APG DCU-1100 user manual - Manual (Page 23)

Rev. A2, 11/06 DCU-1104 and DCU-1108
23
Automation Products Group, Inc.
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Lift Station Example
A 20 ft. deep lift station requires that a pump turn ON when a level is closer
than 4 ft. to the DCU-11. The pump must stay on until the level drops to 18 ft.
from the DCU-11. An alarm relay is to be energized under normal operation
and should open for failure in power, communication, invalid readings, high
level above 3 ft. from sensor, or loss of echo.
Setting the
averaging in
Mode 6 at 10 to
20 samples will
give a good stable
reading. In most
tank level
applications, we
can have high
averaging (Mode
6) and slow
sample rate times
(Mode 5) because
the levels change
slowly. To
calculate the time
required to completely fill the averaging buffer, take the sample rate times the
number of samples averaged. For example, if the sample rate is 5.00 seconds
and the averaging is 10, it would take 50 seconds to fill the buffer resulting in a
50 second average.
The Out-of-Range samples (Mode 7) are the number of successive samples
outside of the window specified in Mode 8 that the sensor will ignore. After
this number of successive samples have been discarded the ones following will
be sent to the averaging buffer. This allows the sensor to ignore objects that
move into the area between the sensor and the target for short periods of time.
To figure the time period that the sensor will ignore these objects before
locking onto them, take the sample rate (Mode 5) times the number of Out-of-
Range samples (Mode 7). An example of where this would be used would be
an- agitator in a tank. Every time the agitator goes around it passes directly