Industrial wireless technology is another hotspot technology in the field of industrial control after fieldbus. It is a revolutionary technology to reduce the cost of industrial measurement and control systems and improve the application range of industrial measurement and control systems. It is a new growth point for industrial automation products in the future. Industrial wireless technology is an emerging wireless communication technology for short-range and low-rate information interaction between devices in the 21st century. It is suitable for use in harsh industrial field environments. It has strong anti-jamming capability, ultra-low power consumption, real-time communication and other technical features.
Currently known wireless technologies are ZigBee, Wireless LAN (WiFi), Bluetooth (Blue-tooth), Ultra Wideband (UWB) and so on. However, due to limitations of their own protocols (such as transmission power, security level, anti-interference, etc.), they are usually used in consumer electronics and are not suitable for complex industrial site environments. Its characteristics are shown in Table 1:
Table 1 Comparison of common wireless communication protocols
At present, three major international standards have been formed in the field of industrial wireless technology, namely the WirelessHART standard issued by the HART Foundation, the ISA100.11a standard issued by the ISA International Automation Association (formerly the American Instrument and Control Association), and the WIA-PA independently developed by China. And WIA-FA standards.
Technical introduction
WirelessHART
The WirelessHART standard was released in September 2007 by the HART Communication Foundation and is the first open interoperable wireless communication standard designed specifically for the process industry to meet the reliable, robust, and secure wireless communication methods of industrial plants. Urgent needs. As part of the HART7 specification, in addition to maintaining the capabilities of existing HART devices, commands and tools, it adds the wireless capabilities of the HART protocol. In April 2010, the International Electrotechnical Commission approved the release of the fully internationalized WirelessHART standard IEC 62591 (Ed.1.0), the first international standard for wireless sensor networks in the field of process automation. The network uses the radio IEEE802.15.4 standard operating in the 2.4 GHz band, using direct sequence spread spectrum (DSSS), communication security and reliable channel hopping, time division multiple access (TDMA) synchronization, and inter-device extended control communication on the network ( Technologies such as Latency-controlled Communications, the WirelessHART standard protocol is mainly used in the field of factory automation and process automation to make up for the vacancy in the industrial wireless communication market with high reliability, low power consumption and low cost.
ISA100.11a
ISA has started the development of the industrial wireless standard ISA100.11a since 2005. It has been approved by the International Electrotechnical Commission (IEC) in September 2014 and has become the official international standard, the standard number IEC 62734. China's Chongqing University of Posts and Telecommunications as a core unit also participated in the formulation of the standard. ISA 100.11a is the first open family of standards for a variety of industrial applications. The industrial wireless devices defined by the ISA100.11a standard include field automation devices such as sensors, actuators, and wireless handheld devices. The main contents include industrial wireless network architecture, coexistence, robustness, and interoperability with wired field networks. The ISA100.11a standard addresses the coexistence of other short-range wireless networks and the reliability and determinism of wireless communications. Its core technologies include precise time synchronization, adaptive hopping, deterministic scheduling, and data links. Layer subnet routing technology and security management scheme, etc., and has the characteristics of reliable, accurate, real-time, low-power data transmission.
WIA
WIA technology is a high-reliability, ultra-low-power intelligent multi-hop wireless sensor network technology that provides a self-organizing and self-healing intelligent Mesh network routing mechanism that can maintain dynamic changes in application conditions and environments. High reliability and strong stability of network performance. At the same time, around the combination of semantic digital factory modeling and dynamic services, two IEC international standards and product systems, WIA-PA and WIA-FA, were developed, and interoperability interfaces between protocols, software and systems were opened.
---WIA-PA
WIA-PA is a practically validated wireless communication network protocol suitable for complex industrial environments. Its comprehensive flexibility in time (time division multiple access TDMA), frequency (ingenious FHSS frequency hopping mechanism) and spatial (reliable path transmission based on mesh and star hybrid network topology) makes this relatively simple but A very effective protocol with embedded self-organization and self-healing capabilities greatly reduces the complexity of the installation and ensures long-term and predictable performance of the wireless network.
WIA-PA officially became the IEC 62601 international standard in 2011.
---WIA-FA
WIA-FA technology is a set of factory automation wireless data transmission solutions specially developed for high real-time and high reliability requirements of factory automation. It is suitable for industrial wireless local area network with high speed and reliability requirements for factory automation. Wireless data transmission. The wireless system can make the workshop more clean and tidy, eliminate the danger of cables smashing and entanglement in the workshop, make the working environment of the workshop safer, have the advantages of low cost, easy to use, easy maintenance, etc. The important enabling technology of online reconfigurability will promote the transformation and upgrading of China's manufacturing industry.
A few days ago, WIA-FA officially became the International Electrotechnical Commission (IEC) standard (IEC 62948).
The experts summed up the current situation in one sentence: industrial wireless, three-legged.
Industrial wireless technology comparison
Currently, WirelessHART, ISA100.11a and WIA are the three international industrial wireless standards with their own advantages and features.
Table 2 Comparison of performance of three protocols
The core technologies of industrial wireless technology include time synchronization, deterministic scheduling, hopping channels, routing and security technologies. Table 2 compares and analyzes the three standards from the physical layer, data link layer, and network layer. It can be seen that the three standards have similar characteristics. The standard protocol architecture follows the OSI model and both refer to IEEE802. 15.4 as a physical layer standard.
At present, the WirelessHART standard has been developed with a large number of network devices and application devices. More than 26 million HART devices are already in use worldwide. Users have certain HART training and experience. Familiar with the WirelessHART wireless protocol requires only minor changes. . Emerson has introduced HART-compliant automation products (such as wireless adapters) and WirelessHART instruments, gateways, and put them into use. ABB, E+H, P+F and other instrumentation and field device providers are actively introducing products. Bomicro has developed the first WirelessHART module and gateway in China, and has been successfully applied and good customer feedback. The WirelessHART adapter is also under development. ISA100.11a has also been adopted and deployed by many European and American companies. It has been widely recognized in the industrial wireless market. The two giants Yokogawa and Honeywell have developed ISA100.11a. Scale system solutions. WIA-PA technology has been applied in metallurgy, petrochemical and other fields, and has been recognized by users. WIA-FA is used to realize wireless network technology between high-security, high-reliability and hard real-time information exchange between factory automation equipment such as sensors, transmitters and actuators. It can be widely used in intelligent upgrade of discrete manufacturing equipment.
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