VT-SSPA1-1-1X/V0/0-24

The VT-SSPA1-1-1X/V0/0-24 is a plug-in proportional amplifier card designed by Bosch Rexroth Indramat for the VT-SSPA Plugin Proportional Amplifiers series. It fits into a standardized Eurocard rack and converts low-level voltage commands into a controlled current that drives a single hydraulic solenoid. By shaping the solenoid current, the module allows industrial controllers to adjust valve spool position smoothly, providing closed-loop regulation of pressure or flow in automated machines.

The amplifier regulates its output around a bias current setpoint of 100 mA, so the valve remains centered when no control signal is present. During dynamic operation, pulse-width modulation is generated at a carrier frequency of 340 Hz, which is high enough to minimize mechanical chatter while keeping switching losses manageable. The command input has an impedance of 20 kΩ, preventing excessive loading of analog signal sources. At full stroke, the driver can deliver a nominal load current of 1.6 A to the coil while operating from its rated bus voltage of 24 VDC. The connected solenoid must have an inductance of at least 15 mH to support the intended magnetic response and avoid excessive current ripple or overheating.

The supply voltage can vary from a minimum of 18 V to a maximum of 35 V, providing operating headroom for battery-backed systems and installations with long cable runs. The conformal-coated printed circuit board carries an IP65 rating when installed behind a sealed front plate, allowing use in washdown environments. A 2 A slow-blow fuse is recommended to isolate the card when a fault causes current to exceed the normal operating range. The connected solenoid has a resistance of 5.5 Ω, and the output connector provides two power pins plus protective earth in a 2 + PE arrangement. Field wiring connects to four screw terminals, providing secure attachment points for the required conductors.