Description
The Bosch Rexroth RKP-PQI (Part Number: 0811405159 / 0 811 405 159, also designated under the type code VT-VPRAP 1-540-10/V0/SI) is an electronic p/Q (Pressure and Flow) Control Card / Amplifier Board. It is designed to control variable displacement Radial Piston Pumps (RKP) manufactured by Bosch Rexroth.
Installed in a Eurocard rack or valve amplifier housing, the card processes pressure feedback and swashplate displacement signals to maintain precise dynamic control of both hydraulic flow (Q) and operating pressure (p) in heavy-duty industrial hydraulic power units.
Key Specifications & Identification
| Attribute | Details |
| Manufacturer | Bosch Rexroth / Robert Bosch Industrial |
| Model / Series | RKP-PQI (Radial Piston Pump p/Q Controller) |
| Part / Material Number | 0811405159 / 0 811 405 159 |
| Type Code | VT-VPRAP 1-540-10/V0/SI |
| Primary Application | Electro-hydraulic stroke & pressure control for Rexroth RKP pumps |
| Control Functions | Closed-loop Swashplate Position (Flow Q) & System Pressure (p) Control |
| Feedback Signals | Swashplate LVDT position sensor and 0–10V / 4–20mA pressure transducer inputs |
| Form Factor | Standard Eurocard printed circuit board assembly for rack / card-cage mounting |
Primary System Functions
- Dual Closed-Loop Control (p/Q Switching): Simultaneously processes flow (swashplate stroke) setpoints and pressure limit commands, automatically executing smooth override transitions between flow-controlled and pressure-limiting modes.
- Proportional Valve / Actuator Drive: Amplifies internal control commands into high-response current outputs to drive the electro-hydraulic proportional pilot valve attached to the RKP pump housing.
- LVDT Transducer Demodulation: Supplies excitation voltage and demodulates feedback signals from the onboard swashplate position encoder (LVDT) to monitor pump stroke in real time.
- System Safeguards & Monitoring: Features onboard cable break detection for pressure/position sensors, supply voltage monitoring, and fault output logic to shut down or bypass the pump in the event of transducer failure.
Servicing & Installation Guidelines
- Hydraulic Pressure Release: High-pressure hydraulic lines can retain dangerous energy even when power is off. De-energize the pump motor, depressurize accumulator circuits, and lock out system controls (LOTO) before inspecting control connections.
- ESD & Handling Precautions: Onboard op-amps, analog logic circuits, and signal conditioning ICs are sensitive to electrostatic discharge. Always wear a grounded anti-static wrist strap when handling or replacing the module.
- Potentiometer & Jumper Verification: Before placing a replacement card into service, verify that onboard potentiometer settings (e.g., zero adjustment, gain ramps, sensor calibration) and jumper configurations match the original machine baseline setup.
- Shielding & Signal Grounding: Always use shielded twisted-pair cabling for analog setpoints and transducer feedback lines to avoid electromagnetic interference (EMI) from variable frequency drives (VFDs) or motor power cables.
