BARTINGTON INSTRUMENTS
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b. When the sensor output is digitized, it may be necessary to include an analogue, low-pass
anti-alias filter to prevent the creation of in-band noise by mixing the 12.8kHz excitation
frequency with the sampling clock frequency of the digitizer.
The level of unwanted breakthrough at 12.8kHz has been minimized in the Mag585 and
Mag592 but may still cause an apparently raised noise level when sampled at low sampling
frequencies without further analogue filtering.
c. In applications such as surveillance and magnetic signature monitoring it may be required
to remove both the DC standing field and all AC noise and pick-up above a set frequency. The
band of interest will be, say, 0.01 to 10Hz and a band pass filter can be used to provide the
required signal.
The Magmeter and PSU1 power supply units, which can be used with all sensors, contain
three low pass filters with a -3dB point at 10kHz together with three high pass filters with a
-3dB point at 0.1Hz.
The SCU1 signal conditioning unit provides filters with independent control of the low and
high pass filter sections, together with offset and gain control for the output of each axis.
6.5. Magnetic hysteresis
The Mag585 and Mag592 are designed to have an extremely low magnetic hysteresis. However,
Bartington Instruments recommends your magnetometer is not subjected to magnetic fields
greater than its stated measuring range for extended periods as this could alter the DC offset. If
this occurs, the offset will exhibit drift as it returns to its original offset specification.
Caution:
Subjecting the magnetometer to fields in excess of 2 x the nominal range may
cause inaccuracy in future measurements. Degaussing the magnetometer can reverse
such an effect.
6.6. Environmental precautions
Refer to the product brochure for maximum environmental electrical and mechanical ratings.
Caution:
Exceeding the maximum ratings may cause irreparable damage to your sensor.
7. Troubleshooting
The Mag585 and Mag592 are unlikely to suffer any defects in normal use. The most likely causes
of failure, and their solutions, are detailed in the following table:
