7ML19981CJ02
MiniRanger Plus – INSTRUCTION MANUAL
Page 27
Sound Velocity
The MiniRanger Plus can be calibrated to compensate for sound velocity error in fixed
temperature, homogenous atmospheres.
The basis is to physically measure the level (measuring tape or sight glass) and enter the
value via P651. The MiniRanger Plus then calculates the sound velocity by comparing the
entered physical measurement to its own ultrasonic measurement.
Blanking
Near blanking (P800) is used to ignore the zone in front of the transducer where
ringdown* or other false echoes (e.g. standing wave, ladder rung) appear as an echo
during the receive cycle. This is usually indicated by an incorrect high level reading and
can be overcome by increasing the near blanking from its factory set value.
Far end blanking is a feature that ignores the zone below the zero or empty level where
false echoes can appear at levels that interfere with the processing of the true echo.
* ringdown is the natural decay of transducer vibration after the transmit pulse ceases.
ringdown or false
echo
true echo (level)
false echo
end of
transmit
0
level
far end blanking
P800 near
blanking
empty distance to transducer
P006
range
typical processing signal
range extension
(P801) as % P006
