Product Description:

The Bosch Rexroth Indramat VT-VSPA2-1-21/VO/T5 is a proportional amplifier card in the VT-VSPA Proportional Amplifiers series. Mounted in a rack next to a machine controller, it converts low-level command voltages into regulated solenoid currents so that hydraulic proportional valves follow the demanded spool position. By placing this card between PLC analog outputs and valve coils, the system can regulate flow or pressure precisely without a separate power stage, making the unit a standard interface element in molding presses, metal-forming lines, and material-handling assemblies.

Within the rack, the amplifier occupies a 100 × 160 mm Eurocard and connects through a 48-pin DIN 41612 Form F header to the backplane. The power section uses a nominal 24 VDC supply that is fused at 2 A and can deliver up to 2.5 A of output-stage current to the valve coil. Five analog reference channels accept ±10 V, and the first can also be routed from the card’s ±10 V internal command source to simplify bench setup. Input accuracy is stabilized by a 100 Ω current load, while digital enable switches on at 8.5 V and off at 6.5 V to prevent chatter. A ramp generator with a time count of 5 shapes the rising and falling edges of the current so the valve moves smoothly under changing load conditions, and voltage feedback is trimmed through a ±30% zero-adjust range to reduce residual offsets at startup.

Feedback to the control system is provided through a ±2.5 V actual-value output that mirrors real coil current. The ramp input has a resistance of 10 kΩ, allowing external potentiometers or PLC outputs to adjust slew rate without overloading their drivers. The card operates within supply limits of 18 V to 35 V, and outside this range the output stage is disabled to help protect the driver circuitry during supply disturbances.