Ethernet is a familiar network standard. It was created by Xerox and jointly developed by Xerox, Intel and DEC. It is the most common communication protocol standard used in current local area networks, including standard Ethernet (10 Mbit/s), Fast Ethernet (100 Mbit/s) and 10G (10 Gbit/s) Ethernet.
PROFIBUS is an international, open, and manufacturer-independent fieldbus standard. PROFIBUS transmission speeds are selectable from 9.6 kbaud to 12 Mbaud, and all devices connected to the bus should be set to the same speed when the bus system is started. It is widely applicable to automation in manufacturing, process industries, and other fields such as building, transportation, and power systems. PROFIBUS is a fieldbus technology used for shop floor level monitoring and data communication and control at the field device level in factory automation. It enables distributed digital control and field communication networks from the field device level to the shop floor level monitoring, thus providing a feasible solution for achieving comprehensive factory automation and intelligent field devices.
PROFINET = PROFIbus + Ethernet. It transplants the PROFIbus master-slave structure to Ethernet. Therefore, PROFINET has a Controller and a Device, whose relationship can be simply compared to the PROFIbus Master and Slave. Of course, there are differences, but this correspondence helps in understanding. Furthermore, because PROFINET is based on Ethernet, it can have Ethernet topologies such as star, tree, and bus, while PROFIbus only has a bus topology. Therefore, PROFINET is a product of combining the PROFIbus master-slave structure with the Ethernet topology. Other features touted by Siemens, such as isochronism, are also present in Ethernet; however, PROFINET's Controller improves the accuracy of isochronism.
PROFINET is a new Ethernet communication system developed by Siemens and the PROFIbus User Association. PROFINET features communication capabilities between products from multiple manufacturers, automation and engineering modes, and is optimized for distributed intelligent automation systems. Its application results in significant savings in configuration and commissioning costs. PROFINET systems integrate with PROFIbus-based systems, providing protection for existing system investments. It can also integrate with other fieldbus systems.
PROFINET is an advanced communication system supporting distributed automation. In addition to communication functions, PROFINET includes specifications for distributed automation concepts based on a manufacturer-independent object and connection editor and an XML device description language. Ethernet TCP/IP is used for time-sensitive communication between intelligent devices. All time-sensitive real-time data is transmitted via standard PROFIbus DP technology, and data can be integrated into the PROFINET system from the PROFIbus DP network through a proxy. PROFINET is unique in that it uses existing IT standards and does not define its own proprietary industrial application protocols. Its object model is based on Microsoft's Component Object Model (COM) technology. Interactions between all distributed objects on the network use Microsoft's DCOM protocol and standard TCP and UDP protocols.
In the PROFINET concept, equipment and facilities are divided into technical modules, each comprising mechanical, electronic, and application software components. The application software for these components can be developed using dedicated programming tools and downloaded to the relevant controllers. This dedicated software must implement the PROFINET component software interface, enabling the export of PROFINET object definitions to XML. The XML file is used to input a manufacturer-independent PROFINET connection editor to generate PROFINET elements. The connection editor defines the exchange operations between PROFINET elements on the network. Finally, the connection information is downloaded to the PROFINET devices via Ethernet TCP-IP.
PROFINET (Real-time Ethernet) is based on industrial Ethernet and has excellent real-time performance. It can directly connect to field devices (using PROFINETIO). Using a modular design, PROFINET supports distributed automation control (PROFINETCBA, which is equivalent to communication between master stations).
After Ethernet was applied to industrial control applications, the modified Ethernet used in industrial settings became known as Industrial Ethernet. If you have ever used Siemens network cards CP343-1 or CP443-1 for communication, you may have encountered ISO or TCP connections. The TCP and ISO protocols used in these cases are those applied to Industrial Ethernet.
PROFINET is also a protocol within Siemens SIMATICNET, specifically a collection of protocols including real-time protocols such as PROFINET IORT, CBART, and IOIRT. Therefore, PROFINET cannot be compared to Industrial Ethernet; it's simply a real-time protocol running on Industrial Ethernet. However, some networks are often referred to as PROFINET networks because they utilize the PROFINET protocol.
PROFINET is based on Industrial Ethernet, while PROFIBUS is based on RS485 serial bus. Their protocols are completely different due to their different media and are unrelated. Both share excellent real-time performance because they use streamlined stack structures. Any development based on standard Ethernet can be directly applied to PROFINET networks. There are far more developers of Ethernet-based solutions worldwide than PROFIBUS developers, thus providing more resources for technological innovation.
For PROFIBUS, the maximum data transmission bandwidth is 12 Mbps, and for PROFINET, the data transmission bandwidth is 100 Mbps.
For PROFIBUS, data transmission is half-duplex, while for PROFINET, data transmission is full-duplex.
For PROFIBUS, the maximum consistent data size is 32 bytes, and for PROFINET, the maximum consistent data size is 254 bytes.
For PROFIBUS, the maximum user data size is 244 bytes, and for PROFINET, the maximum user data size is 1400 bytes.
For PROFIBUS, the maximum bus length for 12Mbps is 100m, and for PROFINET, the bus length between devices is 100m.
For PROFIBUS, configuration and diagnostics require a dedicated interface template, such as CP5512; for PROFINET, a standard Ethernet network card can be used.
For PROFIBUS, special tools are required for network diagnostics, while for PROFINET, IT-related tools can be used.
For PROFIBUS, the main faults on the bus are caused by bus termination resistor mismatch or poor grounding; for PROFINET, bus termination resistors are not required.
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