Wheel Angle Sensor Calibration - Danfoss PVED-CLS User Manual

ENGINEERING TOMORROW
If dead-bands are too far away from neutral, jerky steering at small flow can be observed, and further in will lead to
unwanted periods of no EH flow output.
Important
Danfoss recommend to perform calibration under the following circumstances:

Oil temperature during calibration routine should be at normal operating condition.

Steered wheels characteristics (air pressure, dimension) needs to be according to the normal operation conditions.

The OEM needs to ensure that the wheel angle sensors mechanical installation is fixed in such a way that there is no
mechanical backlash, e.g. full fixation and alignment of WAS.

Load on vehicle is allowed during calibration, but it needs to be assured that maximum steering pressure during
calibration routine is <80% of Relief valve setting (e.g., Relief valve setting of 200bar, max steering pressure during
calibration: 160bar).

The operator needs to assure that the steering valve is supplied by sufficient oil flow during the calibration routine.

Before any calibration routine is started, it has to be assured that all air has been bled from the steering system. This can
be obtained by turning the steering wheel fully left, fully right minimum 10 times. Thereafter no abnormal noise or
vibration should occur when steering.

Any calibration should be performed on an on-road surface (i.e. unpainted concrete or asphalt). Danfoss recommends
not to perform calibration on ice-surface, off-road-surface (mud, dirt etc.) or a painted, sticky surface. The tractor should
not be lifted from the ground during calibration.

The WAS shall be calibrated prior to spool calibration
Important
Danfoss recommends to test and qualify the valve auto-calibration parameters for any vehicle series.
Attention
bystanders are aware of the upcomming calibration routine and the moving wheels.
9.1

WHEEL ANGLE SENSOR CALIBRATION

As per default, a PVED-CLS will boot up in WAS calibration service mode. From here the operator can chose to use the
WAS auto-calibration routine from the Danfoss PLUS+1 SERVICE TOOL or perform a manual WAS calibration (see 16.5)
General guidelines:
•
WAS on CAN = 1000 counts full scale from full left to full right. Noise less than 3% full scale
WAS analogue = Minimum 3V bandwidth full left to full right. Noise less than 3% full scale.
•
The wheel angle sensor output should remain inside the range from 0.5VDC to 4.5VDC to keep clear of short
circuit detection thresholds.
•
Danfoss recommends that the manual calibration of any wheel angle sensors is done with the PVED-CLS in
WAS calibration
•
For applications other than auto guidance, WAS resolution from 20 to 45 deg/volt will provide adequate
results
Furthermore; at every startup, the PVED-CLS validates the wheel angle calibration sectors (analogue and CAN), so;
P3185 < P3189 < P3187 or P3185 > P3189 > P3187; if this validation fails, PVED-CLS will enter Wheel Angle Sensor
calibration , but only if WAS type is set to CAN (i.e. P3244 set to 1).
For the Analogue Wheel Angle
sector 16.3.4) this means that:
16.3.5) this means that: