Some knowledge about industrial real-time Ethernet PROFINET

What kind of intuitive impression does everyone have about the word "standard"? It is the same thing as the white paper - there are chapters and clauses, text and data, definitions and explanations. Indeed, the content of PROFINET's training course is nothing more than real-time communication, distributed field devices, motion control, distributed automation, network installation, security, process control, IT standards, etc., look like a piece of cake, explain esoteric, difficult to understand The appearance of an "old school" does not give a feeling of "new generation". So, the monks wanted to re-interpret PROFINET through a more popular method--diagram xxx or a picture to understand xxx--to make it more intimate and more grounded.

What is the use of PROFINET?

“Industry 4.0” is the hottest topic in the current manufacturing industry, so it is not embarrassing to talk about this topic with the peers. An important part of “Industry 4.0” is the wisdom factory. The communication between the factory assembly line equipment, whether it is the traditional wired connection or the advanced wireless connection and distributed control, can be realized through PROFINET. From a certain point of view, it can be said that PROFINET The role is these blue and red "connection lines." Do not underestimate these lines, these are not embroidery lines, but in the "connect smart world" - smart connections.

In the past, the robot is currently a very big thing. The communication network of the robot control system uses industrial Ethernet more and more. If the controller is the human brain, then the industrial Ethernet is the nervous system. Transmission of various sensing signals and action indications. The role of PROFINET is to make the communication network more able to meet the demanding requirements of motion control, so that the robot can do as the song sings, "I am more nervous, not afraid of not afraid of you."

PROFINET features

In the past few years, the engineers who have been to the Siemens booth of the Industry Fair have an impression that the “triangular” layered architecture of the factory automation communication network is the field level, the control level, and the management level from the bottom up. The most prominent feature of PROFINET is that it can transmit data such as process data, voice, and image through a network cable, connect different networks, and truly realize "one network after another."

The average person may not have an intuitive feeling of “a network after all” because the current factory network is running very well and there is no advantage in improving the experience. In fact, I’ll make an analogy and you feel it.

Let me report on the “dark curtain” of decoration. The hydropower reform (right picture above) is an important part of the renovation and is also the most profitable part of the decoration company. The hydropower reform needs to consider the separation of strong electricity (220V) and weak electricity (television, telephone, and network). The strong electricity part needs to select wires of different thicknesses. For example, the power cord of the air conditioner should be thicker, and the power cord of the lighting can be smaller. Because the power cords are of different thicknesses, and telephone lines, televisions, and network signal lines have to buy different types of cables, choosing a variety of wires is actually a place that people do not quite understand, so it is the most profitable place. If one day, such a technology emerges, and it is possible to use a standard, reliable, and transparently-priced circuit, even if the power is weak or the size of the current, it is better to supply water (just kidding). Save money! And PROFINET is such a technology for the factory communication network!

In recent years, there has been a trend in process control automation. As the cost of microprocessors and PCs has become lower and lower, the process automation of field devices, sensors, and actuators has changed from centralized control to distributed intelligence. These intelligent devices such as IOs, valves, and drivers are increasingly connected and communicated via Industrial Ethernet. PROFINET can integrate all these different levels of systems into a single, feature-rich network. PROFINET has communication capabilities, automation and engineering modes among multiple manufacturers' products and is optimized for distributed intelligent automation systems. Its application results can greatly save configuration and commissioning costs. The PROFINET system can integrate other bus systems including Profibus, providing protection for existing system investments.

Simply put, PROFINET = PROFIbus + etherNET, the master-slave structure of Profibus ported to Ethernet, so profinet will have Controller and Device, their relationship can simply correspond to Profibus Master and Slave, of course, there is a difference, But this correspondence can help understanding. In addition, since the profinet is based on Ethernet, it can have Ethernet star, tree, bus and other topologies, while the profibus only has the bus type. Therefore, profinet is the product of combining the master-slave structure of profibus with the topology of the ethernet. Other features such as isochronism and Siemens are in fact Ethernet. However, profinet can improve isochronism because of the control unit such as Controller. Accuracy only.

PROFINET is a new Ethernet communication system developed by Siemens and the Profibus Users Association. PROFINET has communication capabilities between multiple manufacturers' products, automation and engineering modes, and is optimized for distributed intelligent automation systems. Its application results can greatly save configuration and commissioning costs. The PROFINET system integrates Profibus-based systems and provides protection for existing system investments. It can also integrate other fieldbus systems.

PROFINET is an advanced communication system that supports distributed automation. In addition to communication functions, PROFINET also includes specifications for distributed automation concepts, which are based on the manufacturer-independent object and connection editor and the XML device description language. Ethernet TCP/IP is used for less time-critical communications between smart devices. All time-critical, real-time data is transmitted via standard Profibus DP technology. Data can be integrated into PROFINET systems via Profibus DP networks. PROFINET is the only bus that uses existing IT standards and does not define its proprietary industrial application protocol. Its object model is based on Microsoft Corp.'s Component Object Model (COM) technology. For the interaction between all distributed objects on the network, Microsoft's DCOM protocol and standard TCP and UDP protocols are used.

In the PROFINET concept, equipment and plants are divided into technology modules, each of which includes mechanical, electronic and application software. The application software for these components can be developed using a dedicated programming tool and downloaded into the relevant controller. These dedicated software must implement the PROFINET component software interface and be able to export PROFINET object definitions as XML languages. The XML file is used to enter the 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 via Ethernet TCP-IP to the PROFINET device.

PROFINET (real-time Ethernet) is based on Industrial Ethernet and has a very good real-time nature. It can be connected directly to field devices (using PROFINET IO), using componentized designs, and PROFINET supports distributed automation (PROFINET CBA, equivalent to the master station). Inter-communication).

After Ethernet is applied to industrial control applications, Ethernet that has been used in industrial sites has become an industrial Ethernet. If you have ever used a Siemens network card CP343-1 or CP443-1 to communicate, you may have applied ISO or TCP connections. The TCP and ISO that are used in this way are the protocols applied to Industrial Ethernet.

PROFINET is also a protocol in Siemens SIMATIC NET, specifically a collection of many protocols, including real-time protocols such as PROFINET IO RT, CBA RT, IO IRT, and so on. Therefore, PROFINET and industrial Ethernet cannot be compared. It can only be said that PROFINET is a real-time protocol running on industrial Ethernet. However, it is often said that some networks are PROFINET networks. This is because the PROFINET protocol is used on this network.