ABSTRACT
ControlNet is an open industrial network protocol belonging to common industrial protocol (CIP) family. Presently it is supported by the Open DeviceNet Vendors Association, Inc. (ODVA). It is a high-speed deterministic network used for time-critical applications. It supports producer-consumer network model which allows data from a node to be multicast to all nodes connected in the network, i.e., synchronously. It results in increased efficiency and higher system performance. In peer-to-peer mode, it provides real-time control. It offers high throughput.
In ControlNet profile, only layer 5 of open systems interconnection (OSI) is absent. The physical layer of ControlNet is split into two: physical medium attachment (PMA) and physical layer signaling (PLS). PMA helps in delivering/accepting data to/from the bus to which the devices are attached. PLS is responsible for proper timing and also bit representation of data generated by the devices. It also acts as an interface to the next higher later—data link layer. Physical layer signaling uses Manchester coding with a bit rate of 5 Mbits/sec. The data link layer consists of medium access control (MAC) and logical link control (LLC).
