Operator's guide
•
The
SENSOR POWER
connector is a 10-way mil-spec plug, which
should be connected to a source of 12 – 30 V DC power, for
supplying to the borehole instrumentation.
•
The
HOLELOCK POWER
connector is a 10-way mil-spec plug,
which should be connected to the Holelock Control Unit whilst
the hole lock is being manipulated. Because of the high voltages
employed, the hole lock circuitry is entirely isolated from the rest
of the electrical systems in the sensor and surface unit; it is not
usual to power the sensor whilst using the hole lock.
The borehole control unit is supplied with a 3 m cable as standard. This
can be extended up to 100 m without compromising signal quality. The
sensor uses amplifers with high common mode rejection to ensure the
signal to noise ratio is maintained over this distance. Individually
shielded twisted-pair cabling
must
be used for the sensor outputs,
control lines and power supply. If you need to make up a suitable cable,
you should confrm the cable type with Güralp Systems.
The push-buion switches which operate the sensor's control commands
(mass locking, unlocking, and centring) are housed beneath waterproof
lids. You must release the fxing screws holding the lids down before
you can initiate any commands.
December 2004
13
