How to implement wireless sensor networks for difficult industrial settings
Pairing low-power wide area network (LPWAN) and Bluetooth low energy (BLE) networks allows the enterprise Internet of Things (EIoT) to connect wirelessly to remote locations.
Some of the most interesting and impactful implementations of Enterprise Internet of Things (EIoT) technology are in industrial settings, where wireless sensor networks and controls enable organizations to monitor and manage machinery in ways that have never been possible before. Wireless sensors that operate on a small battery—free from hardwiring—can be located within industrial settings in spots that were not feasible with prior generations of industrial sensors and controls.
An enterprise-class version of Internet of Things (IoT) technology-EIoT-has enhanced reliability, security, and comprehensive interoperability to address the stringent requirements of wireless implementations for industries such as manufacturing, health care, financial services and others. EIoT addresses these needs with technical features and design elements that far surpass those of traditional IoT used for less stringent consumer or commercial applications.
Industrial EIoT challenges
EIoT-enabled sensors and controls can go nearly anywhere within a given industrial environment, but until now there has been a catch. Not every industrial application has been ideal for going wireless because IoT deployments have two basic elements:
- Wirelessly-connected network of devices, which is installed with a series of sensors and controls linked with a short-range, low-power technology
- The network of IoT sensors needs to collectively communicate with other machines, controllers, and other parts of the network over a longer range of distance.
The ability to reliably communicate over a long distance is often a significant obstacle in industrial settings for a very simple reason: telecommunications connectivity via wire lines or cell tower signals is not always available at sites where industrial equipment is located. Even when connectivity is available, the cost of using cellular service just to deliver a few packets of sensor data at a time does not make a lot of sense-financially or technically. In addition, there are often similar issues when it comes to utility power, which may be hard to come by in remote locations where the equipment or infrastructure is not powered (for example, holding tanks).
Despite the ubiquity of connectivity in populated areas, some areas do not have reliable wireless telecommunication service. That is often very true when it comes to rural and remote locations for industrial equipment, such as remotely located oil/gas/pipeline machinery, water/wastewater systems that are far from metropolitan areas, holding tanks and pumps, and other applications. These sites also are often located far from the nearest technician who can drop by to check on equipment. It is not uncommon for onsite visits to take a full day for an engineer, or even a multi-day trip when visiting several remote sites. Often, finding workers to operate in these remote locations is difficult. EIoT-enabled sensors and controls are equally rare in remote settings, and in these settings low-power wide area networks (LPWAN) can help.
Wireless EIoT: BLE, LPWAN
The most widely used, short-range wireless technology in EIoT deployments is Bluetooth low energy (BLE; also known as Bluetooth Smart). The biggest reason for BLE’s popularity for EIoT is its power efficiency, which allows sensors and controls to operate for extended periods on a small battery. It manages sleep cycles and active cycles to conserve energy while meeting the data collection and reporting for certain applications. BLE is also widely used because of its radio frequency (RF) signal strength, which performs well even in complex environments with RF noise, computing signals, and physical obstructions—all of which are common in industrial settings.
BLE is the core short-range technology for many industrial EIoT projects that are implemented or in the design phase, but a network of BLE-enabled devices must have a way to relay data and receive instructions over distance. The reliance on traditional telecommunications infrastructure (which enables that bi-directional communication via Wi-Fi or cell signal) has put growth limitations on these sensor and control networks, which is why a complementary, long-range technology is so important. By combining BLE with the ultra-long range and low-energy capabilities of LoRa (from the LoRa Alliance, which announced plans to form in January), companies no longer have to limit EIoT deployments to locations where telecommunications and power infrastructure is immediately available. This opens up an entirely new geography for IoT implementations.
The LoRa wide area network protocol often is referred to as a LPWAN because it provides secure, bi-directional data transfer and communications with IoT networks over long distances for years without a battery change. It can send and receive signals up to 10 miles, and repeaters can extend that distance to hundreds of miles if needed. When LoRa is paired with short-range BLE technology in one integrated solution, the geographic restrictions that previously existed for EIoT implementations can be mitigated in a way that makes it possible for these low-power, short-range device networks to go nearly anywhere without the need to build a telecommunications infrastructure onsite. For sites where cell service is available but expensive because of the lack of competition in remote locations, LoRa and BLE make EIoT implementations more cost-effective. Previously, they were not due to the high cost of network fees when a cellular connection was needed to be used.
