- By Andy Piatek, Ron Blow
- Smart Manufacturing (Industry 4.0)
Industrial-grade private wireless networks join wired solutions to support advanced applications.
Modern industrial and process automation systems consist of many subsystems and components, including CNC machines, robots, controllers, interfaces, sensors, actuators, and other production assets. To fulfill the manufacturing or processing requirements, these devices must communicate their state and exchange data. That is the function of industrial networks.
Early industrial networks did not have the need to carry large volumes of data and instead relied on arrays of relays and switches to communicate with motors and other load devices. Over time, the production and processing systems became more advanced and drove the development of complex communication protocols. Today, it is common to see a combination of various transmission methods, including serial, Ethernet, and wireless protocols.
In serial communication, data is transmitted sequentially bit by bit, which translates to very slow transmission speeds; the point-to-point RS-232 standard defined the rate at 1.492 Kbps for up to 15 m (50 ft). The improvement to RS-232 is the multipoint RS-485 standard, which provides communication for fieldbus protocols such as Modbus or Profibus. It delivers 10 Mbps and can support a cable length of up to 1,200 m (4,000 ft).
Ethernet, defined in IEEE 802.3, is commonly used for connecting devices in a wired local area network (LAN) and wide area network (WAN). It is the de facto standard for enterprise networks. Multiple Ethernet specifications define different cable options and speeds, but they all share the same data link format, allowing integration of nodes running different “flavors” of Ethernet.
The implementation of Ethernet for industrial automation is slightly different from what one typically sees in the enterprise space. Here are some of the differences:
- utilization of ruggedized switches, routers, and cables with special connectors to allow the network to function in harsh environments and operating conditions
- typical speeds range from 10 Mbps to 1 Gbps, with 100 Mbps being the most popular
- adaptation of a ring topology for redundancy and quick service restoration; star topology is mostly deployed on the office networks
- implementation of industrial Ethernet protocols, such as EtherNet/IP, Profinet, Modbus TCP/IP, and EtherCAT, to achieve deterministic performance for real-time, critical communication.
Ethernet allows for an integration of operational technology (OT) and information technology (IT) systems and can be a key enabler for innovative use cases such as the Industrial Internet of Things (IIoT).
Running traditional field wiring through an industrial facility can be expensive. It is not even possible in some cases. Wireless technology has multiple benefits over wired connections, including cost savings, quick and flexible deployment, and mobility for applications used by plant operators. Several wireless technologies, each suited to certain applications, can be found on the increasingly smart factory floor (figure). Wireless technologies deployed for industrial operations can be divided into three categories based on their role:
- for connecting sensors and field devices, e.g., LR-WPAN, BLE, LPWAN
- for connecting distant parts of the plant, e.g., Wi-Fi, LTE/5G
- for mobility applications used by field personnel, e.g., Wi-Fi, LTE/5G.
Low-Rate Wireless Personal Area Network (LR-WPAN), IEEE 802.15.4, is typically used for low-data-rate monitoring and control applications on devices with low power requirements. Examples of LR-WPANs are ISA-100.11a, WirelessHART, ZigBee, 6LoWPAN, and Thread. Each has advantages, with some offering self-organizing and self-healing mesh architecture and Advanced Encryption Standard (AES) data encryption.
Bluetooth Low Energy (BLE) operates at 2.4 GHz. It is mainly used for low-cost, short-range connectivity for battery-operated devices that do not require high bandwidth. BLE is well suited for connecting remote controls, handheld devices, locks, and smart sensors. Additional benefits of BLE are a near-real-time location tracking and 128-bit AES encryptions.
Low Power Wide Area Network (LPWAN) provides long-range communication at low data rates with very low power consumption (battery life is up to 10 years). It is well suited for machine-to-machine (M2M) communication. Typical applications include smart meters, pipeline monitoring, and various IoT-based solutions for smart agriculture and smart cities.
Wi-Fi, as defined by the IEEE 802.11 family of standards, is widely used by computers, mobile devices, and other devices to connect to the local area network and to the Internet through a wireless router. Wi-Fi operates at either the 2.4- or 5-GHz spectrum, and at 6 GHz for the newest Wi-Fi 6 standard. It offers high data rates up to 600 Mbps for 802.11n, 3.6 Gbps for 802.11ac, and 9.6 Gbps for 802.11ax. Those data rates are the theoretical rates. The real rates are about 50 percent less, but they are still very high for a wireless technology. Wi-Fi was not meant for battery-operated devices, and it is typically used for machine monitoring and connecting the plant floor to enterprise systems.
Both 4G/LTE and 5G have been standardized by the 3rd Generation Partnership Project (3GPP), which unites seven telecommunications standard development organizations (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). These standards cover cellular telecommunications technologies, including radio access, core network, and service capabilities, which provide a complete system description for mobile telecommunications. The 3GPP specifications also provide hooks for nonradio access to the core network, and for interworking with non-3GPP networks.
