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3 - Description
Soil, Crop and Hybrid Mode
Height sensors use "smart sensor" technology, which take measurements from both the top of the crop canopy and from
the soil surface. This allows the user to select between three modes:
Mode
Height Measure
Soil
The target height is measured from the soil to the sprayer nozzle. Soil Mode is intended for use when there is no crop or light crop cover.
Crop
The target height is measured from the crop canopy to the sprayer nozzle. Crop Mode is intended for use when there is thick crop cover.
Hybrid
Use a combination of the crop and soil readings to improve control. Hybrid Mode is intended for use in all types of crop cover.
Hybrid and Crop mode is usually used when operating in mature cereal grains, row crops or specialty crops. Soil mode is
generally used to follow the ground through young crops, stubble or normal weeds.
• In row-crops, Hybrid mode will work best with the sensor placed directly above a row.
• Some crops will produce a more varying canopy than others. Hybrid mode is recommended for uneven crops.
• When operating in Crop mode when the crop is lodged, or where there is no crop, the sensor will follow the target
down and begin to track the soil. However, when the crop resumes, the sensor may be beneath the crop canopy, or
the canopy might be within the blanking range of the sensor therefore preventing the sensor from making proper
measurements. This situation may require the operator to manually raise the boom as illustrated below.
In this case the Hybrid mode is recommended.
Boom is above crop
Sensing Further Ahead of the Boom
A common misconception is moving the sensor further ahead of the boom will increase performance. Moving the sensor
further ahead of the boom increases the distance between the nozzle and sensor. This puts the sensor at a different location
within the field than the nozzles, which introduces a height error at the nozzles. In severe terrain this height error can bring
the nozzles close to the ground as the sensor reads over the crest of the hill or down a ditch.
Similarly, aiming the sensors ahead (rather than pointing straight down) will reduce sensor performance by providing
inaccurate height readings.
Height Sensor Capabilities and Limitations
• The AutoSlant sensors are designed and built specifically for agricultural purposes.
• The ultrasonic transducer must be clean and dry for optimal performance. The foam disc fitted into the bottom of the
sensor protects the transducer from dust. If the protective foams become wet from rain or drift from the spray nozzles
the sensors may have trouble reading. Furthermore, if the transducer itself becomes wet, leave the AutoSlant system
on, but in manual mode. The transducer's vibrations will clean itself of the water and after a few minutes it will begin
to function again.
• The height sensors will provide height readings from 30 to 300 cm, under typical conditions.
• In order to optimize sensor performance, the AutoSlant sensor has a minimum distance that it will read, also known as
the blanking range. As a result, the AutoSlant sensor is designed to ignore targets closer than 30 cm from the bottom
of the sensor housing.
24
Boom drops where
there is no crop
Sensor is buried in crop
because crop rose
too quickly
Operator manually
lifted boom and
resumed in AUTO
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