Indication interval, measuring interval and span
Possible readings differ from a validated interval of measurement.
Key knowledge
An indication interval is bounded by the extreme possible indications. Its span is the absolute difference between those extremes. A measuring interval is the set of quantity values measurable with a specified instrumental uncertainty under defined conditions. A ±10V indication interval has20V span, but that interval alone does not establish a20V measuring capability. The lower limit of a measuring interval need not equal a detection limit.
Values and equations
span=|q_max−q_min|
- span
- Difference between the extreme indicated values chosen quantity unit
- q_max,q_min
- Extreme possible indications on the stated scale chosen quantity unit
Conditions and scope
- Specify the instrument/configuration, units, bounds and operating conditions.
- Use ordinary difference-based numerical spans on an appropriate interval scale; the formula does not define a span for arbitrary nominal or ordinal codes.
Sources · 3
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
- International Vocabulary of Metrology (VIM3)Joint Committee for Guides in Metrology (JCGM)Reference guideVIM3, entry 4.3VIM3, entry 4.5VIM3, entry 4.7
Evidence and review
Read VIM4.3 indication-interval definition/notes,4.5 interval-span definition and±10V example,4.7 measuring-interval definition/notes. Keep the explicit specified-uncertainty condition and detection-limit distinction.
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- foundation-measurement-interval-span
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- foundations-refresh.1
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