Description
The Schneider Electric (formerly Modicon) NW-BM85C002 is a high-performance Modbus Plus Bridge/Multiplexer, commonly referred to as a Bridge Plus. This specialized networking device is designed to facilitate communication between multiple Modbus Plus (MB+) networks or to act as a sophisticated multiplexer for connecting standard Modbus (RS-232) devices into a high-speed Modbus Plus architecture.
Product Parameters (Datasheet)
- Model Number: NW-BM85C002
- Device Type: Modbus Plus Bridge / Multiplexer
- Ports: * 2 x Modbus Plus Ports (DB9)
- 4 x Modbus RS-232 Ports (RJ45 or DB9 via adapters)
- Communication Rate: 1 Mbps (Modbus Plus) / Up to 19.2 kbps (Modbus Serial)
- Redundancy: Supports dual-cable Modbus Plus redundancy
- Power Supply: 115/230 V AC (Internal) or 24 V DC (Model dependent)
- Mounting: 19-inch Rack mount or Desktop/Shelf mount
- Isolation: Full galvanic isolation between ports and power
Country of Origin
This networking component was engineered and manufactured by Schneider Electric (Modicon), historically in the USA or France, depending on the production era of the Modicon Quantum/984 series.
Schneide NW-BM85C002
Schneide NW-BM85C002
Schneide NW-BM85C002
Application Fields
The NW-BM85C002 is a critical infrastructure component for legacy and large-scale industrial networks:
- Network Bridging: Connecting two separate Modbus Plus networks to allow cross-network data exchange while maintaining electrical isolation.
- Large-Scale SCADA: Interfacing multiple PLC clusters (Modicon Quantum or Premium) to a central monitoring station.
- Legacy Device Integration: Multiplexing older serial Modbus devices (drives, power meters, or weigh scales) into a modern MB+ backbone.
- Network Extension: Overcoming distance limitations or node-count restrictions of a single Modbus Plus segment.
- Data Concentration: Gathering data from four independent serial lines and making it accessible via a single MB+ node address.
Product Usage Instructions
- Network Topology Planning: Determine if the unit will act as a “Bridge” (MB+ to MB+) or a “Multiplexer” (MB+ to Serial). Set the internal dip switches or jumpers to define the operating mode.
- Node Addressing: Assign a unique Modbus Plus node address to the bridge using the rotary switches or configuration software. Ensure no address conflicts exist on either network segment.
- Physical Connection: Use standard Modbus Plus drop cables and T-taps to connect the MB+ ports. For serial devices, ensure the pinout of the RS-232 ports matches the target device.
- Configuration: Use the BP85 configuration utility to define routing tables, port speeds, and parity settings.
- Diagnostics: Monitor the “Active” and “Error” LEDs. A steady green LED indicates a healthy token rotation on the Modbus Plus network.
Product Technical Description
The NW-BM85C002 operates as a sophisticated store-and-forward device. Technically, it manages the Token Passing protocol of the Modbus Plus network at 1 Mbps while simultaneously managing the polling logic for the four serial RS-232 ports. When configured as a bridge, it filters traffic based on a routing table, only passing messages destined for the opposite network segment, which reduces overall network congestion. It provides a robust electrical barrier between segments, protecting the entire system from localized surges or grounding issues. The “002” variant is often sought for its specific port density and compatibility with the Modicon 984 and Quantum hardware lifecycles.
Q&A (Common Questions)
- Q: Can this bridge connect Modbus Plus to Ethernet (Modbus TCP)?
- A: No. The NW-BM85C002 is for MB+ and Serial Modbus. To bridge to Ethernet, you would need a 174CEV30020 (Modbus to Ethernet) or a BMXNOM0200 for newer platforms.
- Q: What is the maximum distance for a Modbus Plus segment using this bridge?
- A: A single segment is limited to 450 meters (1500 feet), but using the bridge can effectively “reset” the distance limit for the subsequent segment.
- Q: Is this module still in active production?
- A: This is a legacy Modicon component. While Schneider Electric provides support, it is largely replaced by newer Ethernet-based communication architectures in the Modicon M580 series.
- Q: Does it support 4-wire RS-485?
- A: The native ports are RS-232. To connect to RS-485 devices, an external RS-232 to RS-485 converter is required for each port.
Similar Model Recommendations
- Schneider NW-BM85002: Standard Bridge variant.
- Schneider 174CEV30020: Modbus to Ethernet bridge.
- Schneider 140NOM21100: Quantum Modbus Plus Communication Module.
- Schneider 140NOE77101: Quantum Ethernet Communication Module.
- Schneider AS-J890-001: Legacy Modicon Modbus Plus tap/connector.
For technical documentation or a quote for the Schneider Electric NW-BM85C002, please contact our network engineering specialists.