LoRa technology has many benefits for IoT applications due to its cost-effective specifications and capabilities including the following:
- It works well for battery-powered networks of IoT devices because, like BLE, it is also an ultra-low-power technology that can operate on a battery for an extended period of time and requires infrequent maintenance.
- The nodes are inexpensive and allow companies to bypass the high cost of cellular data fees or fiber/copper installation, which removes a major cost barrier to remote locations and means zero ongoing data charges.
- It works well with device networks located indoors, including in difficult industrial environments, which might otherwise present difficult challenges to other technologies.
- LoRa is highly scalable and interoperable, supporting up to a million nodes and compatible with public and private networks for data backhaul and bi-directional communications.
The tradeoff for using a low-power, ultra-long-range technology like LoRa is throughput, which makes it a poor fit for applications that require streamed data. But this limitation does not come into play with a wide range of IoT applications where small batches of event data are being delivered.
While other emerging LPWAN technologies have promise for addressing this long-range backhaul aspect of IoT implementations, LoRa offers bi-directional communications, immunity to interference, and large data payloads needed for IoT deployments.
Using LoRa, BLE technologies for EIoT networks
LoRa’s potential becomes apparent once it is paired with a technology like BLE. Together, they provide a set of short-range and long-range ultra-low-power wireless capabilities that expand the possibilities for EIoT networks. In urban areas, for example, an entire metropolitan area could be covered with just a few LoRaWAN gateways that serve as the backbone for BLE sensor networks that do not rely on traditional telecommunications infrastructure. In this way, LoRa and BLE lowers a number of barriers to expand IoT in populated areas like cities and towns, which would be significant because it provides a foundation for waves of creative IoT applications. However, the most dramatic impact of LoRA and BLE is giving wireless sensors and controls and other devices the ability to be installed anywhere.
BLE makes that possible by allowing wireless devices to be squeezed in any physical location. BLE also allows those devices to work together in an integrated, short-range network that is controllable from, for example, smartphones or tablets that serve as remote wireless displays. LoRa builds on BLE’s mobile capabilities by serving as a relay that can send and receive data over very long ranges that can be extended with simple gateways to pass the signals along. BLE makes EIoT possible in even the smallest corner of a facility, and LoRa makes EIoT possible on any spot on the map. This will significantly speed up the IoT revolution.
To illustrate what is possible when LoRa and BLE are paired, an application note discusses how to use a wireless temperature sensor to gather information from a piece of equipment. BLE sensors collect temperature data, a LoRA and BLE module can then (Laird’s RM1xx module) forward the information over a long-distance LoRaWAN network to be processed. It blazes an entirely new trail for this kind of sensor project because of how LoRa and BLE unlocks the ability to transfer data over much further distances, how it eliminates many of the most challenging aspects of deploying IoT, and how it represents a simple style of programming due to the pre-built components that are part of the module.
The promise of BLE is that sensors for temperature, moisture, vibration, liquid level, flow, and pressure valve controls can go anywhere, and that becomes literally, geographically true when it is combined with LoRa.
The pairing of LoRa and BLE is enabling EIoT networks to go beyond its previous limits technically and geographically. In doing so, this combination of technologies is opening up a new galaxy of exciting, new wireless possibilities to explore for industrial applications.
Zach Hogya is the director of software engineering at Laird and Jonathan Kaye is the director of product management of connectivity solutions at Laird. Edited by Emily Guenther, associate content manager, Control Engineering, CFE Media, firstname.lastname@example.org.
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About the Authors: Jonathan Kaye and Zach Hogya are senior members of Laird’s Connectivity Solutions Business Unit, which provides a full range of modules and other solutions that simplify the process of using wireless technology. Laird is a global leader in wireless technologies, embedded, pre-certified wireless modules and design services that are making the next generation of connected smart products possible. Kaye has nearly 20 years of experience in the embedded wireless and product design field, including positions at EZURiO and Lever Technology before joining Laird 8 years ago. Hogya has more than 20 years of experience in software design for wireless products, including a long tenure at AeroComm Wireless before joining Laird 9 years ago. Kaye and Hogya can be reached at email@example.com and firstname.lastname@example.org.
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