NEW Mitsubishi PLC Module AJ71QBR11 or A J71QBR11

Mitsubishi AJ71QBR11 Coaxial Bus Network Module

Overview

The AJ71QBR11 is a MELSECNET/10 network module used with Mitsubishi control systems in the MELSEC-QnA context.

Mitsubishi’s hardware manual identifies it specifically as the coaxial bus type module, and the same manual shows it as part of the network family used for control stations, normal stations, and remote master stations in MELSECNET/10.

Published Mitsubishi network specifications show that AJ71QBR11 uses a single coaxial bus transmission format, supports PLC-to-PLC network and remote I/O network structures, and uses 3C-2V or 5C-2V coaxial cable.

The module is also listed in Mitsubishi discontinuation and transition materials, which signals that it is now mainly an installed-base support item rather than a new-network standard.

Application Value

The AJ71QBR11 is best suited to legacy Mitsubishi networked PLC systems where a coaxial bus architecture is already in place and needs to be maintained.

In practical installations, that means machine cells, production lines, or remote I/O networks where the wiring, termination, and station structure were originally designed around MELSECNET/10 coaxial communication. 

This application view follows directly from the module’s published transmission route and network-role descriptions.

Its value is especially clear in maintenance and phased upgrades.

Mitsubishi’s transition documents continue to mention AJ71QBR11 when discussing migration from older MELSEC-A/QnA networking hardware, which suggests that many users still need the module to keep existing coaxial networks running while planning a longer-term modernization path.

Replacement and Selection Perspective

For replacement work, AJ71QBR11 should be treated as a network-architecture-specific module, not just as a generic communications card.

The coaxial bus topology, cable type, termination arrangement, station count, and surrounding MELSECNET/10 layout all matter. 

In real service work, matching the same module family helps preserve the original communications behavior and reduces the chance of avoidable network faults after installation. This is an engineering recommendation based on the published cable, topology, and network-role details in Mitsubishi’s hardware manual.

Technical Data

FAQ

Q1: What kind of module is AJ71QBR11?
It is a MELSECNET/10 coaxial bus network module, identified in Mitsubishi’s hardware manual as the coaxial bus type member of the network family.

Q2: What makes this module different from a general communications card?
Its function is tied to a very specific network structure: single coaxial bus, MELSECNET/10, and the corresponding station roles used in that architecture.

In practice, that makes it far more system-specific than a generic serial or Ethernet module.

Q3: What applications is it best suited for?
It fits legacy Mitsubishi PLC networks and remote I/O systems where coaxial MELSECNET/10 communication is already installed and needs to be preserved.

That use profile follows directly from the module’s published network functions.

Q4: Why do cable type and topology matter so much here?
Because the module is designed around a specific physical network layer.

The published data ties it to 3C-2V / 5C-2V coaxial cable and a single coaxial bus structure, so those details directly affect whether the network will operate correctly after replacement.

Q5: What should be checked before ordering?
Check the installed part number, confirm that the network is MELSECNET/10 coaxial bus, verify the cable type and termination arrangement, and make sure the station role matches the existing system.

Those checks usually matter more than outward similarity.