Why industrial connectivity is important now
Plant operators are looking for ways to improve operational efficiency, reduce costs, and increase overall equipment effectiveness through various Industry 4.0 initiatives. Industrial connectivity is the foundation for Industrial IoT solutions. It enables operators to get insights into their production assets to better understand their performance, improve efficiency, and avoid costly downtime. Asset-intensive industries are moving quickly to take advantage of these technologies.
Industrial-grade private wireless networks meet the demands of industry’s mission- and business-critical operational applications. Critical communications solutions based on industrial-grade private wireless offer many possibilities to power Industry 4.0 use cases in industrial sites, plants, campuses, and wide area networks. Use cases range from machine remote control to cloud robotics, process automation, predictive asset maintenance, assisted/autonomous vehicles, CCTV monitoring, and mission-critical push-to-talk and push-to-video, all on a single network infrastructure.
Trends in industrial connectivity
Recent research from Nokia and ABI Research reports that 74 percent of manufacturing decision makers surveyed plan to upgrade communications and control networks in the next two years to advance digital transformation and Industry 4.0. More than 90 percent are investigating the use of 4G/5G for their operations, and 84 percent of those considering 4G/5G will deploy their own local private wireless network in their manufacturing operations. Additional insights can be found in technology developments. Here are few examples:
Single-pair Ethernet (SPE). SPE offers faster and cheaper Ethernet connectivity with power over data lines (PoDL) to remotely power field devices. The IEEE P802.3cg 10BASE-T1L standard specifies full-duplex transmission over a single pair of conductors at 10 Mbps for up to 1000 m. SPE is much faster than fieldbus and can use the existing single twisted pair fieldbus cable runs—a huge savings.
IEEE 802.3ch supports up to 10 Gbps with a cable length of up to 15 m. SPE meets the requirements of the industrial Ethernet and will be able to support EtherNet/IP, HART-IP, OPC UA, Profinet, and other higher-level network protocols.
Time Sensitive Networking (TSN). The traditional IEEE 802 Ethernet standard is based on the best-effort principle and does not provide the level of determinism required by industrial systems. The transport of critical and time-sensitive control data requires reliable transmission with a defined latency. TSN is a collection of IEEE 802.1 standards developed to address the shortcomings of Ethernet; its main focus is on time synchronization, bounded low latency, reliability, and resource management. TSN allows time-sensitive, critical data to be transported together with best-effort traffic on the same network infrastructure without any concern that critical data gets delayed. Network convergence is possible due to time synchronization and prioritization of data streams implemented by TSN.
Emerging protocols. IoT Analytics cites five trends pushing industrial connectivity forward, and an important one is the development of communications protocols. “IO-Link, OPC UA and MQTT are emerging as the fastest growing I/O, OT and IT protocols, respectively, as vendors and end users alike look to capture richer industrial datasets more efficiently,” they say. “A key barrier preventing more widespread adoption of the OPC UA and MQTT protocols is the lack of widely adopted data structure standards.” Despite the challenges, industrial connectivity vendors have products that natively support these protocols.
Private LTE/5G. The need to constantly reinvent operations to optimize safety, sustainability, and efficiency has made a compelling case for digitalization and automation in the mining and oil and gas industries and elsewhere. Wi-Fi, WiMAX, and others were not designed for frequently changing environments that need permanent, pervasive, and predictable network coverage. They do not provide the necessary coverage, reliability, mobility, precision, or service prioritization.
Delivering the advanced applications of Industry 4.0 in today’s industrial spaces is really only possible with today’s 4G/LTE, 4.9G/LTE, and 5G cellular industrial wireless networks. More than 85 percent of digital applications can already run on 4.9 G today. Once the industrial ecosystem has fully developed, the upgrade to 5G will be straightforward.
Release 16 and Release 17 of 5G are bringing critical machine connectivity features, such as ultra-low latency and TSN, which are necessary for Industry 4.0 applications. 5G will bring significant benefits for private wireless, enabling most of the remaining 15 percent of applications not yet possible on private 4.9 G today: applications that need more bandwidth (ultra-high-definition video services) or ultra-low latency for real-time tele-remote control of robots and drones. The 5G release 18 standard, which is due in 2023, should bring the final piece of the puzzle with massive IoT connectivity—the successor to LTE-M and NB-IoT.
Industrial connectivity supports every Industry 4.0 advanced application and all aspects of the smart plant and smart factory. A private 5G network in particular is a critical enabler of IIoT technologies; it promises reliable, low latency connectivity with better performance, privacy, and levels of security. A private 5G network is the nervous system of any digital factory campus, and it is already showing how it enables machine-to-machine (M2M) communications, smart asset management, facility security, digital twins, and augmented worker applications. Transmitting data at 5G speeds is just the beginning.
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