Glossary · Sensors and measurement
Measuring range
Also known as: Measuring interval, Instrument range
German: Messbereich
In metrology, the measuring range (measuring interval) of an instrument is the set of values of quantities of the same kind that it can measure with specified instrumental uncertainty under defined conditions, bounded by a lower and an upper range value.
- Sensors
- Standards
In one sentence
The measuring range of an instrument is the interval of values it can measure within its specified error limits under defined conditions.
Example
A pressure transmitter has sensor limits of 0 to 40 bar, but its measuring range is set to 0 to 16 bar for a hydraulic circuit.
How it applies
- Engineering: Many transmitters have fixed sensor limits and an adjustable set range between lower and upper range values. Accuracy specifications are often given relative to the set range or to the upper sensor limit, which changes the effective error when the range is turned down.
- Commissioning: The configured range must match the scaling in the controller. A mismatch produces plausible but wrong values.
- Operation: Values outside the measuring range are not reliable. Many transmitters signal over- or underrange, for example with defined current values per NAMUR NE 43.
- Documentation: Record the set range with each instrument, and state overload limits separately; the overload limit is not part of the measuring range.
Measuring range vs. measurement range (application)
The measuring range is a property of the instrument. The Measurement range (application) is what the process requires; it has to lie within the measuring range.