Description
- Model: VT-HNC100-1-23W-08-P-0
- Material Number: R900958999
- Brand: Bosch Rexroth
- Series: HNC100 (Digital Axis Control for Hydraulic Drives)
- Core Function: Programmable digital bus-compatible control for one hydraulic axis
- Product Type: NC Control Module
- Key Specs: 24 V DC supply, 1 hydraulic axis control, Profibus DP interface (P), specialized for closed-loop control of position, force, or pressure.
- Component Series: 2X (indicated by the “-2” in the model code)
- Axis Control: 1-axis configuration
- Communication Interface: Profibus DP (indicated by “-P-“)
- Digital Inputs/Outputs: 8 digital inputs, 8 digital outputs (standard configuration)
- Analog Interfaces: Integrated interfaces for position transducers (SSI or incremental) and pressure sensors (4–20 mA or 0–10 V)
- Mounting: 35 mm DIN rail or wall mounting (housing design)
- Software: WIN-HNC configuration software required for parameterization
- Protection Class: IP 20
- Operating Voltage: 24 V DC (+20% / –10%)
REXROTH VT-HNC100-1-23W-08-P-0 R900958999
Application Scenarios & Pain Points
The VT-HNC100-1-23W-08-P-0 is a specialized digital controller designed to bridge the gap between high-level PLCs and the precise, heavy-duty world of hydraulics. It is the “brain” that tells a hydraulic cylinder exactly where to stop or how much pressure to apply. In plastic injection molding or metal pressing, if the HNC100 drifts or loses its tuning parameters, you end up with scrap parts or, worse, mechanical damage to the expensive molds.
1. Metal Forming & Presses
Managing the synchronization and pressure ramping of hydraulic rams in stamping and forging presses.
2. Plastic Injection Molding
Controlling the injection speed and clamping force where millisecond response times are needed to ensure part quality.
3. Woodworking & Paper Machinery
Utilized for high-speed positioning of saws or rollers where hydraulic power is required for force, but digital precision is required for dimensions.
Case Study: The “Jittery” Press Brake
Background: A metal fabrication plant was using an R900958999 controller on a heavy-duty press brake. Suddenly, the ram started “jittering” during the final approach, leading to uneven bends.
The Problem: The maintenance team replaced the hydraulic valves and the position sensor, but the jittering remained. We diagnosed the HNC100 and found that the internal analog-to-digital converter (ADC) for the feedback loop had become unstable due to electrical noise and heat aging over 10 years of service.
The Solution: We supplied a new VT-HNC100-1-23W-08-P-0. Before shipping, we uploaded the customer’s original parameter set (saved via WIN-HNC) to ensure the PID loops were pre-configured for their specific machine dynamics.
The Result: The press brake was back in production within hours of the module arriving.
- Avoided Loss: Prevented a total shutdown of the bending line, which was costing the plant $15,000 per shift in delayed orders.
- Takeaway: Hydraulic “jitter” is often an electronic control issue, not a mechanical one. If your PID tuning hasn’t changed but the behavior has, the HNC100 hardware is likely failing.
REXROTH VT-HNC100-1-23W-08-P-0 R900958999
Compatible Replacement Models
| Original Model | Replacement Model | Compatibility | Key Differences | Workload |
| VT-HNC100-1-20 | VT-HNC100-1-23W | ✅ Direct | Newer series (2X) replaces 1X | Minor (Check wiring) |
| VT-HNC100-1-23W-08-C | VT-HNC100-1-23W-08-P | ❌ No | “C” is CAN-bus; “P” is Profibus | Bus redesign required |
| R901031332 | R900958999 | ✅ Direct | Different material numbers for same spec | Plug & Play |
Engineer’s Advice: Rexroth HNC100 modules are highly specific. The suffix “-P-“ means it communicates via Profibus. If your existing unit has a “-C-“ or “-E-“, they are not interchangeable because the communication hardware inside is physically different. Always match the material number R900958999 exactly.
REXROTH VT-HNC100-1-23W-08-P-0 R900958999
Troubleshooting Quick Reference
| Symptom | Possible Cause | HNC100 Related? | Quick Check | Action |
| “Status” LED Red | Internal Hardware Fault | ✅ High | Power cycle the unit | Replace module |
| “Bus” LED Flashing | Profibus Comm Error | ✅ High | Check Profibus address & cabling | Verify PLC connection |
| Axis Won’t Move | Enable Signal Missing | ⚠️ Medium | Check Digital Input 1 (Enable) | Check wiring to PLC |
| Position Drift | SSI/Encoder Error | ⚠️ Medium | Check sensor cable shielding | Replace feedback cable |
Expert Maintenance Tips:
- Parameter Backups: ❗ Critical! The HNC100 is useless without its configuration file. Always keep a backup of your
.hncproject file on a separate drive. If the module fails, you can’t “suck” the program out of a dead unit. - Shielding is King: Hydraulic environments are electrically noisy. Ensure the Profibus and feedback cables are properly shielded and grounded at the HNC100 end. 90% of “intermittent faults” are caused by poor grounding.
- The 24V Rail: The HNC100 is sensitive to voltage drops when hydraulic valves fire. Use a dedicated, stabilized power supply for the controller to prevent “reboot” glitches.
