NF FRA51602, Instruction Manual

Page: 161 / 286

5.3 Input settings
5
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5
FRA 51602
5.3 Input settings
5.3.1 Measurement range
The measurement ranges for CH1 and CH2 can be set independently. The setting range is shown below.
Fixed range : 1–3 sequences in the range from 30 mV to 300 V, and 600 V
Auto-range : AUTO
The setting is done using
【
Input
】
–
[MEASURE RANGE]
–
[CH1]
and
[CH2]
.
The nominal values for the range are effective voltage values. The peak input voltage is about 1.4-fold of
range nominal value. Also, regardless of the range, the maximum input voltage drops with frequency. For
more information, refer to " 3.2 Input and output connectors ".
■ Fixed range
Because the range does not change during measurement, discontinuities (steps) in the measurement
values from range changes do not occur. However, if pulse noise or other signals that exceed the range are
included, the data will be unreliable. However, if the range is set too large, measurement error itself will
also increase.
With the fixed range setting, the range is not changed automatically, even if a signal that exceeds the set
range is input (including direct-current or noise, etc.). If the input signal exceeds the range, an over-level
event occurs and measurement data is not obtained (not retained as numerical data).
■ Auto-range
Perform the measurements while monitoring the signal level and setting the range to find the optimum
range. If noise that exceeds the range is detected, expand the range and repeat the measurements. The
reliability of the obtained measurement data is high for the range does not saturate during measurement.
With the auto-range setting, the instrument input circuit will not be damaged if a large signal (up to 600
Vrms) is suddenly input during operation in the high-sensitivity range.
When the signal includes a large amount of noise and a large dynamic range is needed (when the variation
in signal level is large), auto-range should be used. Normally, use the auto-range setting.