As a key equipment in industrial network architecture, industrial switches need to meet strict industrial environment requirements, and their core features include:
High reliability: Adopting redundant design (such as power redundancy and link redundancy), supporting wide temperature range (-40 ℃~85 ℃), dust prevention, earthquake resistance, and electromagnetic interference prevention, ensuring stable operation in harsh scenarios such as factories, mines, and transportation hubs.
Strong real-time performance: Equipped with QoS (Quality of Service) management function, it can prioritize different types of data traffic, ensuring the priority transmission of information with high real-time requirements such as industrial control instructions and sensor data, reducing latency and packet loss.
Protocol compatibility: Supports multiple industrial communication protocols, can adapt to devices and systems from different vendors, and achieve seamless connection of heterogeneous networks.
High security: Integrated firewall, access control, data encryption and other security mechanisms to resist viruses, malicious attacks and data leakage risks in industrial networks.
Common industrial communication protocols and their analysis
In the industrial field, switches need to support diverse communication protocols to meet the interconnection needs of different devices. The following are several mainstream protocols:
（1） Fieldbus protocol
The fieldbus protocol is the core of the industrial control underlying network, used to connect field devices (such as PLCs, sensors, actuators) and achieve short distance, high real-time data transmission.
PROFINET
Application scenario: Widely used in automation systems of brands such as Siemens, suitable for the fields of factory automation and process automation.
Features: Based on Ethernet technology, it integrates real-time communication, distributed clock synchronization, and standardized diagnostic functions, with a transmission rate of up to 100Mbps~1Gbps. Supports equal time real-time (IRT) mode for time sensitive motion control scenarios such as robots and CNC machines.
EtherCAT (Ethernet Control Automation Technology)
Application scenarios: Commonly used in high-performance automation fields, such as packaging machinery, printing equipment, and automotive manufacturing production lines.
Features: Adopting a master-slave architecture, the data transmission efficiency is extremely high. One master station can connect up to 65535 slave stations, with a transmission delay of less than 100 microseconds. Slave devices can achieve protocol processing without the need for a CPU, reducing hardware costs.
Modbus
Application scenario: It has a high popularity in industrial instruments, frequency converters, valves and other equipment, and is suitable for simple point-to-point communication or small networks.
Features: Divided into two modes: Modbus RTU (based on serial port) and Modbus TCP (based on Ethernet). The protocol is simple and easy to implement, with strong openness, but relatively weak real-time performance, and is commonly used in non time sensitive monitoring and data collection scenarios.
（2） Industrial Ethernet Protocol
The industrial Ethernet protocol optimizes real-time performance and reliability on the basis of traditional Ethernet, becoming the mainstream solution for industrial networks.
EtherNet/IP
Application scenario: The core protocol of Rockwell Automation (Allen Bradley) is applicable to the fields of discrete manufacturing, process control, and building automation.
Features: Based on TCP/IP and UDP/IP protocols, it supports explicit messages (for non real time data exchange) and implicit messages (for real-time I/O data transmission). Realize interoperability between devices through CIP (Common Industrial Protocol) and be compatible with multiple network topologies.
Powerlink
Application scenario: Mainly used in motion control fields that require high-precision synchronization, such as electronic manufacturing equipment and semiconductor production lines.
Features: Adopting a time triggered mechanism, ensuring real-time performance through precise clock synchronization (synchronization error less than 1 microsecond). High data transmission efficiency, supporting distributed clock and redundancy management, can build highly reliable industrial networks.
Sercos III (Serial Real time Communication System)
Application scenarios: High end machine tools, robots, printing machinery, and other applications that require extremely high real-time and synchronization.
Features: Based on Ethernet technology, the transmission rate can reach 1Gbps, and the synchronization accuracy is better than 1 microsecond. Support circular topology structure, with fast reconstruction capability. When a node in the network fails, topology switching can be completed in microseconds to ensure continuous system operation.
（3） Specialized Industry Agreement
Some industries have formed dedicated communication protocols due to special needs, and industrial switches need to provide targeted support.
DNP3 (Distributed Network Protocol 3.0)
Application scenarios: SCADA (Data Acquisition and Monitoring) systems for power systems, smart grids, and substation automation.
Features: Designed specifically for the power industry, it has strong anti-interference ability and safety, and supports functions such as telemetry, remote signaling, and remote control. The protocol adopts a hierarchical structure and can adapt to both wide area network and local area network environments, meeting the long-distance communication needs of power equipment.
OPC UA (Open Platform Communication Unified Architecture)
Application scenarios: Industrial Internet of Things (IIoT), cross platform data integration and interaction in intelligent manufacturing, such as uploading on-site device data to cloud platforms or enterprise management systems.
Features: Based on service-oriented architecture (SOA), it has compatibility across operating systems and programming languages. Supporting data modeling, secure authentication, and encrypted transmission, it enables end-to-end communication from sensors to the cloud, and is one of the important protocols for industrial digital transformation.
3、 Key factors in protocol selection
The protocol support capability of industrial switches directly affects the efficiency and stability of system integration, and users need to consider comprehensively when selecting:
Device compatibility: Ensure that the switch supports the protocols used by on-site devices and control systems to avoid "protocol islands".
Real time requirements: For scenarios such as motion control and high-speed production lines, prioritize protocols with strong real-time capabilities such as EtherCAT and Powerlink; For data monitoring and management applications, protocols such as Modbus TCP and OPC UA can be used.
Network scale: Small systems can use simple protocols such as Modbus and PROFINET; For large and complex networks, protocols such as EtherNet/IP and Sercos III that support large-scale nodes and redundant topologies need to be considered.
Future scalability: With the development of industrial Internet, switches supporting OPC UA and other emerging protocols have more upgrade potential, which can meet the long-term needs of digital factories.
Industrial switches become a bridge for the interconnection and intercommunication of industrial equipment by being compatible with diverse communication protocols. With the advancement of Industry 4.0 and intelligent manufacturing, the trend of protocol standardization and integration will become more obvious. In the future, industrial switches need to accelerate the upgrading to industrial Internet protocols while supporting traditional protocols, so as to provide more powerful support for the network architecture of intelligent factories.