Product Description:

The VT-VSPA1-2-1X-V0-A4 amplifier card is produced by Bosch Rexroth Indramat and belongs to the VT-VSPA Proportional Amplifiers series. It is a plug-in controller that converts low-level command voltages into regulated coil currents for proportional valves used in hydraulic positioning and pressure loops. By fitting on a standardized Euro-card and interfacing with rack-mounted power supplies, the module allows machine builders to tune spool movement electronically rather than rely on fixed orifice hardware. This arrangement helps the valve respond more consistently to changing command signals during normal machine operation.

The board footprint is 100 x 160 mm, a Euro format that slides into DIN 41494 subracks. A 48-pin form F edge connector routes power, command, and feedback to the cabinet harness. Nominal rails are 24 V DC, filtered to support the internal oscillator running at 250 Hz; this clock sets the pulse-width-modulated drive to the valve coil. The output stage can source up to 1.9 A for the proportional solenoid. Differential inputs exceed 50 kΩ, and the potentiometer line is above 100 kΩ, so signal sources are not heavily loaded. A regulated +10 V reference at 25 mA powers trims, and the current input path uses a 100 Ω burden resistor for sensor loops.

System protection is provided by a 2 A miniature fuse that disconnects the supply if the coil or wiring is shorted. The electronics tolerate input buses from 18 V up to 35 V, so the card remains active despite startup dips or overvoltage conditions. Four discrete command call-ups can be selected on the front DIP switch, enabling preset flow or pressure profiles to be recalled without re-adjusting the analog trims. The ramp generator input offers more than 10 kΩ of resistance, permitting long acceleration times without overloading the upstream controller. With a mass of only 0.15 kg, the amplifier adds little weight to densely packed valve control racks.