Bosch Rexorth Valve amplifier Rexroth

General information
The VT-MSFA1 booster amplifier is used to control hydraulic Valves which are to be switched fast. The module is snapped onto a top hat rail. The electrical connection is established via screw terminals. The module is operated with 24 V direct voltage.
By means of the internally generated boost voltage of approx. 48 V which is connected to the valve solenoid during the boost phase and the resulting higher solenoid current (>> INominal) considerably reduced switching times of the valve can be achieved. In holding operation, the solenoid current is reduced. This reduces the actuator operating temperature which again favors a longer life cycle of the actuator.
Power supply unit [1]
The internal power supply unit provides all internally required supply voltages.
Switching inputs [2]
If there is a “low signal” at one of the two switching inputs “IN1” or “IN2” [2], the output stage is blocked irrespectively of the current phase (boost, tightening or holding phase) and the actual current value. Then, there is a fast shut-down of the valve.
When applying a “high signal” to both switching inputs “IN1” and “IN2” [2], the output stage is activated and the valve is switched on.
Voltage and current profile generator [3]
Generates the control signals for the output stage [4].
Current output stage [4]
The power output stage creates the clocked solenoid current for the on/off valve. The output stage output is short-circuit-proof.
Fault recognition [5]
If the valve is connected, the green LED will light up if there is no error. The LED flashes in case of short-circuit or if the solenoid resistance is too high. In case of cable break or internal errors, the LED will go out. The “Ready for operation” output will be taken back with all errors detected. After troubleshooting, there is an automatic restart.
[ ] = Assignment to the block diagram

• Component series 1X
• Analog, Modular design
• For valves: KSDER