Control and communications link (abbreviated as CC-Link) was developed by Mitsubishi as a company-internal field bus network for coupling its own products with each other for the purpose of automation. Because of the large demand by the customers, it was sold as an open network. It is open, in the sense that the protocols for transmission of data are available for all companies that want to produce their own interfaces. The CLPA (CC-Link Partner Association) was founded in order for network technology to develop further and as a productive solution for applications.
At present, there are four basic versions of CC-Link on the market and they supplement each other and cover different aspects of automation and communication:
- The standard CC-Link is a network for automation, which can transmit information as well as control data at high speed and in doing so it ensures an integrated, productive process / plant automation. This network on the control and manufacturing level connects a wide range of devices at high speed as well as the deterministic exchange of data via one line. CC-Link is available in two different variants, which always vary from each other in the number of data that can be exchanged between at least two networks.
- CC-Link safety meets the requirement of recognizing errors that could lead to a fault. This function simply brings machines to a safe state when an error is recognized. It is reached whereby, for the first layer of the CC-Link, a level with the safety function is added which recognizes all errors during the transmission of data. CC-Link Safety is an expansion of the simple CC-Link and together with CC-Link Safety, it permits the connection of standard CC-Link devices to the same networks.
- CC-Link/LT is a bit-oriented system that was created for the use of actuators and sensors. It reduces and simplifies work involving the connection of devices with the main circuit. In addition, lines with up to 3-wires can be used. CC-Link/LT is based on CC-Link technology. Errors during connection are prevented by profiled lines and the installation time is also minimized.
- CC-Link IE uses Ethernet technology for error-free exchange of data on all levels of an installation – from the first level through to the manufacturing level. CC-Link IE is available as a control network in different variants, but is always based on the principle of the standard version. CC-Link IE was developed for the exchange of large data in an installation, while CC-Link IE was optimized for connecting different devices in existing networks.
Nowadays, many engineers select the network technology CC-Link within the automation system. Simple installation and the rapid commissioning of new production lines are convincing proof of this technology. Several advantages, such as high reliability, prove themselves after a short duration once implemented in the high-speed network.
Reliability is an elementary component in automobile production and the selection of the field bus is a decisive factor for error-free processes. As such, many engineers in the field of assembly and paint shops decide for equalisation on the basis of the open CC-Link technology. This is characterized by rather fast transmission of data and high performance in terms of strength. The elementary advantage of the network is the range, which is up to approximately 14 km. Furthermore, in use, the CC-Link provides convincing proof of its advantages under the difficult framework conditions that can occur in factories. During production, each vehicle travels for approximately 20 km in a production plant and passes a large number of assembly, painting and welding stations. This extensive assembly line is operated by so-called converters, whose data are run through the CC-Link network. This ensures that each part of the vehicle is at the planned location at the planned time. Assembly processes and certain welding procedures are elementary components of the production department. Up to five network masters are responsible for the entire transmission of data in these areas.
The network master enables transmission between the devices of operation in the chassis construction section, while the other four network masters control the conveyance systems, welding installations, and robots. The stable technology reliably connects over 125 operating devices in a chassis assembly line. In automobile production, it also enables the transmission of data for controlling the device that picks up or shapes large chassis components. The network furthermore coordinates and controls a large number of robots in the manufacturing line. In this way, each movement can be carried out in a targeted way, e.g. the positioning, conveying and welding of different car parts. Via the network, the robots inform each other of their positions and in doing so, prevent errors and collisions. Overall, approximately 400 robots are connected with each other by CC-Link in the assembly area. Throughout the different automobile manufacturing areas, the network also transmits information to and from the different programmable controllers and operating devices of the different cells. Almost 90 % of the control units in automobile production are connected to each other via this network.