Hydraulic And Peripherals Config; Cut-Off Valve; Principle - Danfoss PVED-CLS User Manual

ENGINEERING TOMORROW

Hydraulic and peripherals Config

7.1.1

Cut-off valve

The cut-off valve is an essential part of an OSPE/EHI and an integral part of many of the safety functions in the PVED-
CLS.
The integrated cut-off valve (COV) will block the L and R steering flows to the steering cylinder when de-energized.
The COV is piloted by the COV solenoid valve which is opened by applying power to the cut-off coil.
The COV spool has a dual function; in blocked state, it blocks L and R steering flow as well as hydraulic pilot pressure
supply to the solenoid valve bridge (SVB).
For more details, please see the Danfoss document, PVED-CLS Safety Manual.
7.1.1.1

Principle

This PVED-CLS monitors the current being delivered to the cut-off valve and applies the selected current control
algorithm.
In closed loop mode, the current is kept constant regardless the battery voltage what makes it possible to use the
same solenoids in all systems/machines.
If the monitored current exceeds the defined threshold of 2.500mA, the cut-off valve de-energizes and PVED-CLS
enters the safe state.
Furthermore, the cut-off solenoid valve connection test is executed when in the Safe on-road steering state and the
safe state is triggered if the cut-off solenoid valve is found to be connected.
In off-road mode, the current is also monitored and if it drops below half of the setting of P3076 (Cut-off valve CL hold
current), the PVED-CLS will enter safe state too.