Low-power radio options for harsh industrial environments

In Europe, analysts expect that figure to reach $41.6 billion by 2025, with manufacturing, energy, and utilities among the key growth sectors.

The need to reduce installation costs and increase operational flexibility is fuelling this transition. However, deploying wireless technologies in harsh industrial environments presents unique challenges.

Here, Dunstan Power, Director, ByteSnap Design explores the main low-power radio options available for such settings, covering their advantages, challenges, and best practices for implementation.

Key challenges in industrial environments

Industrial environments pose several challenges that wireless technologies must overcome:

• Wide temperature ranges: devices must function consistently across temperatures from -40 to +85°C, a range that poses challenges for batteries due to efficiency losses or failures at extreme temperatures
• Electromagnetic Interference (EMI): machinery and electrical drives generate wide-band EMI, potentially disrupting wireless communication
• Physical obstacles: metal structures, pipes, and other physical barriers can obstruct wireless signals, causing reflection and multipath scattering
• Moisture and dust ingress: protecting devices against moisture and dust is essential for long-term reliability
• Hazardous area operation: in hazardous areas with explosive gases or dust, devices must be intrinsically safe – i.e., they must not ignite the surrounding environment

Main low power wireless options

Bluetooth 5, initially a consumer technology, now supports industrial applications with key upgrades. Its long-range mode boosts communication up to 240 metres, suitable for short- to medium-range industrial use. The technology also features mesh networking for extensive area coverage through relayed messages and maintains low power consumption. With data rates up to 2Mbps, it meets the needs of many industrial sensors. A broad ecosystem of compatible devices and tools further aids in reducing market entry time and simplifying implementation.

Wi-Fi is favoured for industrial applications due to its high data rates, with speeds reaching several hundred Mbps in standards like Wi-Fi 5 and Wi-Fi 6, making it ideal for tasks like video surveillance and real-time monitoring. However, its higher power consumption could be a limitation for battery-dependent devices. Additionally, Wi-Fi performance can be compromised by EMI and physical barriers typical in industrial settings. Deployments often counter these challenges with multiple access points and repeaters. Wi-Fi 6 enhances efficiency and lowers power use in dense environments with features like OFDMA ((Orthogonal Frequency-Division Multiple Access) and TWT (Target Wake Time).

Wireless HART and SmartMesh IP are secure, robust protocols optimised for industrial use, offering low data-rate, time-synchronised, channel-hopping communication with end-to-end encryption. They excel in environments with significant EMI and physical obstacles, employing proprietary mesh networking that allows devices to relay data, ensuring 99.999% reliability in data transmission even if some nodes are compromised.

WirelessHART enhances process automation by integrating wireless technology with existing HART devices and tools. SmartMesh IP, leveraging low-power 802.15.4e TSCH and 6LoWPAN technology, is designed for widespread IP-based applications with flexible network configurations to balance power and performance across various uses.

LoRa (Long Range) technology supports long-range, low-power communication, ideal for applications needing wide-area coverage with minimal energy use. Operating in sub-GHz frequency bands like 868MHz in Europe and 915MHz in North America, LoRa offers strong obstacle penetration and reliable communication, reaching up to 15 kilometres in rural areas and several kilometres in urban settings. With data rates between 0.3 and 50kbps, it suits applications like environmental monitoring, asset tracking, and smart metering that require periodic data transmission. LoRa networks can adopt a simple star topology with direct end device to gateway communication or a complex LoRaWAN setup for enhanced bidirectional communication and network management.

Cellular IoT technologies like (Narrowband IoT) and LTE-M (LTE for Machines) deliver wide-area coverage and are effective for long-distance reliable communication. Utilising existing cellular networks, they extend coverage even to remote areas where other wireless methods may not reach. NB-IoT, which is optimised for low data rates and sporadic transmissions, suits applications like smart metering and environmental monitoring. Meanwhile, LTE-M supports higher data rates and lower latency, making it ideal for applications needing frequent updates or real-time communication, such as asset tracking and industrial equipment remote control.

