APG IRU-9400 user manual - Manual (Page 23)

Rev. B1, 3/10 IRU Series
23
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Sample Rate: Sets how many times per second the sensor takes a reading.
The Sample Rate is expressed in Hertz. Options allow rates from 1 to 50 Hz.
The maximum Sample Rate setting is determined by the Max Distance setting.
The greater the Maximum Distance setting, the slower the maximum allowable
Sample Rate setting. A higher Sample Rate will achieve a more rapid response
to target movements but can also decrease the stability of the measurement.
Lowering the Sample Rate will help increase sensor life and decrease the chance
of detecting errant echoes. It is highly recommended that the Sample Rate be
set only as high as is necessary for the application. A sample rate of 1-2 Hz is
usually appropriate for slow moving level sensing applications.
Multiplier: Used to true the sensor’s distance reading with the actual physical
measurement to the target. Since the speed of sound is not constant through
all environments and temperatures, the multiplier parameter allows the user
to adjust for these variations in atmosphere. To determine the appropriate
multiplier setting, measure from the face of the sensor to the intended target.
Then divide the measured distance by the distance reading of the sensor, and
enter the resulting value in the Multiplier setting. For example, if the target is
measured at 2.5 ft. from the sensors face, and the software distance reading is
2.61 ft. The multiplier setting would be 2.5 / 2.61, which = 0.9579
Offset: Used to adjust the zero reference point of the sensor. When the Offset
is set to 0, the zero reference of the sensor is at the face of the transducer.
Setting the Offset to a negative number will move the zero reference backward
(behind the sensor face), while a positive setting will move the reference
forward (in front of the sensor face).
Temp_Comp: Used to enable or disable the internal temperature
compensation of the sensor. The speed of sound through air changes about
0.18% for every 1 0 C of temperature change. Enabling the internal temperature
compensation can reduce the effects of temperature changes by 50% or more,
depending on the temperature gradient through the sensing range.