An Application Layer Protocol for Industrial Automation
CC-Link (Control & Communication Link) is an integrated family of open networks originally developed by Mitsubishi Electric. It is designed for ease of use, simplicity of system design, speedy installation, and reliability in operation. It provides high speed, deterministic communication linking a wide range of multi-vendor automation devices over a single cable.
CC-Link is the leading open networking technology in Japan and Asia and is growing strongly in North America and Europe. For automation equipment producers selling into these markets, integration of the dominant open network is the obvious choice for maximizing network compatibility. Many major European device makers are now incorporating CC-Link compatibility because of its strength in Asia.
CC-Link Familty of Networks
There are four fully compatible open technology CC-Link networks. They can be used together in an integrated solution, or separately as needed: CC-Link/LT, CC-Link Safety, CC-Link, CC-Link IE Controller, CC-Link IE Fields. We will cover CC-Link IE Fields in greater detail in this piece.
CC-Link IE Field
CC-Link IE Field is a 1-Gigabit Ethernet based integrated network designed to meet the changing demands of optimized control, openness, reliable, and deterministic handling of data in industrial applications. It is supported and promoted by CC-Link Partner Association (CLPA). CC-Link IE enables seamless data communication from the plant-level enterprise network to the production floor network. This integrated industrial network philosophy also provides cost reduction for the total system engineering task from system start-up, operation, and maintenance. The biggest differentiation between CC-Link IE Field and other Ethernet based protocols is its High speed and determinism.
Key Features: Per the CLPA
One gigabit-per-second transmission and real-time protocol enables control of remote I/O field devices with essentially no transmission delay. This transmission rate is at least ten times faster than currently available Industrial Ethernet-based networks. CC-Link IE Field network is the first gigabit industrial Ethernet network extended down to the field device level. It combines the best of existing technologies and applies them in a highly reliable architecture that provides exceptional data bandwidth and transaction rates. The new network uses commercially available Cat5E cable and RJ45 connectors.
Inherent determinism without Ethernet switches
The significant difference between CC-Link IE Field Network and other Industrial Ethernet solutions is that CC-Link IE Field Network delivers deterministic control communications without requiring the addition of Ethernet switches. This feature eliminates the hardware costs and engineering implementation costs of those switches. Also, the cost and need for developing communication statements to govern the flow of data is eliminated due to the shared memory concept of CC-Link IE Field and no knowledge of CC-Link IE Field protocol is required. Determinism is guaranteed by the CC-Link IE Field token-passing technique.
A CC-Link IE Field Network allows for a topology best suited to the needs of the particular application — thus ensuring greatest flexibility. These topologies include star, line, mixed star and line, and ring. Within a single network there can be a total of 120 stations with up to 328 feet (100 meters) of Cat5E cable between each station. In addition, as many as 239 networks can be interconnected allowing vast exchange of data to suit any application.
CC-Link IE Field networking enables seamless communication of data from field devices to controllers and from controllers to other controllers in order to form an integrated network for transmitting data at gigabit speed. An Ethernet adapter enables connection to 100 Mb Ethernet devices. CC-Link IE Field provides seamless data transmission between automation controllers such as PLCs and computers and field devices such as digital and analogue I/O, pneumatic valve manifolds, RFID readers, variable speed drives, motion controllers and other factory assets. It currently enables up to 120 stations to be interconnected on a single network while providing deterministic data exchange at gigabit speed without the need for Ethernet switches.
Cyclic and Transient Messaging
CC-Link IE Field offers both “Cyclic” and “Transient” methods of data exchange based on well-proven token passing technology and an optimized protocol. Cyclic transmissions provide real-time, transparent data delivery services to all stations. A “common memory” model configured by a few simple parameter settings establishes deterministic data exchange for the entire network. Specific data delivery timing can be calculated accurately before a network is commissioned. The second method of CC-Link IE Field communication is the “Transient” mode. Transient messages are initiated “on-demand” from a specific station. Transient messages can be sent to one or more network stations and these stations can respond to Transient requests for data. CC-Link IE Field allocates Transient mode bandwidth so that cyclic communication remains deterministic.