Mitsubishi AJ71QLR21 Network Module Inquiry Item

This Mitsubishi AJ71QLR21 is a MELSECNET/10 coaxial token ring network module for MELSEC-QnA large PLC series. It is used to build redundant coaxial ring control network between multiple PLC stations. It adopts token ring transmission mode with 10Mbps communication speed, supports PLC to PLC data exchange and remote I/O communication. The dual-loop structure can realize loop back function when cable fails, to keep the network running continuously. This model has been discontinued for many years, it is only used as maintenance spare part for legacy production lines, metallurgy, chemical and power old control cabinets.

Specifications

Model: AJ71QLR21 Brand: Mitsubishi Applicable CPU: MELSEC-QnA series Network protocol: MELSECNET/10 Transmission type: Coaxial token ring Communication speed: 10Mbps Topology: Redundant dual ring Cable: 75Ω coaxial cable Installation: QnA rack slot Certifications: CE

Components & Troubleshooting

Network communication processing chip, coaxial transceiver circuit, ring back control circuit, status LED indicator, coaxial signal terminal, gold-plated backplane connector, plastic module housing. Common faults: network ring break alarm, station cannot join network, intermittent communication dropout, module self-check error, coaxial interface damage.

Disclaimer

This spare part shall be installed, calibrated and maintained by qualified instrument technicians. Confirm station number and network parameters before commissioning.