How a Unified IOT Controller Can Simplify Smart Factory Installations

­The technologies underlying IoT devices could also benefit the industrial sector. This resulted in the proliferation of ‘The Industrial Internet of Things (IIoT)’ edge devices (sensors and actuators) using various wireless communications protocols. In theory, this flexibility should be a welcome development, but in practice, it creates unwanted headaches for smart factory planners. This article reviews some of the most widely adopted wireless technologies for industrial applications and discusses the challenges of integrating multiple wireless protocols in industrial facilities before showing how the features of a new software development kit (SDK) from Silicon Labs can greatly simplify future IIoT installations.

Wireless protocols in the IIoT

Many wireless communication protocols were developed because no single technology addresses all application requirements regarding speed, distance and reliability. Industrial applications are well-placed to benefit from the IIoT because they are simple. For example, some sensors only transmit readings periodically, meaning they have low bandwidth and power requirements. In addition, simple (and easily replaceable) binary input/output (I/O) ‘pushbutton’ switches still regularly feature on factory floors. Some of the widely used wireless protocols in the IIoT include:

●      Wi-Fi (802.11) is widely used because it offers high data transfer rates, is well established (and therefore widely available), and is compatible with multiple device types. It is suitable for applications where power consumption is not a primary concern and a reliable and high-bandwidth connection is necessary.

●      Bluetooth Low Energy (BLE)can be used for short-range communications between devices in IIoT applications. It is ideal for extending battery life in remote battery-powered sensors that are only required to transmit measurements periodically.

●      Zigbee (IEEE 802.15.4) is a low-power wireless communication protocol specifically designed for low data rate (1Mb/s) and low-power applications over short distances (10-100 meters). It is used in industrial automation wireless sensor networks and robotics control systems for robotics.

●      Z-Wave: Z-Wave is a low-power wireless protocol for home and industrial automation applications. It is reliable and enables long-range communication (up to 100 meters).IIoT applications for Z-wave include smart lighting, automatic gate opening, outdoor access controls (smart locks) and other security applications.

●      LoRaWAN (Long Range Wide Area Network): This is a long-range, low-power wireless protocol that connects devices over large distances. It suits IIoT applications requiring low data rates but with a wide geographical area, like environmental monitoring. Its high sensitivity means devices can still operate despite a weak LoRaWAN signal.

●      Narrow band Internet of Things: NB-IoT is a cellular-based technology designed for low-power, wide-area IoT applications. It provides better coverage than traditional cellular networks and is well-suited for deep indoor penetration applications.

●      Sigfox: Sigfox is an LPWAN (Low-Power Wide Area Network) technology enabling long-range (approximately 1- 3km) communication with low data rates. It is a lower-cost alternative to other wireless communication protocols. IIoT applications for Sigfox include asset management and smart metering.

Challenges in planning IIoT wireless networks

Well before the possible benefits of wireless communication for the industry were proposed, the sector was already overwhelmed by a plethora of proprietary wired network protocols. Various incompatible Fieldbus networks like Modbus and Profibus were followed by multiple industrial Ethernet-like Profinet, Ethernet/IP, and EtherCAT. These presented conundrums for factory planners in deciding which to adopt based on the availability of sensors and actuators to support them. Adding an array of wireless protocols to this scenario created an additional layer of complexity they didn’t need. While it’s clear that wireless sensors and actuators are easier to install than wired devices in pre-existing facilities (since they do not require additional communications cabling to connect to a process controller. However, they need planners to take the necessary time to understand their operation, at the physical and higher layers,  to identify the multiple gateways required to enable wireless devices to interface with existing wired infrastructure – a time-consuming task requiring specialized software skills that many smart factory planners do not possess. Furthermore, apart from individual gateways, each wireless technology requires a new application layer resulting in a disjointed ecosystem.

Unify SDK solves multi-protocol IIoT integrations.

The UnifySDK Unified IoT Controller (UIC) can address these problems by enabling the development of a single flexible, multiprotocol gateway/controller for IIoT devices using different wireless technologies. With the use of MQTT as its core protocol, Unify is simple to integrate with more or less any cloud backend, fairly little need for a specific cloud connectors. This software framework simplifies the developer's job by removing complex network control and network management elements related to gateway development in IIoT applications. It is an open, modular, and portable architecture based on ubiquitous lightweight MQTT technology.

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Figure 2: Unify UIC from Silicon Labs

With this common interface, complex behavioral details for wireless protocols like Z-wave, Zigbee and BLE, for example, are abstracted into a common API.  Placing this abstraction layer on both the cloud/industrial network and radio-facing sides enables a single future-proof gateway to which new protocols or application layers can be easily added. Supporting a new protocol requires adding a wireless stack based on the same MQTT-based high-level language without reworking connections and existing services. This centralized uniform MQTT framework decouples the high-level API used for monitoring and managing IIoT nodes from their perspective protocols and PHYs, so a cloud service can be developed to control sensors, for example, without having to understand the difference between Zigbee or Z-wave or any of the details of how those protocols or the wireless radio transmitter operate. A controller that speaks a uniform language facilitates the reuse of this high-level code. So, if a particular protocol is currently supported, adding devices working with a different protocol simply requires a new controller. Having a stable API means the new protocol operates the same way as the existing one. Similarly, adding devices using a different PHY makes no difference to the API, which only sees new nodes appearing on the network, oblivious to their physical layer and higher-level protocols. Unify SDK simplifies development and software maintenance for IIoT gateways and application processor-based end devices. This platform provides software sources, binary packages and a collection of reference designs for Raspberry Pi 4 to facilitate the easy development of an IIoT gateway based on the Unify architecture. The SDK currently supports BLE, Zigbee and Z-Wave, and it also offers bridge functionality for protocols that do not natively run Matter. Silicon Labs is currently working on supporting other protocols, but in the meantime, developers can add MQTT-based stacks for custom wireless applications, including those previously discussed.

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Figure 3: Unify SDK can simplify the IIoT

Conclusion

The IIoT is one of the critical enablers for smart factories. However, the requirement to add multiple gateways for sensors and actuators using various protocols creates a headache for factory planners already struggling to support wired installations. Silicon Labs’ UnifySDK offers a roadmap towards replacing these with a single gateway that has the ability to support multiple protocols, allowing devices to be seamlessly added to industrial networks irrespective of their wireless protocol or physical layer connections.

Silicon Labs