APG IRU-9400 user manual - Manual (Page 22)

IRU Series
Rev. B1 3/10
22
Automation Products Group, Inc.
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Average: Defines the number of target samples (readings) that will be
averaged together to become the distance reading. Each qualified sample (see
Window and Out of Range Samples below) is placed into a first-in, first-out
(FIFO) buffer and averaged with previous samples to generate a steady output.
The higher the number of samples averaged, the greater the smoothing effect of
the readings. A higher Average setting will result in slower response to rapid
changes in the target distance.
Window: Sets the radius of the target acceptance window. The target
acceptance window is a zone extending along the sensing plane in both
directions starting from the target distance. The Window parameter determines
the length that the window extends in each direction. For example, if the
sensor is detecting a target at 5 ft. and the Window is set at 1 ft., then any target
detected between 4 ft. and 6 ft. will be accepted. Any target detected within
the Window will be considered legitimate and figured into the averaging buffer.
Any target detected outside of the Window will considered “out of range” and
will be ignored based on the setting in the Out of Range Samples parameter (see
below).
Out of Range Samples: Determines the number of consecutive target
samples that occur outside of the acceptance window before the “out of range”
target is recognized as a legitimate target. Suppose the Out Of Range Samples
is set to 10. If a target is suddenly detected outside of the acceptance window, it
will be ignored until it has been detected for 10 consecutive samples, at which
point it will be qualified as a legitimate target. If the “out of range” target was
detected for only 9 consecutive samples before moving out of the sensing area,
it would never be acknowledged as a target and the reading would stay with the
last qualified target sample. The combination of the Window and Out of Range
Samples parameters allow the sensors to be used in applications where undesired
targets, such as agitator blades, intermittently enter the sensing area. These filter
parameters are also helpful for qualifying legitimate targets while ignoring errant
echoes that might occur in the application.