Product Description:

The VT-VSPA1K-2-1X-V0-A4 is a plug-in proportional amplifier card from Bosch Rexroth Indramat and belongs to the VT-VSPA Proportional Amplifiers series. The module conditions voltage or current command signals and converts them into controlled solenoid current for directional or pressure valves used in hydraulic automation systems. Its Euro-card format allows direct insertion into a standardized 32-pin rack, and onboard electronics maintain a linear relationship between the electrical reference and hydraulic output. By placing the amplifier close to the valve drive, wiring is simplified and electromagnetic interference is reduced.

The card occupies a 100 x 160 mm footprint and weighs 0.15 kg, so it fits a single DIN 41494 slot without adding significant mass. A logic carrier running at 250 Hz establishes the dither frequency that helps prevent spool stiction. Operation is centered on a 24 VDC rail, and the board is fused so its own draw never exceeds 2 A. Command flexibility is provided through a differential input that accepts up to +10 V as well as a 4 mA to 20 mA current loop, letting the amplifier accept both voltage references and two-wire transmitter signals. Internal conditioning circuitry maintains signal integrity between these ranges and the regulated power domain.

For actuation, the power stage supplies up to 1.9 A, matching typical solenoid windings used in proportional pressure or flow control. Overall board demand peaks at 24 VA, so cabinet thermal design must account for the resulting dissipation. The DC bus may climb to 35 V during regenerative events, yet it must remain above 18 V to keep the control logic active. A precision regulator also provides an internal reference with 25 mA of sourcing capability, enabling external potentiometers or feedback sensors to complete the closed-loop circuit without additional signal conditioners.