Product Description:

The VT-VSPA2-50-11/T1 is a plug-in proportional amplifier card produced by Bosch Rexroth Indramat as part of the VT-VSPA Proportional Amplifiers series. Installed in a hydraulic control rack, it converts low-level command signals into accurately metered coil current for proportional solenoid valves. This function allows machine PLCs to impose repeatable force or flow profiles in industrial automation tasks such as pressing, molding, and material handling.

The module runs from a nominal supply of 24 VDC; internal regulation and a bias current of 50 mA ±25% keep the output stage centered when no command is present. A clock frequency of 220 Hz modulates the power transistors, providing fine current resolution while avoiding audible noise in the valve. The input stage presents a load of 100 Ω on current-mode control lines, so upstream cards are not overburdened. The maximum solenoid drive is 1.5 A, enabling the card to operate medium-frame proportional valves, while total card consumption stays below 1.2 A. Four voltage inputs accept ±9 V references, a fifth accepts ±6 V, and a sixth channel combines 100 kΩ impedance with a ±10 V span for position feedback or trim. A ramp-time count of 1 identifies the internal slope generator that smooths rapid setpoint changes.

Protection features include a 2.5 AT fuse on the supply rail and an enable circuit that activates only when the control line exceeds 8.5 V. The undervoltage and overvoltage limits are fixed at 22 V and 35 V, protecting both field wiring and onboard components. The output regulator maintains the reference rails at ±9 V, ensuring consistent scaling for the connected sensors and command sources. Input scaling, bias control, and the regulated output allow the card to maintain stable valve positioning under fluctuating plant power conditions.