Product Description:

The VT 2000-50 is a plug-in proportional amplifier card produced by Bosch Rexroth Indramat for the VT 2000 Proportional Amplifiers series. Installed in a control rack, the card converts low-level command voltages into regulated solenoid currents that position hydraulic valve spools, allowing precise pressure or flow control in automated machinery. By separating signal conditioning from the power stage, the module supports setup of presses, molding machines, and other servo-hydraulic axes that require stable current loops rather than direct drive from a PLC analog output.

The board follows the Eurocard format at 100 x 160 mm, and it mates with a 32-pin male DIN 41612 Form D connector for backplane power and signals. When energized, the card draws up to 1 A maximum, with total power intake limited to 25 VA maximum. Protection against sustained overload is furnished by a 2.5 A T slow-blow fuse. The diagnostic current socket is calibrated at 1 mV to 1 mA, allowing loop output to be measured without breaking the circuit. Input 2 presents 100 kΩ impedance for auxiliary setpoints, and the regulator can source or sink ±25 mA for external monitoring equipment.

Signal conditioning is organized around the command socket, which accepts a full-scale reference of 6 V across a load of 1 kΩ. Internal analog rails are stabilized at ±9 V, helping the modulation stage remain stable despite line variation. The power amplifier delivers up to 800 mA to the valve solenoid, while the separate bias circuit is limited to 300 mA so the neutral position can be trimmed without saturating the coil. Separate bias control also helps center the valve spool during adjustment and supports stable response near null. Accurate current regulation accommodates the winding's 19.5 Ω resistance at 20 °C for repeatable hydraulic control.