Many tanks, so it seems, are at the edge of existence. They make their home in the scorching desert, the frozen tundra, in the middle of cornfields, or on a steep mountain slope. While these landscapes may be breathtaking, they certainly don’t make sensor deployment easy or cheap.
And even if your tanks are city dwellers, you still don’t want to get unnecessarily spendy on your telemetry. That’s why a pressure transducer is an ideal choice.
Pressure transducers are one of the least expensive technologies in the continuous level measurement world, and they’re ideally suited for use as a water level sensor in a remote tank because they work so well with batteries.
One way to save money on the installation of a tank level sensor on a remote tank is to go totally wireless. That means wireless communications and wireless power supply, or batteries. So choosing a tank level sensor that plays nice on battery power is essential.
There are two reasons a pressure sensor performs well with batteries:
Let’s take a look at each to understand why they’re so critical.
In order to work well with batteries, your level transmitter needs to draw very little current. This is tough for a lot of sensors. Many sensors rely on a transmitted pulse of some kind. Ultrasonic sensors have to excite a sonic transducer. Radar sensors must produce microwaves. Magnetostrictive transmitters send electrical pulses down a wire. The list goes on.
However, a pressure transducer simply routes the current through its Wheatstone Bridge and measures the change in resistance. This inherently requires less power and improves battery life substantially.
The problem of having to transmit a pulse or wave that many continuous level sensors face is longer response times. It takes time for those pulses to come back to the sensor, and even more time to receive enough of them to qualify a level reading.
Time is a battery’s enemy. The more time the sensor has to be powered on, the faster power is drained from the battery.
In contrast, a pressure transmitter doesn’t have to wait for a returning pulse or wave. It takes only a few milliseconds to qualify and transmit a level measurement.
The fact is most of the tank farm owners and engineers we talk to are demanding 3-5 years of battery life. We achieve that by working with our partners who carry impressive batteries and communication equipment, and by carefully managing when the sensor takes a measurement.
The goal is to program your sensors to come on at a certain interval, take a measurement and transmit it, and then turn off. This is the only way to make a battery last much longer than a month or so.
Mating the right sensor with this strategy can give you a battery life of several years – varying only on how often you choose to take a measurement.
Using a pressure sensor, whether it’s a submersible or externally mounted pressure transducer, usually makes the most sense. They’re usually accurate enough and work reliably for many years. Add that with improved battery life and you have a winning combination.
Contact us if you have any questions about pressure transducers, battery-powered sensors, or remote tank level monitoring.
top photo credit: U.S. Department of Agriculture via flickr cc
