How to integrate new with legacy wireless systems: 4 considerations

Old to new wireless network integration: Blending the traditional with the new in an increasingly wireless world requires careful attention to capabilities of old wireless technologies and new wireless technologies, such as 4G LTE, upgraded Wi-Fi, and low-energy Bluetooth. While wireless upgrades add capabilities, a well monitoring site application shows that no wireless technology is yet the best, or the most cost effective, for every purpose.

06/01/2014


Figure 1: Sensors report to a human machine interface (HMI). Courtesy: B&B ElectronicsNew wireless technologies, such as 4G LTE, upgraded Wi-Fi, and low energy Bluetooth, will add new device category layers and cloud-based analytics that will coexist with and add value to traditional machine to machine (M2M) monitoring systems for the foreseeable future. New wireless technologies won't eliminate existing M2M data networks and connected devices, as a well monitoring case study shows. Included among new wireless networking options are:

  • 4G LTE. As network engineers build out the 4G LTE networks, providing excellent bandwidth and low latency, 4G LTE presents a high-bandwidth alternative to cabled connections.
  • Upgraded Wi-Fi. Improvements in Wi-Fi are making remote devices like sensors smaller and smarter, and it is becoming easier and easier to position wireless intelligence out beyond the network edge.
  • Low energy Bluetooth (Bluetooth LE, marketed as Bluetooth Smart). Bluetooth LE will let devices operate for months or years on one battery, while simultaneously giving technicians the ability to communicate with those devices using handheld equipment like tablets and smartphones.

These new wireless technologies will work in tandem with the traditional technologies, providing them with dramatic new capabilities and increasing their value.

To do this, network engineers will need to accommodate traditional M2M technologies, some of which are decades old. They will have to be prepared to aggregate, convert, and wirelessly transmit multiple data networking protocols, from Modbus to TCP/IP. While adding millions of smaller, smarter, more capable nodes to networks, wireless technologies also will have to help keep the existing equipment connected and communicating. 

Remote water well monitoring system

I've established a water well monitoring test site in the Arizona desert. It's a tank monitoring system for the Pinal County, Ariz., well owners' co-op, whose purpose is to predict system failures by measuring and aggregating pump current. By building intelligence, or analytics, into the system, I have given it the ability to make decisions based on changes detected over time. Currently, the system can SMS [short message service-send a text message to] a technician to schedule preemptive maintenance before a catastrophic failure.

I've added new networking technologies whenever it made sense to do so. But I've often kept existing equipment in place as long as it continued to do the job efficiently, and at a reasonable cost. To draw an analogy, think about the tire pressure gauges that we all keep in our toolboxes. The newer, digital versions are easier to read. But they cost more, they require batteries, and they tend to be more fragile. Are they always the better choice?

Below examine four considerations that went into present and future upgrades for this wireless monitoring application, integrating new wireless technologies with existing, legacy wireless capabilities. 

1. Centrally gather and analyze sensor data.

In an earlier incarnation of my Pinal County site, I used I/O [input/output] radios to transmit data from pressure sensors, current sensors, and level sensors to a radio modem. The radio modem then connected to an on-site human machine interface (HMI). It was a convenient way to gather all of the data in one location, as Figure 1 shows. But I had to be physically present at the site if I wanted to review it. 

2. Add wireless Internet access via the cellular network.

Figure 2: Sensor system integrates cellular backhaul capabilities. Courtesy: B&B ElectronicsLater, I added a 3G cellular router to the mix. It provided Internet backhaul via the cellular telephone network, making it unnecessary to visit the site in person. I could now monitor the site anywhere I could establish an Internet connection. The router had built-in firewalls and powerful security protocols, and when combined with virtual private networking (VPN), I used the cellular system as securely as if it were proprietary infrastructure. (See Figure 2.) Note, however, that I didn't have to discard my Modbus sensors, my I/O radios, or my radio modem. By adding cellular networking to the site, I merely expanded its capabilities. I wasn't starting over from the ground up, and I didn't need to replace all of my existing equipment.

At this point, you could say that I was simply using the cellular router as a protocol converter with cellular backhaul. But as I've added additional devices and additional protocols to the system, I'm taking better advantage of the router's ability to function as a data aggregator with multiple backhaul options. Now that I've attached an IP security camera to the router's Ethernet port, for example, I'm not just able to remotely monitor the data from my sensors, I can actually view the site in real time. 

3. Exploit data aggregation and backhaul capabilities.

There are numerous upgrades that I could add to the site right now, if I felt the need. If I wanted full motion video, I could upgrade to a 4G LTE router and take advantage of 4G's bandwidth. I could streamline the installation by replacing my older sensors and I/O radios with Wi-Fi sensors that reported directly to the cellular router, as Figure 3 shows. 

4. Deploy future wireless technologies and sensing applications.

Figure 3: 4G LTE router has Wi-Fi. Courtesy: B&B ElectronicsI'll make changes as the need arises. At some point in the future, I'm sure that I'll want to add new networking technology to the site and additional sensing capabilities. Corrosion sensors, which measure the remaining thickness of a pipe or vessel, would tell me how my water tanks are holding up, and whether I should be thinking about replacing one. If a new industry appeared in the neighborhood I might need to keep a close eye on the quality of the water in the well and watch for contaminants. Entirely new sensing capabilities will come along as well, and it's likely that I will find some of them useful.

The site will continue to be an integrated mix of wireless monitoring and sensing technologies. So, like most networked systems, my well monitoring site will continue to evolve, and it will continue to be a mix of the traditional with the new. No single technology is yet the best-or the most cost effective-for every purpose.

- Bill Conley is the M2M systems development engineering manager at B&B Electronics. Edited by Mark T. Hoske, content manager, CFE Media, Control Engineering, mhoske(at)cfemedia.com.

Key concepts

  • Rip-and-replace strategy isn't needed when integrating new with legacy wireless systems.
  • Heed 4 considerations and 3 new wireless technologies when upgrading wireless technologies and related capabilities and applications.
  • Application notes: See the lessons learned from wireless upgrades, past and future, at a well monitoring site.

Consider this

Wireless infrastructure upgrades can enable functionalities and applications that add efficiency, security, and reliability, without ripping out existing wireless nodes.

www.controleng.com/wireless

www.controleng.com/enewsletters has the System Integration enewsletter, which includes wireless networking topics.

www.controleng.com/webcasts has Control Engineering wireless and other networking webcasts, some for PHDs.

See additional wireless coverage below, including wireless tips and tricks, wireless infrastructure, and wireless Murphy's Laws. 

More about the author

Bill Conley is the M2M systems development engineering manager at B&B Electronics. He has more than 30 years of experience in the wireless field as an embedded design engineer, specializing in the digital, microcontroller, and microprocessor arenas.

Conley was the first Aerocomm (Laird Technologies) certified wireless design engineer, and the first RF/wireless certified design engineer for Maxstream/Digi.

Conley has designed SCADA and telemetry solutions for remote monitoring and control for 20 years, earning "Most Innovative Product" for one of the first wireless mobile MDTs (Land Mobile EXPO) and "Best of Wireless Telemetry" (2002 Sensors Expo).

Conley is a frequent author and speaker, and holds several patents in the industrial wireless field. He is a TIA delegate to oneM2M, a standards body focused on global interoperability of M2M.



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