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About this product
Value at test jack position
4, 5
Current ramp time (±20 %)
Pressure command value
attenuator (4)
Linearization of valve
characteristic curve (5)
Amplitude limiter (6)
Valve position controller
Bosch Rexroth AG, VT-MRMA1-1, RE 30214-B/03.2019
The current ramp time can be established according to the following formula from
the voltage of the measuring signals (switch position 4 or 5) at test jack v (front):
1 V
t =
• 1 [sec]
U
t
The following table shows the value measured at the test jack and the associated
current ramp time:
Table 8: Ramp times
U
in Volt 10
5
t
t in sec 0.1
0.2
Table 9: Pressure command value attenuator
Purpose
Limits the maximum actual
pressure value
Example: Application with pressure stage having a nominal value of 100 bar
A voltage applied by the machine control corresponds to 10 V (= 100 %) at input wp.
A max. pressure of 80 bar (= 80 %) is to be possible. Potentiometer Gw is used to
adjust the internal pressure command value to a voltage of 8 V (= 80 %) (voltage at
test jack v with switch position 0). With an applied pressure command value of 10 V,
this corresponds to an actual pressure value of 80 bar.
Table 10: Linearization
Purpose
Compensation of a non-linear
valve characteristic curve
Table 11: Linearization
Purpose
Internal limitation of the valve
position command value
(irrespective of the pressure
command value applied).
5.2.4
Controller and functions closely related to the controller
The description refers to functions that are directly or indirectly related to the
position controller in functional terms.
Table 12: Valve position controller
(7)
Purpose
Generation of output variable
for clocked output stage
from the system deviation of
position.
3
2
1
0.5
0.33
0.5
1
2
Effect
The internal pressure
command value is influenced.
Effect
Generates the valve position
command value from the
pressure command value
Effect
Safety limitation of the valve
stroke to +110 % and -5 %
Effect
Matching of the actual
valve position value with
the internally applied valve
position command value.
0.01
0.05
0.03
0.02
10
20
33.3
50
Setting
G
With potentiometer
to 130 %
Setting
None
Setting
None
Setting
None
0.01
100
: 0 %
W
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