Product Description:

The VT-SSPA1-100-13/V0/0-24 plug-in proportional amplifier is produced by Bosch Rexroth Indramat for the VT-SSPA Plug-in Proportional Amplifiers series. The card mounts in a valve electronics rack and generates pulse-width-modulated current to drive proportional solenoid actuators in hydraulic control loops. It converts a voltage reference from a PLC into controlled coil current, allowing hydraulic pressure or flow to track an analog command. This operating method supports controlled motion and force in molding presses, test stands, and material-handling equipment. The rack-mounted format also places the amplifier near related valve control electronics while keeping the hydraulic power components separate from the signal-processing stage.

The electronics operate from a nominal supply of 24 V DC, with a permissible lower limit of 18 V and an upper limit of 35 V. This range allows the board to share a common control supply with other machine electronics without requiring a dedicated regulated source. At its maximum setting, the board delivers up to 1.7 A of solenoid current, while the factory preset is 1.2 A for standard valve coils. A bias circuit provides an adjustable offset from 0 mA to 250 mA for accurate spool centering. The command channel accepts a 0–10 V reference and has an input resistance of 20 kΩ, reducing the electrical load placed on the command source. Output operation begins only after the supply exceeds the 12 V switching threshold. Connected coils must have an inductance of at least 15 mH to maintain stable current behavior under pulse-width modulation.

For dynamic solenoid control, the amplifier modulates the magnetic field at 150 Hz, which smooths electromagnetic force and limits heat buildup in the connected coil. The enclosure, when fitted with its designated cable gland, can operate at ambient temperatures as low as -25 °C and as high as +70 °C. This broad operating range supports installation on mobile machinery and near industrial process equipment where surrounding temperatures can vary considerably. The enclosure carries IP65 ingress protection, preventing dust entry and resisting low-pressure water jets or fluid spray. Its sealing supports placement near hydraulic equipment and in washdown areas when the assembly is installed correctly. The adjustable bias circuit permits precise null adjustment, while the current modulation method helps the valve spool respond smoothly to changes in the analog command.