Prosonic M - FOUNDATION Fieldbus Technical Data
Endress+Hauser 79
10.1.5 Performance characteristics
Reaction time The reaction time depends on the parameter settings. The minimum values are:
• FMU40/41/42/43: min. 2 s
• FMU44: min. 3 s
Reference operating
conditions
• Temperature = +20 °C (+68 °F)
• Pressure = 1013 mbar abs. (15 psi abs.)
• Humidity = 50 %
• Ideal reflective surface (e.g. calm, smooth fluid surface)
• No interference reflections within signal beam
• Set application parameters:
– Tank shape = flat ceiling
– Medium property = liquid
– process conditions = calm surface
Measured value resolution
Measuring error Typical specifications for reference operating conditions (include linearity, repeatability, and
hysteresis):
1
whichever is greater
Influence of the vapor pressure The vapor pressure at 20 °C (68 °F) gives a hint on the accuracy of the ultrasonic level
measurement. If the vapor pressure at 20 °C (68 °F) is below 50 mbar (1 psi), ultrasonic level
measurement is possible with a very high accuracy. This is valid for water, aqueous solutions, water-
solid-solutions, dilute acids (hydrochloric acid, sulfuric acid, ...), dilute bases (caustic soda, ...), oils,
greases, slurries, pastes, ...
High vapor pressures or outgassing media (ethanol, acetone, ammonia, ...) can influence the
accuracy. If conditions like these are present, please contact the Endress+Hauser support.
Sensor Measured value resolution
FMU40 1 mm (0.04 in)
FMU41 1 mm (0.04 in)
FMU42 2 mm (0.08 in)
FMU43 2 mm (0.08 in)
FMU44 2 mm (0.08 in)
Sensor Measuring error
FMU40 ± 2mm (0.08 in) or 0.2% of set measuring distance (empty calibration)
1
FMU41 ± 2 mm (0.08 in) or 0,2% of set measuring distance (empty calibration)
1
FMU42 ± 4 mm (0.16 in) or 0,2% of set measuring distance (empty calibration)
1
FMU43 ± 4 mm (0.16 in) or 0,2% of set measuring distance (empty calibration)
1
FMU44 ± 4 mm (0.16 in) or 0,2% of set measuring distance (empty calibration)
1