F.W. Bell 7030, Инструкция по эксплуатации

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F.W. BELL Model 7030 Gauss/Tesla Meter Instruction Manual
Section 6 – Flux Density Measurement 6-19
ANALOG
OUTPUTS
Each channel provides a corrected and uncorrected analog output voltage
signal available from standard BNC connectors. The uncorrected output
signal is representative of the magnetic flux density as measured by the Hall
probe. The corrected output signal is compensated for influences of
temperature and frequency, as well as non-linearities inherent in the Hall
probe and instrument. The corrected output is specified with a higher
accuracy than the uncorrected output, with a bandwidth up to 250 Hz. The
uncorrected output is less accurate, but has a bandwidth up to 50kHz. A
separate BNC connector, labeled “Vector Summation”, provides a corrected
output signal that is proportional to the resultant magnitude of the three
channels’ vector sum. The vector summation output has a bandwidth of
10Hz.
Standard full scale output ranges are 3V
RAW
, 10V
RAW
, 3V
RMS
, and 10V
RMS.
Adjustable full scale ranges up to 9.9 V
RAW
or 9.9V
RMS,
in increments of 0.1V,
are also available. The raw output settings provide voltage signals that are
replicas of the magnetic flux density waveforms being measured. The rms
settings provide dc voltage signals that are proportional to the rms value of
the ac component of a flux density signal. These outputs may be connected
to a voltmeter, oscilloscope, recorder, or external analog-to-digital converter.
Note: With dc mode operation and rms output settings, only the ac
component of the flux density is represented at the analog outputs.
See Section 2 – Specifications , for bandwidth and accuracy of the analog
outputs.
Flux Density Range and Output Voltage Range
Full scale of the present flux density range always corresponds to the full
scale setting for the analog output voltage range. For example, if the full
scale flux density range is 30 gauss and the full scale analog output voltage
range is 3 volts; then a reading of 30 gauss will produce a voltage of 3 volts at
the output. A reading of -20 gauss will produce a voltage of -2 volts at the
output.
Using Analog Outputs with Autorange
When using autorange and the analog output features together, the following
situation can occur. Suppose the present range is 3 kG and the present
reading is +2.8 kG. The analog output will be +2.8 Vdc. The signal then
increases to +3.2 kG, which would force an automatic change to the 30 kG
range setting. The analog output will now be +0.32 Vdc because of the range
change. This can lead to problems if the analog signal is being used to make
decisions, because there is no indication that a range change has occurred.
In these situations it is best to select a fixed range that covers the expected
flux density span.