The rationale for the need to develop new technologies is that the industry is moving towards "Industry 4.0". An open network standard is required that can transmit data from devices to communication lines with the speed and flexibility of standard Ethernet and IP technologies. It is necessary to replace existing devices that typically use traditional industrial network infrastructures, for example, fieldbus fieldbus, which prevent the implementation of applications that use data streams intensively.
The application of Ethernet should smooth out the network industrial infrastructure of an industrial facility to eliminate the need for gateways and prepare industrial communications for the next generation of equipment that is more likely to use Ethernet instead of a fieldbus. Currently, hazardous production facilities are experiencing a shortage of data transmission technologies and the inability to use more real-time data at Ethernet speeds. This will be a key factor for switching to Ethernet. One of these necessary new technologies is to bring Ethernet to promising intelligent field devices in explosive zones. Intrinsically safe industrial Ethernet in the field areas of hazardous production facilities is simply a means to achieve the goals set in Industry 4.0. This will be a real turning point for industrial Ethernet at explosive production facilities, and it is very important to create error-resistant network connections for the most reliable IIoT communication system.
The definition of smart devices has changed over the past decades. Modern intelligent field devices are equipped with digital network interfaces, self-diagnosis of their work, remote configuration, primary information processing, various monitoring and control algorithms, data loggers and a wide range of other features. Promising field devices for IIoT will have advanced intelligence. Apparently, in the future, the devices will acquire several communication channels, each with a built-in security system, similar to a network router controlled via an Ethernet network. These channels will be managed using an IP address and server technology, thereby turning the equipment into a real data server. The high-speed transmission channel will be used to transmit the process variable (PV) to the control processor in real time and will have priority over the rest of the communication resources of the device. Other communication channels will be used to connect the device directly to applications such as process monitoring, equipment condition, environment, energy management, asset management, maintenance planning and advanced diagnostics. This direct connection will be carried out in parallel with the real-time control system, which will simplify the overall architecture of the automation and information system. Information from advanced intelligent devices will increasingly be sent via Ethernet, and the devices themselves, in turn, will be directly integrated into management or database servers, IT networks. Combining all these progressive solutions will lead to the emergence of truly intelligent components of the "Industrial Internet of Things" (IIoT), which will have better process management, higher efficiency, lower energy consumption, reduced downtime and improved quality. Advanced intelligent field devices are being transformed into Intelligent Remote Terminal Devices (iRTU), which blurs the very concepts of field layers, control and control.
With the development of the era of big data, the architecture of the "Industrial Internet of Things" (IIoT) will include cloud computing and intelligent remote endpoints (iRTU), which are dispersed geographically in a wide regional area. Examples are monitoring networks, industrial application systems in the extractive industry. Remote terminal devices (iRTU) can not only replace programmable logic controllers (PLC) and complete local tasks no less conscientiously, but also communicate with the master center via high-speed communication channels with predefined behavior. The transition of devices to industrial Ethernet will begin with the devices with the highest value. First of all, devices with a high level of data usage, such as analyzers and scanners, will undergo modernization. Intrinsically safe Ethernet technology cannot be directly implemented into previously installed field devices, but there are already the latest intrinsically safe Remote IO Ethernet/IP devices and intrinsically safe Remote IO Modbus RTU for communication with existing field devices. Therefore, it will be possible to gradually switch to a new technology by connecting outdated and new devices in the same network in a mixed, seamless scenario.
The use and widespread introduction of Ethernet in the automation of industrial processes has long been constrained by the requirements for explosion safety, in cases where the final device was installed in an explosive zone. Until now, installing Ethernet in hazardous areas has been a difficult task in terms of ensuring continuous operation under voltage and ensuring a fast, secure connection. The physical layer of Ethernet consists of a transmission medium (optical cable, twisted pair or wireless medium) and information encoding methods for each transmission rate. The use of wireless connectivity imposes significant limitations on mission-critical devices. In the case of "optics", for repair or maintenance, it is required to de-energize the network for a long time, which is unacceptable for most industries. The twisted pair solution of intrinsically safe industrial Ethernet is more acceptable for working with mission-critical devices. The speed of industrial Ethernet connection is also very important. Collisions (in network technologies, the overlap of two or more frames from stations trying to transmit a frame at the same time in a shared access transmission medium) and repeated attempts to transmit a frame are the reason that the message delivery time in an Ethernet network is not deterministic and its value increases sharply with increasing network congestion. The reason is that when collisions occur, network congestion increases due to attempts to retransmit the same frames. Therefore, it is theoretically possible that the device will never get access to the network. This situation was the main reason why the Ethernet network has not been used in industrial automation for a long time. This problem is solved, for example, with the help of industrial Ethernet network devices with a special technology for suppressing incoming traffic "Advanced Flow Control", when a network adapter that supports this standard, after receiving a command from the switch "Suspend transmission", stops transmitting frames, and after the command "Resume transmission" resumes it. However, in this case, the bandwidth can be significantly less if several devices are trying to connect through the switch to the same network device.