Product Description:

The VT-VSPA2-50-10/T5 proportional amplifier card is produced by Bosch Rexroth Indramat within the VT-VSPA Proportional Amplifiers series. It conditions command and feedback signals for proportional hydraulic valves, allowing PLCs and analog controllers to drive spool position with repeatable accuracy. By converting low-level reference voltages into controlled coil currents, the card forms the interface between electrical automation hardware and fluid-power actuators used for pressure, flow, and position regulation in machinery.

Its monitoring loop includes an actual-value output calibrated to ±2.5 V ±2%, giving external controllers a scaled representation of valve position. The current input channel presents a load of 100 Ω, so a 20 mA source develops the full 2 V span without distortion. Command entries taken through the differential input see an impedance of more than 50 kΩ, minimizing loading on delicate analog sources. A field-replaceable fuse rated at 2 A protects the circuit from supply shorts, and an internal reference generator supplies ±10 V ±2% for potentiometer or joystick setpoints. Normal operation requires a stabilized supply of 24 VDC, enabling direct connection to common machine control power buses.

When driving a proportional valve coil, the output stage can deliver up to 2.5 A, allowing the board to handle medium-sized hydraulic operators without an external booster. For manual trimming, the potentiometer input offers an impedance of more than 100 kΩ, while the dedicated ramp terminal has an input impedance of 10 kΩ, matching most PLC voltage cards. The integrated ramp generator counts through five discrete settings so slew rates can be matched to cylinder dynamics. Undervoltage is avoided by the 18 VDC lower limit, and the design tolerates transients up to the 35 VDC upper limit, permitting reliable service on unregulated industrial supplies.