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This article mainly introduces what are the differences between profibus and modbus, the article is very detailed, has a certain reference value, interested friends must read it!

Difference: modbus is a serial communication protocol, which is widely used in the industrial field, and now it is also a common connection mode between industrial electronic devices, while profibus-DP is a communication protocol between device-level control systems and distributed Icord O.

Main differences:

First, the subject is different

1. Modbus: it is a serial communication protocol, which was published by Modicon Company in 1979 for communication using programmable logic controller (PLC). Modbus has become the industry standard of communication protocols in the industrial field, and is now a common connection mode between industrial electronic devices.

2. Profibus-DP: a communication protocol with high speed and low cost, which is used for device-level control system and distributed Iphamo. Together with PROFIBUS-PA and PROFIBUS-FMS, it forms the PROFIBUS standard.

Second, the characteristics of the agreement are different

1. Modbus: only 247 addresses can be processed on a data link, which limits the number of devices that can connect to the master site. There is only one host, and all communications are sent by him. The network can support as many as 247 remote slave controllers, but the actual number of slaves supported is determined by the communication device used.

2. Profibus-DP: used for high-speed data transmission at the field equipment level, the master station reads the input information of the slave station periodically and sends the output information to the slave station periodically. The bus cycle time must be shorter than the master station (PLC) program cycle time. In addition to periodic user data transmission, PROFIBUS-DP also provides aperiodic communication required by intelligent equipment for configuration, diagnosis and alarm processing.

Third, different transmission characteristics

1. Modbus: the protocol includes ASCII, RTU, TCP, etc., and does not specify the physical layer. This protocol defines the message structures that the controller can recognize and use, regardless of the network over which they communicate. The data communication adopts Maser/Slave mode. The Masterside sends out the data request message. After receiving the correct message, the Slave side can send the data to the Masterside to respond to the request.

2. Profibus-DP: the protocol clearly defines how the user data is transferred between the bus stations, but the meaning of the user data is specified in the PROFIBUS rules. Token transfer mode is adopted between PROFIBUS master stations, and master-slave mode is adopted between master stations and slave stations. The token passing program ensures that each master station gets bus access within a specified period of time.

These are all the contents of this article entitled "what are the differences between profibus and modbus". Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!

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