The Big Sensor Theme at WEFTEC – If You’re Not Smart You’re Dumb
The Big Sensor Theme at Weftec – If You’re Not Smart You’re Dumb
Author: Mark Spencer
Make no mistake. Trade shows are back. People are sick of Zoom. They want to talk to real people, and they love booth swag. At WEFTEC 2023 attendance was at 90% of pre-pandemic levels. The 2023 Weftec was not your 2019 Weftec. Our industry has been famously resistant to change but change is inevitable. Here are my thoughts on what grabbed attention at our booth and what I observed in others.
Gone are the days when a good probe was good enough to build a company. In 2010 I bought the AquaMetrix product line largely on the sterling reputation of the differential pH/ORP probe. Don’t get me wrong. The original AquaMetrix is still the goose that lays the golden egg—which is our differential pH/ORP probe. Nevertheless, wandering through the halls, I could not help but conclude that a plain, vanilla sensor is a commodity—even a really good one. We all know that the only thing that separates one commodity from another is price. To stand out in the crowd, so that price is not the determining factor, manufacturers know that they must show off a sensor, and any associated electronics, that are unique.
In prehistoric times—ten years ago—most probes, including ours, were “dumb.” This means that the power and signal processing are all incorporated into the transmitter. This makes sense, especially in the wastewater field, when you want a probe to have the bare minimum amount of electronics in harm’s way. Replace the dumb sensor, keep the smart electronics. If there was a beachhead for direct output sensors it was analog (4-20 mA). Modbus, Profibus, Fieldbus, whatever-bus: They sold decently in Europe but never really caught fire here in the states.
I recall in 2010 seeing the AquaSensors DataStickâ. (AquaSensors was purchased soon after by Thermo-Fisher). It was a modular probe that allowed the user to replace the sensor front end (pH, ORP, conductivity, turbidity, D.O.) and the communication end (Modbus, Ethernet, or USB). It was a trailblazer that was way ahead of it time, but its high price, necessitated by the modular construction, limited its adoption. To be clear, there are still benefits for a separate transmitter, but customers want the option of going direct.
Fast forward ten years and electronic circuits have become cheaper, smaller, and more robust. Today a smart sensor can be had for somewhere between $200 and $500 more than its dumb cousin—not insignificant but much less expensive than a standalone transmitter. According to a Markets and Markets report (2021) the growth of sensors for industrial sensors is growing at an annual rate of 9.1% and will reach $32 billion by 2026. The driving force behind the growth is the digitization of sensor data that we see labelled as “Industry 4.0” or “IIoT.”
This rise of the digital output sensor was on full display at nearly all the WEFTEC booths hawking sensors. At our booth the number one question was “Can I connect it to my PLC?” Our smart conductivity probes (AS-TX) and pH/ORP probes (pH-TX) were the items that attendees wanted to touch. Controllers, like the web-based AM-2300 or bread-and-butter AM-2252 were “pretty” but the new direct output sensors were the draw.
Going direct once meant one thing— 4-20 mA output. I’m not sure that the 4-20 mA (“analog”) format will ever die. Nor should it. It was sheer genius—almost a century ago—to engineer two wires that can power a sensor and carry signal information. Because the signal is current it can go hundreds of meters without losing strength (as a voltage would). Long live Analog! But there are two downsides:
- You get only one parameter (e.g., pH) and not a second (e.g., temperature), unless you want the added expense and complexity of HART.
- Analog communication is not inherently electrically isolated. Put another probe or an electric device (e.g., a mixer) and you can get nasty interference which necessitates adding an isolator.
The AquaMetrix product line has always included 4-20 mA output versions of our flagship differential probe and our other sensors (dissolved oxygen, turbidity, and chlorine) are now only offered only as 4-20 mA output probes. But digital is here. My assessment is that Modbus is the prevailing digital standard. It’s old but it’s open (no licensing fee!) and not overly complicated. If you live in the Rockwell PLC world, then Ethernet/IP is the standard.
We at AquaMetrix decided to overhaul the electronics of our pH, ORP and conductivity sensors by designing one common circuit board platform that can be populated to provide “raw” output (to be used with a separate transmitter like our AM-2250), 4-20 mA output or Modbus output. One board—three options.
The only digital trend that I did not observe is wireless communication. It costs about $100 per foot to lay cable and the cable prevents the probe from being removed from the process and calibrated in the lab. Wireless is inevitable but the hurdle to clear for its adoption is high. Concrete and rebar have a tendency to make communication spotty. It doesn’t help when there is a profusion of wireless digital protocols: WiFi, Wireless HART, Bluetooth, Zigbee, ISA 100, NBIoT, 5G, Z-Wave and LoRa all compete for attention. Each one meets a specific need. For applications that don’t require high data transmission (> 1 Hz) communication but long range and robustness the two low-power, two LoPWAN) protocols‚ NBIoT and LoRa, are the leading contenders. We at AquaMetrix have place our bets on LoRa and I believe that it will be the “VHS” to the “Betamax” NBIoT. I see the LoRaWAN label everywhere. (You can tell I’m a Boomer.) We put our money where our mouth is and put LoRa on our new digital FOG sensor. If it works out as we hope it will become the basis of all our next generation sensors. Stay tuned!
Were you at Weftec and came back home with a takeaway? I’d love to hear. Email me at mspencer@wateranalytics.net.
Want to know more about how we are transitioning toward a digital future email me or Brian Gannon at bgannon@wateranalytics.net.
Team