TeeJet 844-AB Sprayer Control - Manual (Page 11)

9
98-70007-EN R4
844-AB
Speed sensor calibration
The speed sensor must be calibrated in order to provide the proper
speed and area readings. The value is determined by the number
of impulses generated by the speed sensor in 100 metres, or by
manually entering the number.
NOTE: During speed calibration, the 844-AB will automatically sense
whether a Wheel speed or Radar speed sensor is being
used.
Proximity/magnetic impulses
Figure 28: Proximity/magnet impulses
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Automatic calibration
To automatically calibrate the speed sensor, mark a distance
of exactly 100 metres. Press the Plus and Minus keys
simultaneously to clear the contents of the display and activate
auto calibration mode. “CAL” will be displayed on the lower right
of the screen.
Figure 29: Speed sensor automatic calibration
CAL
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Drive toward the initial point of the of designated 100 metres.
At the starting location, press the Plus key once to begin the
calibration process. Continue driving the course. The 844-AB
will count the impulses as the sprayer moves. The speed at
which the vehicle travels is not important. As the ending point is
reached, press the Plus key again. The console will display
the speed calibration number.
NOTES: The auto speed calibration process should take place in a
field-like environment with the sprayer tank at least half full.
It is recommended to repeat the automatic speed calibration
process at least twice and use an average of the speed
calibration numbers.
Figure 30: Speed sensor automatic calibration
CAL
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NOTE: Once the automatic speed calibration process has been
activated, no other functions will operate until the console
receives speed impulses for calibration. To deactivate
automatic calibration mode, press the Plus key twice.
During the automatic calibration process, the 844-AB will
automatically sense whether a proximity/magnetic or radar ground
speed sensor is installed. If a manual entry is preferred, refer to
Manual calculation.
Manual calculation
To manually calculate the proper value for Wheel speed sensor
impulses, the circumference of the wheel to which the sensor is
mounted must be known. It can be measured by marking the tire
and measuring the distance covered as the mark makes one full
revolution. Once the number is known, use the following formula:
The result can be entered instead of using the automatic calibration
method. Use the Plus or Minus keys to adjust the value. Press
the Programme key to save the value and advance to the next
programme step.
Radar speed impulses
Figure 31: Radar speed sensor
250 rAd
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