One of the first questions we get asked about our remote tank level monitoring system, Tank Cloud, is whether or not it’s wireless. The answer is no, but we integrate very well with wireless. There are really two ways to cut the cable and go wireless with remote sensors:
Each has its own set of pros and cons. So which should you choose? This article will discuss when you should use each.
The biggest difference between radio and Wi-Fi is range. Radios are capable of a lot of frequencies that give them a variable range. You can get radios to communicate over many miles when they have good line of sight.
Wi-Fi, however, is limited to 2.4 or 5 GHz. These frequencies can cover a few miles when their signals are directed by upgraded antenna. However, as this is more expensive, Wi-Fi is usually used in a much shorter range of a few hundred feet.
As soon as you start discussing frequencies, you have to cover interference as well. A lot of devices rely on the 2.4 and 5 GHz frequencies, which means these devices can be vulnerable to interference from each other.
By contrast, radios use a variety of frequencies (including 2.4 and 5 GHz) and can avoid interference from surrounding devices.
Signal interference can be a serious problem because it changes the signal coming from your sensors. It can make your monitoring system completely unreliable. Make sure you’re aware of other wireless signals in the area before you decide what frequency you want to use.
Remote monitoring promises to lower your cost of managing your remote tanks dramatically. However, it can quickly get out of hand if you don’t plan the project carefully.
Thankfully, there is not much of a cost difference between using Wi-Fi and radio equipment.
Both Wi-Fi and radio can be quite power hungry when transmitting long distances. It simply requires a lot of juice to produce a signal powerful enough to travel very far. However, their different protocols play an important role here.
Wi-Fi protocol is designed to stay on all the time – like the broadband wireless router in your home. That presents a problem when you need to use batteries.
Radio, on the other hand, is happy to be turned off and back on again – causing only a small delay for the radios to reconnect.
Of course, you can power your Wi-Fi bridge off and on; it just takes them a little longer to reconnect. And those precious extra seconds force the whole system to remain on while the network re-establishes itself. That costs power.
When using batteries, your sensors and communications equipment must be able to turn on and off quickly to conserve battery. Otherwise, you’ll be changing your battery more often, which takes time and costs money.
The goal of a battery-powered system is once again to reduce wiring and save money. Batteries are expensive, so they need to last as long as possible to give you the ROI you’re looking for.
Finally, it’s important to consider the pre-existing communications infrastructure where you’ll be installing your remote sensors. Are you trying to put sensors in the middle of nowhere? Or are they going a few hundred yards away from your building?
In the first scenario (middle of nowhere), there is no pre-existing infrastructure to worry about. You need to find a reliable link to your network – usually via the Internet – but you can make a decision without worrying about compatibility.
However, in the second scenario, you’ll likely have a network in your building. You probably don’t want to connect to the Internet, but to your existing monitoring and control network. If you’re using Wi-Fi already, why not just extend it to your sensors?
It’s actually pretty easy to decide between Wi-Fi and radio equipment. In some cases, it won’t really make much of a difference and you can go on cost and availability. In other cases, when distances are long or interference is a concern, the choice will be clear.
If you have questions about sensor networking in remote locations, give us a call, or drop our Measurement Experts an email. We work with a few companies that provide this equipment and integrate very well with our sensors. We’re happy to put you in touch with the right people to set your project up for success.
top photo credit: {Charlotte.Morrall} via photopin cc
