1 Gbps deterministic ring for Q-series backplane
The QJ71GP21-SX is a CC-Link IE Controller Network Unit that fits a Q-series PLC rack, giving the controller a 1 Gbps deterministic fiber-optic ring for motion and I/O coordination across up to 120 stations. It uses the token-ring method over a double-loop topology, which means a single fiber break self-heals and the network keeps running — the ring reverses direction and the link stays up. The physical layer is 1000 BASE-SX over multimode GI fiber with a double LC connector, giving a 550 m maximum inter-station distance and a total extension of 66 km with 120 units in the ring.
Link data capacity and station count
Each station can map up to 16 K points of LB (link relay) data in standard mode, expandable to 128 K points in extended mode — that is 256 K bytes of shared bit data per station when you need it. The per-station LX (link input) and LY (link output) each hold 8 K points (1 Kbyte), so the cyclic data exchange covers 32 I/O points of occupied intelligence on the backplane. Up to 239 networks are addressable, with 32 groups maximum per network, and the transient transmission payload tops out at 1920 bytes for parameter or diagnostic data outside the cyclic exchange.
Panel integration and power budget
The module draws 0.85 A from the 5 VDC backplane rail — a Q-series power supply needs to budget this alongside the CPU and other special-function modules in the rack. It is a Class 1 laser product per JIS C 6802 and IEC 60825-1, so no special eye-safety precautions are needed during installation or maintenance — the fiber output is inherently safe under normal use.
Typical lead time runs 1–10 working days for stock-holding distributors; volume or project-level pricing is confirmed at RFQ time.