Cut-Off Valve Monitoring; Cut-Off Valve Monitoring For Ospe, Ehi-E - Danfoss PVED-CLS User Manual

ENGINEERING TOMORROW
Important
There is no validation in the PVED-CLS that P3074: Cut-off valve CL pull current > P3076: Cut-off valve CL hold
current.
Important
Danfoss recommends not to change the default values for P3074, P3076 and P3097.
Contact your local technical support at Danfoss Power Solutions if there is a need to change these parameters.
Name
Cut-off valve present P3072 U8
Cut-off valve control
P3073 U8
mode
Cut-off valve CL pull
P3074 U16
current
Cut-off valve CL hold
P3076 U16
current
Cut-off valve PWM pre-
P3097 U8
load value
7.1.2

Cut-off valve monitoring

The PVED-CLS continuously monitors the cut-off solenoid valve current level and if it exceeds the defined threshold of
2500mA, the PVED-CLS will de-energize the cut-off solenoid valve and enter safe state.
Furthermore, in off-road mode the PVED-CLS will monitor if the cut-off solenoid valve current level drops below half
of the setting of P3076: Cut-off valve CL hold current. If the cut-off solenoid valve current is found below this level, the
PVED-CLS will de-energize the cut-off solenoid valve and enter safe state.
Whenever switching from on-road mode to off-road mode, the PVED-CLS is performing diagnostics on the cut-off valve,
this is called off-road safety check. If the off-road safety check is not successfully completed, a change to off-road mode
will not be permitted and thus no electro-hydraulic steering will be available. Two different off-road safety checks can be
executed, depending on the valve type.
7.1.2.1

Cut-off valve monitoring for OSPE, EHi-E

This safety check will be executed if P3081: Valve type is set to 0 (OSPE, EHi-E) and a mode change from on-road
mode to off-road mode is requested.
The PVED-CLS checks that the EH-valve main spool can move to a set-point, inside the mechanical deadband, within
the time specified by P3078: Cut-off valve monitoring POST timeout, when it is commanded to do so and the cut-off
solenoid valve is turned on. Then the PVED-CLS checks that the EH-valve main spool cannot move when the cut-off
solenoid valve is turned off, even though the EH-valve main spool is commanded to.
38 | © Danfoss | August 2018
Description of parameter
Cut-off Valve Present/Not Present
-
Valid Values: 0 (NOT PRESENT); 255 (PRESENT)
Cut-off Valve control mode Close loop Control or ON-OFF control
-
Valid Values: 0 (ON-OFF control); 255 (Closed loop control)
mAmp Current required to activate Cut-off valve
mAmp Current required to maintain Cut-off in ON state
% Cut-off valve PWM pre-load value
OEM
OEM
OEM
OEM
OEM
Table 8
Range
0 255 255
0 255 255
100 2000 1100
100 2000 500
0 100 100
AQ00000211
S
S
S
S