Internet of Things Catch here

Wireless standards in IIoT applications: key considerations from field to system level

By Bernd Hantsche, director of product marketing Embedded and Wireless at Rutronik


he advent of the Industrial Internet of Things (IIoT) has led to the proliferation of standards for wireless data transmission. So, how do you select the most appropriate standard for the application?

This article offers useful guidance on how to integrate wireless infrastructures into IIoT applications, from the production line through to system level.

Field level 1: the production line Wireless data transmission starts from the sensors and actuators at the heart of production lines. These edge devices harvest energy from ambient light or heat and convert it into electrical power to transmit data packets over short distances. There are different wireless network options available here.

A compatible EnOcean module combination enables the energy harvesting process with ZigBee.

Bluetooth enables straightforward P2P connections or interaction with a smart phone, tablet or laptop, and is also fully self-powered.

Field level 2: the factory Sensors or actuators, connected to a gateway, hub, or edge computer, are virtually maintenance free and self-sufficient. But this approach has its limitations in larger and more complex networks at a factory level. Each wireless node must be permanently on to receive incoming data packets and process them immediately, requiring a permanent and intense energy supply. This is where wireless standards such as Bluetooth Mesh, Wi-Fi Mesh and ANT Blaze, ZigBee, and Threat come in.

While Wi-Fi Mesh operates with virtually no power supply, all the other mesh systems can operate for months on one battery charge.

18 October 2020

Unrouted data flow is generally the best choice factory-wide networks, as it ensures rapid reaction and throughput times. Smartphones and similar devices can be integrated easily, with no router required.

Field level 3: transshipment points Long-range wireless becomes necessary at transshipment points such as logistics centres, railway stations and ports. In most central European countries, LoRa has become one of the most popular wireless technologies using public and license-free ISM bands.

In France and the Netherlands, Sigfox is generally the go-to technology. The network in most countries is now expanding with the deployment of low- power mobile wireless technologies such as LTE-M for tracking applications. LTEM1 transceivers are often combined with a GNSS (Global Navigation Satellite System) within a single housing to enable location/motion tracking. Today, there are various GNSS alternatives to GPS such as Russia’s Glonassand, China’s Beidou and Europe’s Galileo.

Galileo is ahead of the curve in terms of free use of layer 1 data, making greater tracking accuracy available free of charge. And it is the only system to provide an authentication function, ensuring that the received signals do not originate from a counterfeit transmitting station. Generally, installing multiple systems in parallel is the best option; in this way the most recent multi-GNNS receivers work faster, more efficiently and accurately. It is important to be ready for future changes and react accordingly if one of the systems fails.

Process level

The data collected at the field-level sensor is often raw. Preliminary processing extracts

Components in Electronics

meaningful information from it, enabling users to compare several field data in parallel. This process is a computing intensive, requiring heavier-duty x86-based systems. This is where Wi-Fi 6 comes in.

Wi-Fi 6 is not just faster than the previous versions; it enables better connection managements. Another benefit is its improved frequency assignment with the upcoming 5G network.

System level

Local circumstances such as the size of the manufacturing site or the operational frequency plan will determine the choice of technologies at a system level.

Wi-Fi 6 may be the best choice for smaller dynamic operations. Larger companies with very static installations may want to consider a cabled solution. But, as soon as 5G becomes widely available and affordable, it may become necessary to rethink these installations too.

Operative level

As the data tends to be heavily condensed at the field and process levels, conventional LTE is normally enough to cope with the data throughput and latency periods – even in major international corporations.

Power consumption and the modem are negligible costs considering that the computers always operate from the mains, and only a very few LTE modems or LTE routers are deployed.

Different solutions from different manufacturers such as PC cards, external modems and routers can be combined, for example, a server may be configured with an LTE modem and a Wi-Fi 6 card.

The future of wireless Building upon its success in consumer smartphones, 13.56 MHz technology is now becoming more and more popular in industrial applications. It enables secure exchanges between active reader and passive transponder as well as between two active readers. It is compatible with almost all modern tablets and smartphones, enabling the use of relatively affordable, standard hardware.

Instead, the use of RFID for longer distances or to scan several transponders at once requires a 2.4 GHz band based on Bluetooth or a similar proprietary wireless protocol. The ANT wireless protocol is also becoming a popular choice. It is a great fit for applications where neither fixed cabling nor energy harvesting are available, and even affordable wireless connections such as BLE

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