ControlNet

ControlNet is a real-time fieldbus network oriented to the control layer introduced in recent years, providing time-critical I/O data and message data on the same physical layer media link, including program upload/download, configuration data and end-to-end It is a highly deterministic and repeatable high-speed control and data acquisition network, and the I/O performance and end-to-end communication performance are greatly improved compared with traditional networks.

ControlNet is an open network first proposed by ControlNet International, Ltd.. Rockwell Automation put forward the concept of three-layer network at the beginning of the design, namely Ethernet, Controlnet network, Deveicenet network, upper layer information is used for data acquisition and program maintenance of the whole plant; middle layer automation and control layer realize real-time The control of I/O, the interlock of the controller and the transmission of the message; the underlying device network is used for low-cost, high-efficiency information integration of the underlying device. Among them, the control network communication adopts the current popular producer/consumer mode. The mode adopts multi-channel broadcast type, fixed-point transmission, which belongs to predetermined information. Each signal corresponds to a separate address, occupying a network node, and all nodes in the network are synchronized. The information throughput is large, the speed is fast, and the network efficiency is high; therefore, the control network has High-speed, highly deterministic and repeatable network, especially suitable for information transmission in complex applications with time-critical requirements, but the number of nodes in the Controlnet network is limited, the maximum cannot exceed 99, and the number of nodes exceeding the limit will occur. Unpredictable failures, not exceeding but too much will affect the network speed and cause network lag. Controlnet uses coaxial network cable or optical fiber as the medium. Relatively speaking, Controlnet is more stable than Siemens' Profibus network, easy to maintain, and helps to achieve seamless connection.

Devices that Can Build ControlNet

1.ControlLogix, PlantPAx, CompactLogix series

2. PC-based controller series

3. I/0 frame type and module type