Bosch Rexroth VT-MRMA1-1, Руководство по эксплуатации

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About this product 17/52
RE 30214-B/03.2019, VT-MRMA1-1, Bosch Rexroth AG
Table 13: Output stage
Purpose Effect Setting
Generates the clocked control
voltage for the DC motor,
which acts as actuator in the
pressure reducing valve. The DC motor adjusts the pilot
pressure by way of the position
of the spring plate. From this
pilot pressure, the main stage
of the pressure reducing valve
generates the reduced “actual
pressure value” by shifting the
valve spool. None
The output stage output is short-circuit-proof. Moreover, the output stage is
de-energized when no enable is present or a fault has been detected.
Table 14: Enable function
Purpose Effect Setting
Activation of the position
controller and the output
stage. Enables the valve adjustment
or pressure adjustment. Enable signal by machine
control. Indication of enable:
Yellow LED on front panel
Enable input (terminal 7): When a voltage of less than +6 V is applied, the output
stage is blocked independently of the current position command value and actual
position value. The valve remains in the self-locked position. When a voltage greater
than +8.5 V is applied, positioning control and the output stage are activated. An
enable cable break corresponds to a 0 V signal.
When the enable is not set, adjusting the valve is impossible, positioning control
is inactive, but the positioning signal (”position command value reached”) and the
pressure switch are active. The pressure command value therefore also has to be
applied when the enable signal is missing.
▶ Make sure that the enable signal is only given when a new actuating process
of the valve is going to take place. When the new working pressure has been
reached, the enable has to be reset (see also application example in chapter 8.4,
on page 41)!
5.2.5 Actual value preparation
Actual value preparation refers to the closed-loop-controlled actual valve position
value, the resulting actual pressure value and the pressure switch function.
Table 15: Actual valve value acquisition
Purpose Effect Setting
Processing of the actual valve
position value of the position
transducer. Generates the internal actual
position value signal for the
position controller. With zero point potentiometer
Zx
and sensitivity
potentiometer
Gx
.
Zx
: 15 %
Gx
: 90 % to 120 %
The position transducer integrated in the valve is supplied from a voltage output
(terminals 3 and 4). A cable break of a position transducer port is detected (ready
output) and the output stage is switched off.
Output stage (10)
Enable function "external
enable“ (11)
Actual valve position value
acquisition (12)