Lakeshore 425 - Narrow Band Mode; Wide Band Mode; Autorange and Range Selection

34 cHAPTER 4: Operation
Model 425 Gaussmeter
4.5.2.1 Narrow Band Mode
The narrow band mode has been designed to measure AC fields ranging from 10 Hz to
400 Hz. The monitor output will provide an AC voltage proportional to the measured
AC field, where ±3.5 V equals ±full scale for the selected range.
4.5.2.2 Wide Band Mode
The wide band mode has been designed to measure fields of higher frequencies,
expanding the instrument’s capability to measure AC fields ranging from 50 Hz to
10 kHz. The monitor output will provide an unfiltered AC voltage proportional to the
measured AC field, where ±3.5 V equals ±full scale for the selected range.
4.5.3 Autorange and
Range Selection
The Model 425 is equipped with an autoranging feature that will automatically
select the appropriate field range for the measured field. In some cases it may be
desirable to manually select the field range. Autorange is not recommended when
measuring AC fields with a large DC background field. Autorange and manual range
selection are available by pressing Range.
Menu navigation:
RangeQ Range (refer to TABLE 4-4)
Default: range 4 (highest)
Interface command: RANGE, AUTO
FIGURE 4-3 Narrow band mode frequency response plot
FIGURE 4-4 Wide band mode frequency response plot
1
Error (%)
Frequency (Hz)
10 100 400 1000
-60
-50
-40
-30
-20
-10
10
0
-0.7%
-2.3%
Frequency (Hz)
10 10050 1000 10000
Error (%)
-0.2%
-0.4%
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0