タイトルまたは説明

The sensor of the meter pulses in the direction of the product surface. There, they are reflected back and received by the sensor. The meter measures the time t between pulse transmission and reception. The meter uses the time t (and the velocity of sound c) to calculate the distance D between the sensor membrane and the product surface: d = c •t/2. As the device knows the installation height H from a user entry, it can calculate the level as follows: L = H D . 
B: blacking distance
D: distance value
L: level value
H: installation height
F: full span value
L=H-D
An integrated temperature sensor compensates for changes in the velocity of sound caused by temperature changes. Calibration Enter the empty distance H and the span F to calibrate the device. 

Blanking distance: Span F may not extend into the blanking distance B.  Level echo from the blanking distance cannot be evaluated due to the transient characteristics of the sensor.