DCS network topology

DCS network topologies are generally of a bus type. Personal opinion

1 Star Topology (1) A star topology consists of a central node and various stations connected to this node via point-to-point links. The main switching methods used in star topologies are packet switching and circuit switching, with circuit switching being more common. Most existing information networks for data processing and voice communication use this topology structure; modern PBX systems are typical examples of star topology. (2) Advantages and disadvantages of star topology: a. Easy to service; b. Each connection is made to only one device; c. Does not affect the entire network; d. Enables centralized control and fault diagnosis; e. Simple access protocols. The disadvantages include: I. Cable length and installation requirements; II. Difficulty in expansion; III. Dependence on the central node. 2 Bus Topology (1) Definition of bus topology: A topology in which a single transmission line is used as the medium for data transfer, with all nodes connected to this transmission line through appropriate hardware interfaces. (2) Advantages of bus topology: a. Short cable lengths, making wiring easier； b. High reliability ； c. Easy to expand. (3) Disadvantages of bus topology: a. Difficult fault diagnosis ； b. Repeater configuration: Expansion is carried out based on the main bus; repeaters can be used, and reconfiguration is required, including cutting the cable length and adjusting the terminators. c. Since the stations connected to the bus need to have medium access control capabilities, the terminals must be intelligent. 3 Ring Topology (1) Definition of ring topology: A network topology structure that consists of a closed loop formed by repeaters and point-to-point links connecting those repeaters. (2) Advantages of ring topology: a. Short cable lengths; b. No need for junction boxes; c. Suitable for fiber optics. (3) Disadvantages of ring topology: a. A failure at any node can cause a failure throughout the entire network ； b. Difficult to diagnose faults ； c. The network is not easy to reconfigure ； d. The topology affects the access protocol. 4 Tree Topology (1) Definition: Evolved from the bus topology; it has the shape of an inverted tree, with a root at the top that has branches, and each of these branches can further give rise to sub-branches. (2) Advantages: a. Easy to expand ； b. Fault isolation is easy. (3) Disadvantages: It relies too heavily on the root; if the root fails, the entire network cannot function properly. 5 Star-ring topology (1) Definition: A network topology structure composed of a set of connected hubs arranged in a ring, combining the advantages of both star topology and ring topology. (2) Advantages: a. Easy fault diagnosis and isolation ； b. Easy to expand ； c. Easy to install cables. (3) Disadvantages: a. Requires an intelligent concentrator; b. Cable installation issues

The network architecture of the x dps-400 system at Shanghai Xinhua is of the bus type. It is divided into Network A and Network B; both are real-time networks that transmit real-time data, and they represent the networks through which the HMI communicates with the main control DPU (the main controller). The two networks are identical, which helps to prevent any disruption in the system’s normal operation in the event that one of them fails. Operator stations typically have three network cards: in addition to networks A and B, there is also a network C, which is used by the operator station to send data to external systems, such as the RMIS network. This communication is usually one-way, allowing only data to be sent rather than received, thereby ensuring network security.