Product Description:

The VT 2000 S 20 is a plug-in proportional amplifier card produced by Bosch Rexroth Indramat for the VT 2000 Proportional Amplifiers series. Installed in a valve control rack, it converts low-level command voltages into regulated coil current so that hydraulic directional or pressure valves follow the desired setpoint. By combining reference generation, current feedback, and fuse protection on one board, the card provides a compact interface between a machine’s PLC and its proportional solenoids.

The board follows the Eurocard format with a footprint of 100 x 160 mm and a front panel height of 128.4 mm, allowing direct insertion into standard 19-inch subracks. All electrical terminations use a 32-pin male, DIN 41612 D connector, which simplifies connection to a compatible rack backplane. Nominal power is supplied by a single 24 VDC source, and an internal transconductance stage scales the command input at 1 mV per mA to produce the required valve current. This arrangement allows the card to reach the rated setpoint while maintaining a regulated load current of ±25 mA for feedback circuits and keeping overall power draw below 25 VA.

Operating limits protect upstream supplies and downstream coils. The solenoid channel can source up to 800 mA, while a slow-blow fuse rated at 2.5 A T isolates the card during overloads. Acceptable bus voltage ranges from 22 V to a ceiling of 35 V; beyond this point, overvoltage protection disables the output stages. Internal reference rails are held at ±9 V to support stable command processing when line levels fluctuate, and current consumption remains below 1 A. Coil resistance of 19.5 Ω at 20 °C and a 100 kΩ second-input impedance match common valve dynamics, while total mass is only 0.1 kg, which minimizes load on card guides and fan-tray airflow.