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IM WT1801-01EN
• To display a list of the range settings of all input elements, see “Displaying the Setup Parameter List.” You
can change measurement ranges from the list.
Auto Voltage Range (AUTO (V))
When you press AUTO, the AUTO key illuminates, and the range is set automatically. The measurement range is
switched automatically depending on the amplitude of the input signal as described below. The different ranges
used in the auto range are the same as those available for the fixed range.
Range Increase
The measurement range is increased when any of the following conditions is met.
• The data of measurement function Urms or Irms exceeds 110% of the measurement range.
• The crest factor is set to CF3 and the data of Upk* or Ipk* exceeds 330% of the current measurement range.
• The crest factor is set to CF6 and the data of Upk* or Ipk* exceeds 660% of the current measurement range.
• If all the installed input elements are selected (all the element indicators are illuminated), the measurement
range is increased on all input elements when any of the elements meets the range-increase conditions
described above.
• When a wiring unit is configured, the measurement range is increased on all input elements in the wiring unit
when any of the elements in the unit meets the range-increase conditions described above.
Range Decrease
The measurement range is decreased when all the following conditions are met.
• The data of Urms or Irms is less than or equal to 30% of the measurement range.
• The data of Urms or Irms is less than or equal to 105% of the next lower range.
• The crest factor is set to CF3 and the data of Upk* or Ipk* is less than or equal to 300% of the next lower
range.
• The crest factor is set to CF6 and the data of Upk* or Ipk* is less than or equal to 600% of the next lower
range.
* Even if the NULL feature is on, the values are determined as if it were off.
• If all the installed input elements are selected (all the element indicators are illuminated) and meet the range-
decrease conditions described above, all their measurement ranges are decreased.
• When a wiring unit is configured and all the elements in the unit meet the range-increase conditions described
above, all their measurement ranges are increased.
• If you disable a measurement range in the
settings, that measurement range is
skipped, and the auto range feature operates using only the valid measurement ranges.
• When non-periodic pulse waveforms are applied, the range may not remain constant. If this happens, use
the fixed range setting.
2 Fundamental Measurement Conditions