Comparison table

Key considerations for selection

When choosing a wireless technology for industrial use, consider several key factors:

1. Range requirements: identify necessary communication distances. Use LoRa and cellular IoT for long-range, and Bluetooth or Wi-Fi for short-range needs
2. Data rate needs: determine required data transmission rates. Wi-Fi suits high data rate needs; LoRa or WirelessHART are better for low data rates
3. Power consumption: assess power requirements and battery life, especially for battery-operated devices
4. Reliability: ensure the technology is effective in noisy environments with potential EMI.
5. Security features: implement strong security to prevent unauthorised access and data breaches
6. Scalability and network topology: evaluate the network's capacity to scale and choose between star or mesh topology based on application needs
7. Ease of implementation and time to market: select technologies that offer simple implementation and rapid deployment to accelerate time to market

Performance trade-offs

Choosing the right wireless technology involves balancing range, data rate, and power consumption. For example:

• Mesh networks: offer better reliability and coverage but can increase latency and complexity.
• Star networks: provide lower latency but may require higher power and are less reliable in environments with many obstacles

Real-world applications

At ByteSnap, we've seen a clear trend towards non-invasive solutions. For instance, our team has developed diagnostic and maintenance devices that are externally mounted on pipes, avoiding system interruption.

Many of these designs are battery-powered, significantly reducing installation costs by eliminating complex wiring requirements.

A key challenge in creating low-power industrial designs is where they need to operate in hazardous areas with explosive gases or dust. The designs need to either be intrinsically safe or housed in an explosion proof case. Both options require complex engineering, but intrinsic safety is typically the better route if it can be achieved as it is generally a lower cost route.

Having worked on industrial sites since the early 1990s, I've witnessed a remarkable evolution in intrinsically safe devices. Thirty years ago, these were limited to simple sensors like temperature monitors. Today, at ByteSnap, we're developing sophisticated DSP systems that operate as intrinsically safe devices, often without encapsulation.

This progress stems from advances in silicon technology and our innovative engineering approaches. We've leveraged these improvements to drastically reduce power requirements, enabling us to design intrinsically safe systems with compact footprints.

Our experience in this field allows us to push the boundaries of what's possible in harsh industrial environments, combining low-power operation with advanced functionality and rigorous safety standards.

ByteSnap Design products are being used in diverse harsh environments as far afield as Alaska to Saudi Arabia, and our technology extends to consumer products running to millions of units.

Best practice tips

Make a thorough assessment of requirements: evaluate the specific needs of your application, including range, data rate, and power consumption.

Consider full lifecycle costs: take into account installation, maintenance, and operational costs over the device's lifecycle.

Conduct EMC/EMI testing: perform extensive testing to guarantee your devices can withstand electromagnetic interference.

Design for harsh environments: use robust enclosures and materials to protect devices from moisture, dust, and extreme temperatures.

Implement robust security measures: use encryption and secure provisioning methods to protect against unauthorised access and data tampering.

Be realistic: implementing an industrial radio system successfully requires compromise. Decide what the most important metrics are, and work from there. 

Conclusion

Selecting the right low power wireless technology for harsh industrial environments requires careful consideration of various factors, including range, data rate, power consumption, and reliability.

By understanding the strengths and limitations of each technology and following best practices, robust and reliable wireless solutions can be developed to enhance operational efficiency and safety. 

Table Sources: https://www.analog.com/en/resources/technical-articles/verifying-smartmesh-ip-data-reliability-iot.html ; https://people.eecs.berkeley.edu/~pister/290Q/Papers/HART/Petersen%20WirelessHART.PDF ; https://www.farnell.com/datasheets/2007100.pdf ; https://www.beaconzone.co.uk/blog/bluetooth-4-vs-bluetooth-5-range/ ; https://www.anritsu.com/en-us/test-measurement/solutions/bluetooth5-02/index ;  https://eyenetworks.no/en/required-good-wifi-signal-strength/ ; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7146203/; https://www.soracom.co.uk/iot-glossary/lte-m/ ; https://www.mdpi.com/2224-2708/13/1/16 ; https://en.wikipedia.org/wiki/LoRa ; https://synzen.com.tw/blog/item/what-is-nb-iot-technology