Understanding CC-Link Industrial Communication Protocols

CC-Link (Control & Communication Link)

CC-Link is an open, industrial fieldbus and industrial Ethernet communication protocol developed by the CC-Link Partner Association (CLPA) (founded by Mitsubishi Electric). It enables real-time, high-speed data exchange between controllers (PLCs), I/O devices, drives, HMIs, and other industrial equipment—supporting both discrete manufacturing (e.g., automotive assembly) and process control (e.g., chemical plants). CC-Link is widely used in Industry 4.0 architectures for its scalability, reliability, and compatibility with multi-vendor equipment.

1. Core CC-Link Family Protocols

The CC-Link family includes multiple protocols tailored to different industrial communication needs:

Protocol	Type	Speed	Key Use Cases
CC-Link	Fieldbus	10 Mbps (max)	Traditional discrete control (e.g., PLC-to-I/O, PLC-to-PLC communication).
CC-Link/LT	Lightweight Fieldbus	156 kbps–10 Mbps	Cost-effective, small-scale applications (e.g., sensor/actuator networks).
CC-Link IE Basic	Industrial Ethernet	1 Gbps	Mid-range industrial Ethernet (e.g., factory floor device connectivity).
CC-Link IE Control	Industrial Ethernet	1 Gbps/10 Gbps	High-performance real-time control (e.g., motion control, synchronized production lines).
CC-Link Safety	Safety Protocol	Integrated with CC-Link/IE	Functional safety communication (SIL 3/PLe certified) for emergency stops, safety sensors.

Key Features of CC-Link IE Control (Flagship Protocol)

Determinism: Cycle times as low as 1 ms for real-time control (critical for motion control and high-speed production).
Bandwidth: 10 Gbps for large-scale data transmission (supports video, IoT data, and control signals over a single network).
Network Topology: Supports star, linear, and ring topologies (ring topology provides redundancy for fault tolerance).
Multi-Vendor Compatibility: Over 3,000 certified products from 200+ manufacturers (Siemens, Rockwell, Omron, etc.).

2. Core Characteristics of CC-Link

2.1 Real-Time Performance

CC-Link uses a cyclic communication method (fixed data update intervals) to ensure deterministic data transfer—critical for time-sensitive applications like motion control or high-speed assembly lines.
For CC-Link IE Control, “Time-Sensitive Networking (TSN)” support enables coexistence of real-time control data and non-critical data (e.g., monitoring, diagnostics) on the same network.

2.2 Scalability

CC-Link (Fieldbus): Supports up to 64 slave stations per network, with a maximum transmission distance of 1.2 km (without repeaters).
CC-Link IE (Ethernet): Scales to thousands of devices across multiple subnets, with transmission distances up to 100 km (via fiber optics).

2.3 Multi-Vendor Openness

As an open standard (ISO 15745 compliant), CC-Link is not tied to a single vendor. The CLPA certifies third-party products to ensure interoperability, allowing users to mix equipment from different manufacturers (e.g., a Mitsubishi PLC with Siemens drives).

2.4 Integrated Safety

CC-Link Safety embeds safety communication within the standard CC-Link/IE network (no separate safety cabling), reducing installation costs and complexity. It meets global safety standards (EN ISO 13849-1, IEC 61508) for machine safety.

2.5 IoT/Industry 4.0 Enablement

CC-Link IE TSN supports OPC UA over TSNA (Time-Sensitive Networking Alliance), enabling seamless data exchange between shop-floor devices and cloud/enterprise systems (e.g., MES, ERP, predictive maintenance platforms).
The CC-Link IE Field Network integrates with edge computing devices to process data locally, reducing latency for real-time decisions.

3. CC-Link Network Structure

A typical CC-Link network consists of three main components:

3.1 Master Station

Usually a PLC (e.g., Mitsubishi Q-series, L-series) that controls the entire network, initiates data exchange, and manages slave stations.
Responsible for setting communication parameters (baud rate, cycle time) and monitoring network health.

3.2 Slave Stations

Devices that respond to commands from the master station, including:
- Remote I/O Stations: Digital/analog input/output modules (e.g., Mitsubishi AJ65SBT series).
- Intelligent Devices: Drives, HMIs, safety relays, or RFID readers with built-in CC-Link communication.
- Local Stations: Additional PLCs connected as slaves for distributed control.

3.3 Communication Media

CC-Link (Fieldbus): Twisted-pair cable (shielded or unshielded) or fiber optics.
CC-Link IE (Ethernet): Cat 5e/Cat 6 copper cable (for 1 Gbps) or single-mode/multi-mode fiber (for 10 Gbps/long distances).

4. Key Use Cases

4.1 Discrete Manufacturing

Automotive assembly lines: Synchronized control of robots, conveyors, and welding equipment via CC-Link IE Control (cycle times < 1 ms ensure precise motion coordination).
Electronics manufacturing: High-speed data exchange between pick-and-place machines, inspection systems, and PLCs.

4.2 Process Control

Chemical/petrochemical plants: CC-Link LT for connecting field sensors (temperature, pressure) and valves, with CC-Link IE for integrating process controllers and SCADA systems.
Food/beverage production: Real-time monitoring of filling machines, mixers, and packaging lines, with safety interlocks via CC-Link Safety.

4.3 Smart Factories (Industry 4.0)

Predictive maintenance: CC-Link IE TSN streams equipment health data (vibration, temperature) from sensors to edge/cloud platforms for anomaly detection.
Digital twins: CC-Link IE provides real-time data from physical assets to virtual models, enabling simulation and optimization of production processes.

4.4 Building Automation

Integrated control of HVAC systems, lighting, and security devices via CC-Link/LT, with centralized monitoring via CC-Link IE.

5. CC-Link vs. Other Industrial Protocols

Feature	CC-Link (IE Control)	Profinet IO RT	EtherNet/IP
Max Speed	10 Gbps (TSN)	1 Gbps (TSN optional)	1 Gbps
Cycle Time	< 1 ms	< 1 ms	~1 ms (for real-time)
Safety Integration	CC-Link Safety (integrated)	Profisafe	CIP Safety
IoT Support	OPC UA over TSNA	OPC UA over TSN	OPC UA
Multi-Vendor Products	3,000+ certified products	10,000+ certified products	8,000+ certified products
Topology	Star/linear/ring (redundant)	Star/linear/ring	Star/linear