Danfoss PVE Series 4 Technical Information page 14

Technical Information
Functionality
14
PVE, Series 4 for PVG 32/100/120 and PVHC
The PVE features Closed Loop Control (CLC). This is made possible by on board electronics and an
integrated feedback transducer that measures spool movement. The integrated electronics compensate
for flow forces on the spool, internal leakage, changes in oil viscosity, pilot pressure, etc. This results in
lower hysteresis and better resolution.
In principle the set-point determines the level of pilot pressure which moves the main spool. The position
of the main spool is sensed in the LVDT which generates an electric feed-back signal registered by the
electronics. The variation between the set-point signal and feed-back signal actuates the solenoid valves.
The solenoid valves are actuated so that hydraulic pilot pressure drives the main spool into the correct
position.
The LVDT (Linear Variable Differential Transducer) is an inductive transducer with very high
resolution. When the LVDT is moved by the main spool a voltage is induced proportional to the spool
position. The use of LVDT gives contact-free connection between mechanics and electronics. This means
an extra long lifetime and no limitation as regards the type of hydraulic fluid used.
The PVEO and PVHC do not have embedded control electronics and do not support closed loop control.
520L0553 • Rev GD • Jan 2014