the vertical although instruments which can operate at tilts
of up to 12° are available – please contact Güralp Systems for details. To check that
the instrument is installed suitably close to the vertical, a two-axis inclinometer is
installed within the sensor housing. The inclinometer monitor unit is used as a
visual guide to the sensor's tilt only, and should not be used if precise attitude
information is required.
Caution:
You should check the inclination of the instrument before
unlocking the sensor masses, since too great a tilt can damage the
components.
To measure the attitude of a 3TB instrument:
1. Connect the inclinometer monitor unit to the
CONTROL
connector of the
breakout box.
2. Switch the
ON/OFF
switch on the monitor unit to the
ON
position. The
inclinometer is powered separately from other parts of the system; this
switch provides power to the downhole circuitry as well as to the monitor
unit. The inclinometer should not normally be powered up whilst the sensor
is in use.
3. Read off the
X
and
Y
components of the tilt from the analogue meters.
4. If both tilts are within the green shaded region, the instrument is close
enough to vertical that it can be levelled and centred successfully. If either
output is in the red shaded region, you should
not
attempt to unlock or centre
16
Issue G - November 2019
