
6/44 4WRLD | Directional control valve
BoschRexrothAG, RE29289, edition: 2023-05
Function
Symbol V and V1-
The control spool of the main valve is not in asafe
position after the release is switched off. The enable
acknowledgment (pin 3) is not set.
If the supply voltage fails or in case of cable break,
the integrated electronics will de-energize the control
solenoid, the pilot control spool will move to the fail-safe
position and will unload the pilot oil chambers of the
main valve. Operated by the spring, the main valve
control spool will move to the offset position
(approx.6% P→B/A→T).
Symbol E., W. and Q3-
If the control spool of the main valve is in the covered
spring-centered central position, the enable
acknowledgment (pin 3) is set. If the control spool of the
main valve leaves the covered spring-centered central
position or the release is set, the enable acknowledgment
expires.
If the supply voltage fails or in case of cable break,
the integrated electronics will de-energize the control
solenoid, the pilot control spool will move to the fail-safe
position and will unload the pilot oil chambers of the
main valve. The main valve control spool assumes the
covered, spring-centered central position.
Safety function
Thanks to the control solenoids (enable pin3, low signal)
at the connector (XH2), shut-off is enabled.
The control spool of the valve is in spring-centered
central position after shut-off (see notes).
Enable acknowledgment pin 8 for solenoid B is "high".
When the control solenoid is connected (enable pin 3,
high signal), the valve can be regulated in both directions
by command value presetting.
Enable acknowledgment pin 8 for solenoid B is "low".
The integrated control electronics (OBE) of the valve
enables the additional shut-off of achannel according to
EN13849-1in both directions (depending on the symbol,
the valve can be considered as safely shut-off). For this
purpose, asuitable control system must be provided to
perform the plausibility check between the
direction-dependent valve signals "enable input" and
"enable acknowledgment" (diagnosis signal fed back by
the valve) and to react in anerror case. When using
symbolV, the valve cannot be used in asafety-relevant
manner according to EN13849-1.
Monitoring
The digital control electronics enable comprehensive
monitoring functions/error detection including:
▶ Undervoltage
▶ Communication error
▶ Cable break for analog sensor inputs and digital
position measurement system
▶ Short-circuit monitoring for analog/digital outputs
▶ Monitoring of the microcontroller(watchdog)
▶ Temperature of the integrated electronics
IndraWorks DS PC program
To implement the project planning task and to
parameterize the IAC-Multi-Ethernet valves, the user may
use the IndraWorks DS engineering tool
(seeaccessories):
▶ Project planning
▶ Parameterization
▶ Commissioning
▶ Diagnosis
▶ Comfortable administration of all data on aPC
▶ PC operating systems: Windows XP (SP3),
Windows 7-10
Notice:
▶ SymbolV and V1-:
Pilot-operated 4/3 directional control valves are
only functional in the active control loop and do
not have alocking basic position when deactivated.
Consequently, "external check valves" are required
in many applications and must be taken into
account regarding the switch-on/switch-off order.
While the electrical supply voltage is being
switched off, the drive may be accelerated for
ashort time in functional directionP → B.
▶ Symbol E. and W.:
Pilot-operated 4/3 directional control valves with
positive overlap are functional in controlled or
regulated axes. The overlap in the de-energized
state is approx.20% of the control spool stroke.
While the release is being switched off, the drive
may be accelerated for ashort time in functional
directionP →B. (For further details, please refer
to operating instructions 29391-B)
▶ 4/3 directional control valves do not have
aleakage-free basic locking when deactivated.
Leakage must be considered when designing
the drive.
▶ Valve type 4WRLD can be used as shut-off element
of cat. 3 or 4 (up to PLe according to EN13849-1).
For both categories, anadditional shut-off element
is required to achieve atwo-channel shut-off.
For further information on the safety application,
see operating instructions29391-B.