The NDBU-95C is a high-performance optical communication branching unit designed by ABB for the DCS 600 series thyristor power converters and ACS 600 AC drive systems. It serves as a key component within the DDCS (Distributed Drive Communication System) architecture. This product is primarily used for high-speed, reliable fiber-optic communication networking among multiple frequency converters or DC drives in industrial drive systems, enabling centralized monitoring, parameter configuration, fault diagnosis, and data transmission.
As an enhanced version of the NDBU-95 series, the NDBU-95C is optimized for compatibility, communication stability, and configuration flexibility, making it suitable for drive system network deployment in various complex industrial environments. It supports tree, parallel, and mixed network topologies, effectively expanding system scale, improving communication distance, and enhancing anti-interference capability. It is an ideal choice for building the communication backbone of medium to large-scale drive systems.
2. Product Functions and Features
1. High-Speed Fiber-Optic Communication
Utilizes 10 MBd optical transceivers, supporting communication rates up to 4 Mbit/s (default setting is 1 Mbit/s).
Supports Plastic Optical Fiber (POF) and Hard Clad Silica (HCS) fiber, with maximum transmission distances of 30 meters and 200 meters, respectively.
Features automatic beam intensity adjustment, optimizing transmit power based on fiber length to ensure communication quality.
2. Multi-Channel Branching Capability
Provides 9 independent optical communication channels (CH0–CH8), each capable of connecting to one drive or a downstream branching unit.
Supports cascading and branch expansion; a single system can connect up to 25 branching units, suitable for large-scale drive systems.
3. Flexible Address Management and Topology Support
Employs a hierarchical address allocation mechanism, supporting address settings within the range of 124 to 76.
Supports tree, parallel, and mixed network structures, adapting to different site layouts and system architecture requirements.
Features a dedicated DDCS protocol mode, ensuring full compatibility with the DriveWindow configuration software.
4. High Reliability and Anti-Interference Design
Full fiber-optic communication, completely isolating electrical interference, suitable for industrial environments with high electromagnetic interference.
Each channel features independent optical power adjustment and disable functions; unused channels can be set to "DISABLED" status, reducing system noise and power consumption.
Incorporates comprehensive overcurrent and short-circuit protection mechanisms, ensuring long-term stable operation.
5. Convenient Configuration and Maintenance
Configurable via DriveWindow software with visual settings for communication rate, optical power, operating mode, and other parameters.
On-board DIP switches for address and communication speed settings, ensuring simple operation.
Equipped with abundant status indicators for easy on-site diagnosis and maintenance.
3. Application Scenarios and System Architecture
The NDBU-95C is suitable for the following typical industrial drive networking scenarios:
1. Tree Topology Structure
Suitable for hierarchical control and distributed-centralized systems. For example:
A master PC connects via an NISA-03 interface card to the first NDBU-95C, which then branches out step-by-step to individual drives.
Applicable to scenarios like segmented production line control and multi-motor cooperative operations.
2. Parallel Topology Structure
Suitable for scenarios with multiple parallel-running subsystems requiring highly reliable redundant communication. For example:
Multiple NDBU-95C units are connected in parallel to the same master station, achieving channel redundancy and load balancing.
Commonly used in large fan systems, pumping station control, etc.
3. Mixed Topology Structure
Combines tree and parallel structures, suitable for complex, large-scale systems. For example:
Combines multi-level branching with parallel connections for flexible expansion and high reliability.
Applicable to large drive systems in industries like steel, cement, and mining.
4. Configuration and Installation Guide
1. Hardware Settings
Address Setting: Set the unit address via DIP switch S1. The higher the address value, the closer the unit is to the master station.
Communication Rate: Select 1/2/4 Mbit/s via switch X12.
Operating Mode: Select DDCS mode via switch X13.
Optical Power Setting: Set the transmit power for each channel according to the actual fiber length, referring to the configuration tables.
2. Software Configuration (DriveWindow)
Connect the PC to the first NDBU-95C and open the DriveWindow software.
Select the appropriate link rate and beam intensity in the "Optical Link Settings" window.
Enable the "Auto Node Numbering" function; the system will automatically identify all branching units and drives.
3. Fiber-Optic Cabling Recommendations
Use fiber cables that meet specifications, avoiding excessive bending or stretching.
For long-distance transmission, HCS fiber is recommended; POF can be used for short distances.
Clean fiber connectors before connection to ensure clear optical paths.
5. Safety Usage and Maintenance
1. Safety Precautions
Read the safety chapter in the DCS 600 Operating Instructions before installation or maintenance.
Ensure the system is powered off before performing hardware connections or switch settings.
Avoid looking directly into the fiber optic ports to prevent laser eye injury.
2. Regular Inspection
Check fiber connections for looseness, contamination, or damage.
Monitor the communication status indicators on each channel to promptly detect abnormalities.
Regularly back up DriveWindow configuration parameters.
3. Fault Diagnosis
If communication is interrupted, check if address settings, fiber links, and optical power configurations are correct.
An optical power meter can be used to detect the transmit and receive optical power of each channel.
In case of hardware failure, contact ABB authorized service personnel.
6. Supporting Products and Accessories
| Supporting Product Model | Description |
| NISA-03 | DDCS/ISA Bus Interface Card, for desktop PCs |
| NDPC-12 | DDCS/PC Card Fiber-Optic Cable (10 MBd) |
| NDPA-02 | DDCS/PC Card Adapter |
| NAME-11/21 | AMC Communication Module (for ACS 600) |
| SDCS-AMC-DC | AMC Communication Board (for DCS 600) |
| NDCO-01/03 | Fiber-Optic Connector Kit |
