Wireless communication in industry is, of course, nothing new. Most applications of industrial wireless to date have involved either Wi-Fi or NFC (near field communication). But there’s growing interest in the use of Bluetooth for wireless communication, with around 7% of industrial companies currently reporting use of it, according to Mark Trautman, strategic account manager at HMS, during a presentation at the 2025 ODVA annual meeting.
One of the reasons Bluetooth is gaining interest versus NFC is that, although they both use wireless technology to exchange data, NFC devices can connect to just one other device at time, while Bluetooth can support up to seven device connections at a time. Also, NFC uses electromagnetic radio fields to connect devices — which can be an issue in industrial environments that often have EMI (electromagnetic interference) issues — while Bluetooth uses direct radio transmissions.
The purpose of this presentation at the ODVA meeting was for ODVA members (industrial automation device suppliers) to learn about how Bluetooth can be used in industry and the steps ODVA members should be considering to enable industrial Bluetooth applications with their devices. But there were great insights for manufacturing end users as well.
Trautman said the initial applications for Bluetooth in industry relate to hard-to-reach sensors where direct cable connections are difficult or impossible. He cited Bluetooth’s mesh network topology as a major reason for Bluetooth’s applicability here. The technology also supports star topology applications.
Plus, because most everyone uses Bluetooth every day, it’s a familiar technology that has a lot of potential for connected worker applications.
How Bluetooth supports industrial communications
Zach Farmer, business manager at HMS, noted that version 5 of Bluetooth Low Energy (BLE) supports data transmission of up to 2 Mbps and that version 6, which was released in September 2024, supports up to 3 Mbps at 2 MHz. He added that, while Bluetooth Classic is still supported by the Bluetooth organization, most of the organization’s focus is now on developing BLE. As indicated by its name, BLE has significantly lower power consumption compared to classic Bluetooth.
Farmer pointed out that, while Bluetooth packets are not as large as those that can be transmitted via Wi-Fi Ethernet, they do have enough capacity to deliver the majority of small device CIP (Common industrial Protocol) communications used by EtherNet/IP and DeviceNet.
Addressing Bluetooth’s reliability for industrial use, Farmer referenced the technology’s frequency hopping and shifting.
“When a Bluetooth device is trying to bond with another device, they pass information with each other. The Bluetooth device also scans the area to know what the [network] noise level is and will avoid channels that are too noisy. If, for some reason, the devices might not initially be able to interact with each other, the Bluetooth device will hop around to find open channels within the spectrum so that communications can be established,” he explained. “Since the release of version 6, we now have three broadcast channels, originally for the purpose of pairing and passing information with BLE. The other 37 channels can be used as secondary broadcasting channels if needed.”
Bluetooth security
Security is, of course, a high-level concern with any wireless technology, and Bluetooth is no exception.
Farmer noted that BLE addresses this with the ability to send a randomized MAC address during the connection process. “An identified resolution key is used to know what the MAC address is,” he explained. “The communication channels are also encrypted to prevent sniffing. So, you're not going to be able to access it unless you’re [an established] part of the channel.”
He also pointed out that a Bluetooth device needs to be in broadcast mode to be added to a network.
“Since they are not always broadcasting to look for new devices to be added, you need to specifically request that to be done,” he said. “This means the devices connecting know who they are and that there’s not a third-party device trying to come in and copy the connection.”
Bluetooth industrial use cases
Todd Wiese, systems architect and principal engineer at Rockwell Automation, explained that “any sensor capable of using a broadcast access point can scan for local Bluetooth devices and report the values they're sensing [to that device].”
Devices can also use PAWR (periodic advertising with response), which was developed in Bluetooth version 5.4, according to Wiese. “This provides a time slice scheduling of the network so that you can request a group ID of devices and then either send implicit requests for the current values of the data — similar to what’s done with acyclic connection — or encode a request through a command for a class instance attribute, allowing you to return the data as the response for that event. Here, the master device sends out a broadcast related to a group ID that identifies those specific devices and generates sub-events. The sub-events include each one of the devices that are on that group, allowing it to respond within a certain time frame. This can be scheduled all the way down to five or 10 millisecond responses or up to one second, depending on the application.”
Two examples Wiese offered included a battery powered PoE (power over Ethernet) device and using a smartphone to interact with a device.
With the PoE device, Bluetooth can be used to monitor its power use to estimate remaining battery life. In this application, you can “relax the amount of time needed to query the device based on how you want to manage it,” Wiese said. “Of course, there's still going to have to be some level of management [of these communications], just as is done with ControlNet, where you have to schedule things to make sure they will fit within the broadcast periodic interval, but the capability is there to do this.”
For the smartphone example, he explained how Bluetooth can be used to configure a device. “Here, we use the CIP application protocol above the encapsulation layers that we typically use with Ethernet. But we still use TLS to securely transfer the information from the smartphone,” said Wiese.
“So basically, what we're doing is getting rid of the lower layers — the IP layer and below — and using TLS to create the security context from where you're getting the message all the way down to the device you're communicating with,” he explained. “We could connect directly to the device or route the communications from the smartphone through a gateway with a security context established to the endpoints on other devices on the Ethernet network. This approach uses TLS to wrap the information into a core package and deliver that information securely down to the individual devices.”
