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

CMG-3T
velocity output. There is also a RANGE switch allowing you to alter the
sensitivity of the meter.
Calibration
The hand-held control unit can be used to calibrate the 3T. To activate
the calibration relays, turn the knob to the component you wish to
calibrate, and introduce a calibration signal on the CAL SIG banana
sockets.
Control commands
You can use the hand-held control unit to centre, lock and unlock the
sensor masses.
•
To unlock the sensor masses, press the ENABLE switch down,
and the LOCK/UNLOCK switch up simultaneously. The BUSY
LED will light. All three masses are unlocked, each in turn. The
sensor then automatically moves on to centre the masses, during
which time the BUSY LED will flash. When the BUSY LED goes
out, the instrument is ready for use.
You should not attempt to move the instrument without re-
locking the masses.
•
To lock the sensor masses, press the ENABLE and
LOCK/UNLOCK switches down simultaneously. When the BUSY
LED goes out, the instrument is ready for transportation.
•
To re-centre the sensor masses, press the ENABLE and CENTRE
switches down simultaneously. When the BUSY LED stops
flashing, the centring process has finished. You may need to
initiate several rounds of centring before the instrument is
ready. When no more centring is required, pressing the
ENABLE and CENTRE buttons has no effect.
Note: The ENABLE, LOCK, CENTRE and UNLOCK switches require
only a single quick press to initiate the processes. Do not hold them
down.
For more details on the control system, see Section 5.2, page 36.
Outputs
The remaining banana sockets provide easy access to the output
voltages of the instrument. For each component (vertical, N/S and
E/W):
32 Issue N