Product Description:

The VT 2000S4X-2 is a plug-in proportional amplifier card manufactured by Bosch Rexroth Indramat for the VT 2000 Proportional Amplifiers series. Mounted in a valve control rack, it translates low-level command signals into regulated solenoid current so hydraulic actuators track setpoints accurately. By doing so, the card functions as an interface between the machine controller and the proportional valve, maintaining consistent pressure or flow in industrial automation systems.

Electrical operation is based on an input supply of 24 VDC, although the circuitry tolerates excursions down to 22 V and up to 35 V. The front-panel command socket accepts a maximum of +6 V against a fixed 1 kΩ internal resistance, while the second input channel is isolated by a 100 kΩ network to reduce loading on external electronics. Feedback is simplified because the actual current test point delivers 1 mV/mA, allowing quick calibration with a standard voltmeter. Internally, the amplifier provides a ±9 V stabilized reference for its signal paths and limits solenoid excitation to 800 mA during peak demand, while a separate limiter keeps bias current below 300 mA to prevent accidental valve shift. The control loop measures and trims coil current in real time so magnetic force remains proportional to the operator command.

Field wiring is handled through a 32-pin male DIN 41612 D connector, and protection against overcurrent is supplied by a panel-mounted 2.5 A T fuse. When energized, the module draws less than 1 A from the power bus and its total power uptake stays below less than 25 VA, minimizing heat inside the enclosure. The regulated output stage can source or sink ±25 mA, which is adequate for driving most feedback transmitters tied to the same hydraulic loop. A nominal solenoid resistance of 19.5 Ω pairs with this current capability to help maintain stable coil temperature, while total load current ripple is held within ±25 mA for smooth valve movement.