Safety Considerations
The steering architecture shall be designed with care. Controlling an EHPS or EH valve with a PVED-CL is
designed for off-road use only. More single channels of control may be identified in the architecture,
meaning that a single failure may have an impact on the steering behavior which cannot be resolved by
the architecture itself.
In these situations the driver or external equipment must intervene to bring the steering system to a safe
state.
The PVED-CL has on-board fault monitoring on the sensor interface as well as other critical parts of the
system. Please refer to
on page 101 for an overview of the PVED-CL fault
monitoring.
On-road Operation
W
Warning
The PVED-CL shall be de-energized while driving on-road. It is the OEMs responsibility to establish the
necessary means to inform and de-energize the PVED-CL from the cabin when driving on public roads.
Vehicle Speed Sensor
The vehicle speed sensor may be used to modulate the steering valves output as a function of vehicle
speed. However, the PVED-CL has no means to validate the validity of the vehicle speed signal as long as
the messages arrive correctly and the data field is within the valid range. Therefore:
W
Warning
It is the OEMs responsibility to establish a reliable vehicle speed signal to the PVED-CL.
The provider of the vehicle speed signal shall implement means to detect faults and let the vehicle speed
sensor go silent if a fault is detected. A silent vehicle speed sensor will be detected by the PVED-CL and it
will enter fault state or optionally reduced state.
Closed-loop Operation
The PVED-CL may be used in closed-loop applications such as auto-guidance or row guidance. The PVED-
CL has no means to validate the validity of an input steered wheel angle set-point or steered wheel
position as long as the set-point conform to the timing and data range requirements. Therefore:
W
Warning
It is the OEMs responsibility to establish a reliable steered wheel angle set-point to the PVED-CL.
Analogue Input Sensors (Joystick or Wheel Angle Sensor)
The PVED-CL has no means to validate the validity of an input if the voltage conforms to range
requirements.
Any undetected faults may be resolved by changing to steering wheel steering.
W
Warning
It is the OEMs responsibility to establish reliable analogue signal connections to the PVED-CL.
Operation Manual
PVED-CL Controller for Electro-Hydraulic Steering, Version 1.38
Safety Considerations
14 |
©
Danfoss | May 2016
11025583 | AQ00000216en-US0302
