Description
🔹 Product Overview
The Bosch Rexroth VT-VRPA2-2-11/V0/T5 is an analog valve amplifier/control board for proportional hydraulic applications. The supplied listing identifies the unit with material number R900979888.
Bosch Rexroth documentation identifies material number R900979888 as the VT-VRPA2-2-1X/V0/T5 variant. It is designed for direct-operated proportional directional valves, including the 4WRE 10 series 2X. The T5 option provides selectable ramp-time functions for controlled hydraulic response.
For replacement purposes, the complete type designation, material number, revision, connector arrangement, and application should be checked against the installed unit before commissioning.
📋 Product Datasheet
| Parameter | Specification |
|---|---|
| Brand | BOSCH REXROTH |
| Model | VT-VRPA2-2-11/V0/T5 |
| Material Number | R900979888 |
| Product Series | VT-VRPA2 Electric Amplifier |
| Product Name | Analog Valve Amplifier / Control Board |
| Product Type | Proportional Hydraulic Valve Amplifier |
| Device Series | 1X |
| Customer Variant | V0 |
| Option | T5 – 5 Ramp Times |
| Supply Voltage | 24 VDC |
The official Bosch Rexroth catalog also specifies a 48-pin connection, analog control, and compatibility with 4WRE 10 series 2X valves.
⚙️ Key Features
- Bosch Rexroth VT-VRPA2 analog amplifier technology.
- Material number R900979888 for exact spare-part identification.
- T5 option with five selectable ramp-time settings.
- Designed for proportional directional valve control.
- Supports differential ±10 V command-value input.
- Provides additional command-value call-up inputs.
- Supports 4–20 mA current input.
- Eurocard-format printed circuit board design.
- Intended for rack installation in industrial hydraulic control systems.
🏭 Hydraulic System Application
The VT-VRPA2-2 variant is intended for control of direct-operated proportional directional valves in hydraulic systems. Bosch Rexroth documentation specifies the VT-VRPA2-2 for 4WRE10 series 2X valves.
Typical applications include:
- Industrial hydraulic machinery
- Machine tools
- Injection and forming equipment
- Material-handling machinery
- Hydraulic positioning systems
- Proportional flow and directional control
- Legacy Bosch Rexroth hydraulic control cabinets
The amplifier processes command signals and provides the control interface between the machine automation system and the proportional hydraulic valve.
🔌 Electrical & Interface Information
The VT-VRPA2 family uses analog command-value processing. Available inputs include:
- Differential command input: ±10 V
- Four callable command-value inputs: ±10 V
- Current input: 4–20 mA
- 24 V control signals for selected functions
- Ramp-time selection through the T5 configuration
The standard card is designed in 100 × 160 mm Eurocard format with a 48-pin DIN 41612 Form F connector.
🔧 Installation & Maintenance
Before installation, isolate the hydraulic system and electrical supply according to the machine’s maintenance procedure.
- Record the original amplifier type and material number.
- Photograph the existing wiring and connector position.
- Confirm R900979888 and the complete VT-VRPA2 designation.
- Check the 48-pin connector for bent, oxidized, or damaged contacts.
- Verify the rack position and mechanical mounting.
- Confirm the 24 VDC supply before energizing the card.
- Check the connected valve type and machine configuration.
- Verify ramp-time settings and command-value configuration.
- Restore power and check the amplifier’s status indicators.
- Perform a controlled hydraulic test before normal production.
Do not adjust sealed calibration components unless the machine commissioning procedure specifically requires it. Bosch Rexroth documentation notes that adjustment of certain sealed potentiometers can affect warranty conditions.
🛠️ Troubleshooting
No amplifier response:
Check the 24 VDC supply, rack connection, enable signal, connector contacts, and command-value input.
Valve does not respond correctly to the command:
Verify the ±10 V or 4–20 mA signal, command-value configuration, polarity, and associated hydraulic valve.
Ramp response is incorrect:
Check the selected T5 ramp-time setting and associated control inputs.
System reports an amplifier or valve fault:
Inspect the wiring between the amplifier and proportional valve, then verify the valve coil and feedback/control configuration.
Replacement card behaves differently from the original:
Compare the complete type designation and option code. Do not substitute another VT-VRPA2 variant solely because the front-panel appearance is similar.
✅ First-Operation Checklist
- Confirm material number R900979888.
- Confirm complete VT-VRPA2 type designation.
- Verify T5 option.
- Check 24 VDC supply.
- Inspect the 48-pin connector.
- Confirm correct rack position.
- Verify proportional valve compatibility.
- Check ±10 V / 4–20 mA command signals.
- Verify ramp-time configuration.
- Perform a controlled hydraulic test.
❓ FAQ
What is Bosch Rexroth R900979888?
R900979888 is the Bosch Rexroth material number associated with the VT-VRPA2-2-1X/V0/T5 analog valve amplifier.
What does T5 mean?
T5 identifies the five-ramp-time option used for selectable ramp functions in the VT-VRPA2 amplifier.
What valves can the VT-VRPA2-2 control?
Bosch Rexroth specifies the VT-VRPA2-2 for direct-operated proportional directional valves in the 4WRE10 series 2X family.
Is R900979888 the same as every VT-VRPA2-2 board?
No. Different VT-VRPA2-2 variants can have different sequence numbers and options. The complete type code and material number should be matched before replacement.
Can this board be used as a replacement spare?
Yes, when the existing hydraulic system is configured for the corresponding VT-VRPA2 variant and the electrical, valve, and control-system requirements are confirmed.
🔟 Related BOSCH REXROTH Models / Modules
- VT-VRPA2-2-1X/V0/T5 — Analog Valve Amplifier
- VT-VRPA2-2-1X/V0/T1 — Analog Valve Amplifier
- VT-VRPA2-1-1X/V0/T1 — Analog Valve Amplifier
- R900979887 — VT-VRPA2-1-1X/V0/T1
- R900979888 — VT-VRPA2-2-1X/V0/T5
- R900979889 — VT-VRPA2-2-1X/V0/T1
- VT-VRPA2 Series — Proportional Valve Amplifiers
- 4WRE6 Series 2X — Compatible Proportional Directional Valve Family
- 4WRE10 Series 2X — Compatible Proportional Directional Valve Family
- VT-VRPA Series — Bosch Rexroth Analog Amplifier Family
Related models are provided for spare-parts planning. They are not direct substitutes unless the complete electrical configuration, valve type, sequence number, and option code are confirmed.
📦 Spare-Parts & Lifecycle Planning
For legacy hydraulic equipment, keeping an exact VT-VRPA2 replacement can reduce troubleshooting time and minimize extended machine downtime.
Recommended inventory practices include:
- Primary spare: Keep at least one verified R900979888 unit for critical machines.
- Incoming inspection: Verify material number, type code, connector condition, and board condition.
- Functional testing: Record test results before placing the spare into long-term inventory.
- ABC classification: Treat critical hydraulic control amplifiers as high-impact maintenance spares.
- Buffer stock: Increase safety stock when the equipment is production-critical or replacement lead times are uncertain.
- Lifecycle planning: Monitor availability of legacy VT-VRPA2 variants and plan procurement before emergency replacement is required.
- Compatibility records: Store the exact amplifier type, valve type, machine application, and configuration information with the spare.
