Road Switch - Danfoss PVED-CLS User Manual

ENGINEERING TOMORROW
If the consecutive number of test passed never reaches the value specified by P3100, the test will continue endlessly, or
until either the safe state is triggered as mentioned above or on-road mode is requested.
If the fall time is observed longer than specified by P3101: Safety-checks IMD – Maximum fall time, the COV solenoid
will be concluded as stuck open and the PVED-CLS will enter safe state. There is no limit on how long the rise time can
be.
This check ensures that the cut-off valve can achieve the blocked state, when the cut-off solenoid valve is de-energized.
By moving the EH-valve main spool in the mechanical deadband, it is ensured that no oil flow is send to the steering
cylinders.
Name
Safety-checks IMD -
P3098 U8
Rise time limit
Safety-checks IMD -
P3099 U8
Fall time limit
Safety-checks IMD -
P3100 U8
Pass criteria
Safety-checks IMD -
P3101 U16
Maximum fall time
Attention
IMD Safety check typically completes in 1.5 to 3 sec within the recommended viscosity operating range 12 to 75mm2/sec
(Refer EHi TI). In number of cases, IMD Safety check may continue for extended period of time. Below are few instances:
1. Engine OFF: No hydraulic pressure available.
2. Very Cold Oil / High Viscosity Oil: Viscosity higher than 460 mm2/sec. (Refer EHi TI).
3. Cold Oil (75 to 460 mm2/sec) : IMD safety check may take longer than 3 sec.
4. Cut off solenoid coil: The coil may drop off the EHi Valve and stays attached to the connector.
5. Contamination: One or more spools could be blocked.
6. Active Steering: The operator continues steering wheel use during IMD safety check.
7.2

ROAD SWITCH

A road switch sub-system can be used to force the PVED-CLS and OSPE/EHi-E, PVED-CLS and EHi-H or PVED-CLS
and EHPS valves into a state which is suitable for on-road operation while keeping the PVED-CLS operational. This state
is called "safe on-road" state. PVED-CLS displays the Road-Switch status in the operation state message by the flag
"Lock-out status for EH-steering functionality" – please refer to PVED-CLS communication protocol, for more details.
The PVED-CLS can remain powered in the safe on-road state. The OEM is responsible for building architecture suitable
for achieving the correct SIL/PL/AgPL-level for shutting off the EH-steering flow for public road transportation.
Important
40 | © Danfoss | August 2018
Description of parameter
Maximum rise time after switching ON cut-off valve for indicating EH-
x10mSec
Spool is under control during safety-check.
Maximum fall time after switching OFF cut-off valve for indicating EH-
x10mSec Spool is under control during safety-check.
P3100 specifies how many safety-check cycles with successful EH-Spool
- control shall be executed before PVED-CLS passes the safety-checks.
If the EH-Spool does not return to neutral within this timeout, the cut-off
x10mSec
solenoid is concluded to be stuck open
Range
OEM 10 100
OEM 10 100
OEM 2 8
OEM 100 1000
AQ00000211
30 S
25 S
2 S
100