Types of PLC communication networks

Buses are divided into three types: 1. Fieldbus. Suitable for the control and diagnosis of process technologies. This is because in applications with high real-time requirements, fieldbuses can provide fast and reliable two-way communication between \"intelligent\" devices and systems. Such networks are designed specifically for information communication involving multiple floating-point variables, and include the status of each variable—all variables are sampled at the same rate. The transmission rate of fieldbuses is generally lower than that of device buses or sensor buses. For example, in the FF bus, such technologies also include function blocks developed to support standards for decentralized control at the field level. Profibus PA can also operate on existing instrument wiring and supports intrinsically safe operation. But it does not support the open functional blocks for decentralized on-site control. 2. Device bus: The design goal of the device bus is to meet the needs of multiple complex devices. Discrete operations of fast-moving devices typically require a communication speed with rapid response. This type of bus is commonly used in papermaking machines, packaging lines, and motor control centers. For example, two examples of device buses are DeviceNet and Profibus-DP—whose design goal was aimed at the discrete manufacturing industry, but they are now also used in process plants. 3. Sensor bus: The sensor bus is widely used in the discrete manufacturing industry. They are used in conjunction with proximity switches, buttons, motor starters, and other simple devices. The above scenarios are characterized by minimizing costs while only requiring the transmission of a small amount of information. The sensor bus is designed for \"bit-level\" communication applications, and is suitable for simple measurements and logical actions, such as turning a device on or off or indicating its on/off status. Such as: ASI bus, etc. Network topology: star, ring, daisy chain, etc. Ethernet is a type of network, not a structure.

I would like to ask whether MODBUS is better or PROFIBUS is better

In terms of transmission stability and distance, I think the Ethernet architecture is more reasonable.

I think PROFIBUS is fine... and most field devices also support PROFIBUS as a backup

Personally, I think Profibus is better; it seems more stable

I also want to know whether MODBUS is better or PROFIBUS. What are the differences between them and their advantages and disadvantages?/Thank you:D

MODBUS is a communication protocol, while PROFIBUS is a type of bus.

Profibus is a fieldbus communication protocol used for workshop-level monitoring in factory automation, as well as for data communication and control at the field device level. What the original poster wants to compare is the quality of fieldbus and Ethernet communication, right? A fieldbus is a fully digital, real-time, two-way, multi-station communication system used for interconnecting devices at the field level, as well as connecting field devices to control systems. In terms of both reliability and transmission distance, fieldbuses are superior. Modbus is a communication protocol primarily used in RS232/RS485 communications, and it does not belong to fieldbuses.

In terms of transmission speed, for long-distance transmission, MODBUS can only reach 37.4 KB/S (I might be mistaken; the error is less than 5 k), while PROFIBUS can reach 1.2 M.

Profibus is a bit better