Mitsubishi QJ71GP21-SX CC-Link IE Controller Network Module MELSEC Q

Product Overview

The Mitsubishi QJ71GP21-SX (QJ71GP21SX) is a high-speed, 1 Gbps industrial communication module designed for the MELSEC Q series PLC. Engineered for high-capacity data exchange in demanding sectors such as semiconductor manufacturing, automotive assembly, and large-scale logistics, this CC-Link IE Controller Network Unit utilizes an optical fiber double-loop topology to ensure maximum reliability. By facilitating seamless "Controller-to-Controller" communication, the QJ71GP21-SX enables complex synchronized operations across multiple PLC stations. Its primary value lies in its 1 Gbps bandwidth and redundant transmission paths, which virtually eliminate network bottlenecks and significantly reduce the risk of system-wide downtime caused by cable breaks.

Technical Configuration

The QJ71GP21-SX operates on the CC-Link IE Control platform, the industry's first 1 Gbps Ethernet-based integrated network. This module utilizes the Token Ring communication method over a double loop transmission path, providing inherent redundancy; if one path is severed, the network continues to operate via the loop-back function.

It supports a massive link capacity, handling up to 128 K points of Link Word (LW) data in extended mode, making it suitable for data-intensive applications like recipe management or complex motion coordination. The module interfaces via a double LC type connector, supporting multimode optical fiber (GI) that complies with 1000 BASE-SX standards. This optical infrastructure allows for a maximum inter-station distance of 550 m and a staggering total network extension of 66000 m when fully populated with 120 units.

Technical Specifications

Technical FAQs

Q1: What is the benefit of the "Extended Mode" in this module?

A1: Extended Mode significantly increases the maximum link points per station, specifically boosting Link Word (LW) capacity from 16 K points to 128 K points. This is essential for large-scale systems that require massive data transfers between PLCs without taxing the CPU cycle time.

Q2: What happens if an optical fiber cable is damaged during operation?

A2: Thanks to the "Double Loop" transmission format, the QJ71GP21-SX performs a loop-back operation. The network remains functional by using the remaining intact path, and the system generates a diagnostic error to alert maintenance without stopping the process.

Q3: Is the QJ71GP21-SX compatible with all MELSEC Q CPUs?

A3: It is compatible with most Q series CPUs, but the maximum number of stations depends on the CPU model. Universal model QCPUs support up to 120 stations, while High Performance model QCPUs are limited to 64 stations.

Engineering & Installation Guide

• Optical Fiber Maintenance: Always use a specialized optical connector cleaner before mating the LC connectors. Even microscopic dust particles on the GI fiber tip can cause signal attenuation at 1 Gbps, leading to intermittent CRC errors or link loss.

• Bend Radius Compliance: When routing the 1000 BASE-SX multimode fiber, strictly adhere to the manufacturer's minimum bend radius (typically 20-30 mm). Sharp bends can cause light leakage and permanent physical damage to the glass core, resulting in high optical loss.

• Laser Safety: This module is a Class 1 Laser product (JIS C 6802/IEC 60825-1). While safe under normal operation, never look directly into the optical ports or the end of a connected fiber cable while the module is powered, as invisible infrared laser radiation is present.