Product Description:

The VT-MRPA1-100 is a plug-in proportional amplifier module produced by Bosch Rexroth Indramat for the VT-VSPA Proportional Amplifiers series. Designed for DIN-rail installation inside control cabinets, the unit conditions analog command signals and drives proportional valves used in flow or pressure regulation tasks across automated machinery. By converting low-level voltage references into controlled solenoid current, the amplifier allows controllers or PLC analog outputs to modulate hydraulic actuator behavior with repeatable accuracy.

The amplifier accepts a supply within its rated operating band and presents a command input impedance of 50 kΩ so that upstream controllers are not heavily loaded. Internal circuitry delivers up to 1.85 A of valve drive current, scaled by an oscillator that switches at 5.6 kHz to minimize inductive ripple in the coil. Normal service relies on a nominal rail of 24 VDC, and protection components on the same PCB block undervoltage and reverse polarity conditions. Environmental shielding is limited to an IP 20 housing, which offers finger-safe openings but no protection against liquid ingress. The module is intended for cabinet installation where the enclosure provides protection from liquids and airborne contamination.

For reliable startup, the control logic engages only after the enable line exceeds 8.5 V and deactivates once it falls below the 6.5 V cutoff, preventing unintentional valve energization during power dips. Overall energy draw stays within 24 VA, a figure useful for sizing cabinet power supplies alongside other modules. The permissible input range spans 18 to 35 V, ensuring headroom above battery-backed sources while tolerating modest drops on long wiring runs. The amplifier snaps onto a TH 35-7.5 rail and connects through 12 screw terminals for straightforward installation and wiring. With a footprint of 40 × 79 × 85.5 mm and a mass of 0.14 kg, it fits easily into dense automation racks.