Product Description:

Bosch Rexroth Indramat manufactures the VT 2000-S-4X-R5, a plug-in proportional amplifier card in the VT 2000 Proportional Amplifiers series. The board converts low-level command voltages into a controlled solenoid current that drives hydraulic proportional valves. By closing the loop between electrical reference signals and fluid power, it permits programmable logic controllers to adjust actuator position, speed, or pressure with repeatable accuracy. The unit installs inside standard Eurocard racks, allowing quick replacement during retrofits or service work on automated presses, molding machines, or material-handling lines.

Its internal supply rail is designed for a nominal input of 24 VDC, and the circuit accepts sources from 22 V to 35 V while keeping the logic reference at ±9 V with a 1% tolerance to stabilize comparator stages. A pulse-width modulator running at 200 Hz shapes the output so valve inductance sees a constant average current. Drive electronics consume up to 25 VA, which helps size the required power supply and cabinet heat dissipation. The adjustable bias network can preload the valve with as much as 300 mA, allowing spring-force offset and deadband reduction without modifying the main command channel.

A programmable ramp generator stretches rising or falling edges over 5 s, preventing hydraulic shock when setpoints change suddenly. Field safety is supported by a miniature glass fuse rated at 2.5 A T; its time-lag characteristic withstands inrush yet isolates faults. When the valve reaches full stroke, the amplifier can deliver a peak solenoid current of 800 mA; combined with a coil resistance of 19.5 Ω, this limits copper heating and supports steady-state force. Additional terminals provide 6 V command and 800 mV actual sockets plus a 100 kΩ high-impedance input so external meters can monitor performance without loading the control loop.