Product Description:

The Bosch Rexroth Indramat VT-VSPD-1-21/V0/0-0-1 is a plug-in proportional amplifier card from the VT-VSPA Proportional Amplifiers series. The board conditions command signals and regulates current to directional or pressure proportional solenoids, allowing closed-loop hydraulic actuation within PLC-based machinery. By fitting into a standard Eurocard rack, the unit bridges low-level control voltages and the power demands of industrial valve coils, providing stable and repeatable modulation for automation tasks.

The analog output has a resolution of 1.25 mV, enabling fine incremental steps when the host controller updates the drive command. The board follows the Eurocard footprint of 100 × 160 mm, and all connections are routed through a 64-pole DIN 41612 G backplane header, so wiring is completed without discrete cables. A time-lag fuse rated at 4 A protects the module and field supply rails against overcurrent faults. Command inputs encounter a 100 Ω resistance that helps prevent excessive loading of PLC voltage sources, while the electronics themselves draw up to 1.5 A during peak activity. For actuation, the power stage can deliver 2.5 A to each proportional solenoid, and the connected valve winding must not exceed 19 Ω to guarantee full stroke.

The control loop updates every 2 ms, and large transitions can be smoothed by a programmable ramp that extends to 300 s for gentler motion changes. When the machine is idle, the amplifier settles to a standby draw of 270 mA, and leakage current is held to 0.15% so valve position does not drift during inactivity. The nominal supply of 24 VDC is accepted through the backplane, with continued operation permitted from 21 V to 30 V. An RS-232 serial interface is provided for parameter adjustment and status reading without removing the board.