Installation and Operating Manual
I/H Converter DSG-BXX113
2019 / 02
J.M. Voith SE & Co. KG │ Division Digital Ventures
Page: 10 / 20
918.3626018884 en
D – 74564 Crailsheim
Version: 3.3
3.2
Operating characteristics
(see fig. 3.1.1)
A set signal w = 4...20 mA generates a magnetic force F
Mag
in the VRM,
the limits of which can be adjusted by means of the X0 and X1
potentiometers and which is then transmitted onto the control piston via
tappet.
The hydraulic force F
Hyd
being proportional to the output signal pressure
P
A
acts against this force.
In the case of the two forces being equal, the control piston is positioned
in the “hydraulic center” as shown in fig. 3.1.1 and the output signal
pressure P
A
corresponds to the set signal. In the “hydraulic center“
position the control piston performs minimum oscillating movements in
the area of the guiding edges P
→
P
A
and P
A
→
T, in order to keep the
output pressure P
A
on the value set by F
Mag
.
When increasing the set signal and thus F
Mag
from this condition, the
control piston position changes and thus connects the output pressure P
A
to the feed pressure P and blocks P
A
towards the tank return line T1and
T2. Now pressure P
A
will increase until the same has returned the control
piston to the “hydraulic center“ and P
A
corresponds to the new set signal.
The spring force F
Fed
of the control spring generates a force-offset in
order to guarantee the I/H converter function for output pressures of
approx. 0 bar, too.
The internal leakage is fed back into tank return line T2.
Function of manual operation knob:
The control magnet of I/H converter is provided with a manual operation
knob, by means of which an adjustable spring force can be set instead of
the magnetic force F
Mag
. This spring force affects the control piston via
magnet armature and tappet. The hydraulic force F
Hyd
, being
proportional to the output signal pressure P
A
also acts against this spring
force here. Thus adjustment of output pressure is possible without
electric connection.
