Ag Leader GeoSteer Operation Manual - Manual (Page 72)

Auto Calibrate
58 GeoSteer System
Valve Deadband
Oil flow is proportional to voltage or pulse width signal changes sent from the GeoSteer Control Unit. It takes a certain
minimum amount of signal to start oil flow through the valve. If the signal is below that minimum amount no oil flows and the
steering axle will not move. The range of voltages or pulse widths where there is no valve movement is called the Deadband.
The Deadband is detected by incrementally increasing the signal sent to the valve in both directions until the GeoSteer Control
Unit detects motion from the Wheel Angle Sensor.
Figure 2-56 Deadband Calibration
To start the Valve Deadband calibration, drive the vehicle in a straight line between 2.0 and 5.0 mph (3.2 and 8.0 k/h). Press
the Resume button to start the calibration process. The vehicle will continue to drive in a straight line for a time. Eventually the
steering axle will begin to move to both sides. Once this happens the system will have determined the deadband for the valve
and move on to the next step.
Angle Sensor
The GeoSteer Control Unit reads the value of the Angle Sensor to determine the position of the steering mechanism. During
the calibration process, the GeoSteer Control Unit holds the Angle Sensor at a constant angle at different positions from full
left to full right and measures what the change of heading is at each position. The change of heading is calculated using the
GPS antenna. At the conclusion of the calibration the GeoSteer Control Unit can determine the expected change of heading for
any Angle Sensor position. It is also able to determine the exact Angle Sensor reading that should steer the vehicle in a straight
line, even if the Angle Sensor is not installed with the steering angles to the left and right not equal.
Figure 2-57 Angle Sensor Calibration
Note: For the next step in the calibration process, the vehicle will turn full left and full right. Make sure all objects are clear of
the area where calibration is taking place.