Mitsubishi Q80BD-J71BR11 MELSECNET/H Interface Board

The Mitsubishi Q80BD-J71BR11 is a MELSECNET/H interface board for the MELSEC Q series PLC. It enables high-speed network communication between multiple PLCs, remote I/O stations, and other MELSECNET/H-compatible devices. The J71BR11 supports both remote I/O and data link functions, allowing distributed control systems to share data seamlessly. It uses optical fiber or coaxial cable (depending on the version) to provide noise-immune communication. The board is installed in a Q series base unit and communicates with the CPU via the backplane bus.

Technical Specifications

Network type: MELSECNET/H (remote I/O and data link). Communication speed: 10 Mbps (with coaxial) or 10/25 Mbps (with optical fiber). Connection distance: up to 1 km (with coaxial), up to 30 km (with optical fiber). Number of stations: up to 64. Data capacity: 8192 bits (link relay), 2048 words (link register). Power consumption: 5 V DC, 0.5 A from backplane. Dimensions: 90 mm × 27.8 mm × 110 mm. Weight: 0.2 kg. Operating temperature: 0°C to 55°C. Storage: -20°C to 75°C. The board includes LED indicators for communication status (RUN, ERR, LINK). Communication cable: coaxial (A6BRC-xxx) or optical fiber (A6BA-xx).

Key Features

• MELSECNET/H network interface for Q series

• Supports remote I/O and data link functions

• High-speed communication (10/25 Mbps)

• Long-distance communication up to 30 km (fiber)

• Up to 64 stations per network

• Optical or coaxial cable connection

• LED diagnostics for network status

• Compatible with Q series CPUs

Network Functionality

The J71BR11 provides two primary functions: remote I/O (RIO) and data link. In remote I/O mode, the board acts as a master or slave, controlling remote I/O modules distributed across the factory floor. In data link mode, it enables cyclic data sharing between multiple PLCs, allowing coordinated control without complex programming. The network supports both polling and token-passing methods. The board automatically manages network synchronization and error detection.

Installation and Wiring

Install the board in an I/O slot of a Q series base unit. Connect the MELSECNET/H cable (coaxial or optical) to the board's connector. For coaxial, use the appropriate terminator (A6BRC-TER) at both ends. For optical fiber, ensure the TX and RX cables are correctly connected. Set the station number and network mode via DIP switches on the board. After installation, configure the network parameters using GX Works2: set the link assignments and refresh settings. The board does not require external power; it is powered from the backplane.

Applications

The J71BR11 is used in distributed control systems where multiple PLCs need to share data and coordinate operations. Typical applications include automotive assembly lines (coordinating multiple PLCs), material handling systems (remote I/O for conveyors), process control in chemical plants, and large manufacturing systems requiring high-speed data exchange.

Maintenance and Troubleshooting

LEDs: RUN (green), ERR (red), LINK (yellow). If ERR is on, check the cable connection, station number, and termination. The board stores network error logs accessible via GX Works2. No user-serviceable parts.

Conclusion

The Mitsubishi Q80BD-J71BR11 MELSECNET/H interface board provides high-speed, reliable communication for distributed Q series PLC systems. Its long-distance capability and support for remote I/O make it suitable for factory-wide automation networks.