SatisGeo PMG-2, User Manual

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6. MEASUREMENT
The instrument and its accessories are transported in a case. It must be
assembled before an operation.
The measured value of the magnetic field depends very much on the presence of
metal objects near the sensor. The operator should remove all the metal objects prior to
measuring.
6.1. Instrument Setup
Screw together the sensor and the sticks of the post to the desired length
– see
Figure 3.1. The processing unit can be attached to the harness and carried on the chest.
Connect the sensor to the processing unit by using the appropriate connectors. In
the single sensor configuration and AUTO modes, the connecto
r ‘Up sensor’ is used. In
the GRAD sensor mode, both sensors are used. The upper sensor should be connected
to the ‘Up sensor’ connector otherwise the sign of the gradient value is changed.
It is recommended to keep the sensor as far as possible from the processing unit
to limit the influence of the magnetic moment of the instrument.
For the same reason, it is recommended to keep the direction of the advance
along with the profile during the measurement in one area.
6.2. Sensor Orientation
The measured value of the magnetic field does not depend on the sensor
orientation. However,
with the changing orientation of the sensor towards the Earth’s
magnetic field, the signal from the sensor is changed, and the statistical error of the
measurement increases. To achieve the maximum signal the sensor must be oriented in
the north-south direction, so
the ‘north’ mark on the sensor must point to the geographical
north.
6.3. Tuning
Before measuring in a new area, it is necessary to set or check the preliminary
tuning of the instr
ument according to the map of the Earth’s magnetic field, see Figure
5.1. If the measurement is conducted with inaccurately tuned circuits, an error message
is displayed. If the automatic tuning function is on, the tuning will occur automatically
concerning the measured value. The automatic tuning is not performed in the case of an
enormous difference in which the value of the magnetic field is measured with a
significant statistical error. The tuning procedure is described in chapter 5.2.
6.4. Manual Measuring
MANUAL measuring is started by selectin MANUL in the measure menu. The
selection is asserted by [ENTER]. The instrument is prepared to measure in the single
and or gradient sensor configuration. The sensor configuration can be selected in the
setup menu item MODE see chapter 5.4. In the single sensor configuration, the
instrument measures the absolute value of the magnetic field vector. In the gradient
sensor configuration, the device measures the value of the magnetic field in both
locations of the sensors simultaneously. The displayed value of the gradient is
determined by subtracting the value of the magnetic field of the sensor connected to the