BARTINGTON INSTRUMENTS
Page 6 of 20 OM2448/4
When Unbalanced is selected, one input of each differential amplifier is connected to Signal
Ground, which is normally joined to Power Ground at the sensor, thereby eliminating the error
caused by voltage dropped in the long Power Ground cable.
When Balanced is selected, both inputs of the differential amplifier are connected to the sensor.
In Balanced mode, the differential signals and input amplifiers give the best possible accuracy.
There is no interaction of signal ground currents and unequal sensor ground potentials caused
by different voltage drops in the Power Ground cabling. Compared to Unbalanced mode, this
configuration has the higher interference noise rejection, as noise will appear as a common
mode signal at the input amplifiers.
After filtering, each analogue signal is fed to the appropriate BNC connector via a low impedance
buffer. These buffers allow long cables to be used with high input impedance data acquisition
systems. Refer to product brochure DS2520 for maximum loads.
Note:
Measuring these outputs can lead to a greater accuracy than that displayed on the
LCDs.
4.2.3. Filtering
A permanent low-pass filter and selectable high-pass filter are provided for each channel: X, Y
and Z. Refer to product brochure DS2520 for the cut-off frequency of the filters.
The low-pass filters remove the high frequency noise components of the signal from the sensor.
The high frequency signal is associated with the excitation signal (breakthrough) of the fluxgate
sensor.
The high-pass filters are intended to filter out the DC or static field component so that the
alternating components above the cut-off frequency of the filter can be isolated.
5. Magmeter-2 Inputs, Outputs and Controls
Note:
The precise external layout of the Magmeter-2 and Magmeter-2 may differ subtly
but the principles remain the same. Outline drawings for both units are available from the
product page.
