Wireless technology has made a huge impact in our world. Information can now be gathered and transmitted more quickly and efficiently than ever before. In the process instrumentation industry, this means being able to monitor tank levels, pressure, temperature, and other variables in areas that we haven’t been able to before. We are able to save considerably on upfront installation costs by transmitting wirelessly rather than running long cable and conduit runs.
But while wireless technology has its benefits, there are some often overlooked costs involved. These include proving remote power, dealing with signal interference, and the added cost of troubleshooting. So if not implemented properly, you could end up eating all of those dollars you saved and a lot more.
Running power cables out to the sensors would defeat the purpose of going wireless. So this leaves you with batteries and solar panels as your only options for powering your sensors and communication equipment.
Along with wireless, battery technology has made significant improvements over the years. But we still need to be mindful of using that limited power efficiently. Careful consideration must be taken into how often data should be transmitted as well as what sensor to use.
For example, some batteries claim to last 5 years or more. But there are some caveats; make sure you read the small print. From what we have seen, battery life for remote monitoring systems is usually based on one transmission per day. So if you have a more critical application that needs to be monitored every few hours or every few minutes your battery life will be drastically reduced.
There may also be limitations on what sensors you can use. Not only should you check what the power consumption is for the sensor but also its warm-up time. Some sensors can be powered up take a measurement and transmit in a few fractions of a second. On the other hand, some sensors require many seconds to get a stable/accurate reading. This can have a major effect on the life of your batteries.
Essentially, you need to build a power budget. Determine how much your battery is offering and calculate how long it will last based on the frequency and duration of each measurement event.
One way to extend the life of your batteries is to add solar panels. There are many issues to consider with these as well, such as how large the panel needs to be as well as the sun exposure for a particular process location. We won’t get into further details on solar panels for this discussion but be aware that buying solar panels does require some research and planning as well as a significant added cost to an installation.
None of this is a deal breaker if you’ve done your homework. Make sure you seek out sensors that work well with batteries. Limiting the frequency of your measurements always helps.
Many things can create issues for a wireless signal that wouldn’t be a problem for wired signals. Obvious examples include trees, hills, and other geographical features.
Much can be done in the planning stage of an installation to avoid problems resulting from geography. However, in our experience, there are always unforeseen obstacles that show up at some point. For example, some sensors on a wireless network might intermittently go offline due to bad weather or even a large vehicle that may park too close to a sensor. This can cause a lot of grief and headache for operators that are remotely monitoring the site. Unexplainable, intermittent issues are very difficult to troubleshoot.
To avoid instances like this, it may make more sense to deploy a mesh network rather than a point-to-point system. So when the unexpected does happen, other nodes on the chain will still be able to find a pathway back to the gateway device. This will greatly reduce the risk of sensors going offline due to unforeseen obstacles.
Signal interference is going to happen, but you can mitigate this problem by using the right technology for your installation.
When sensors go offline you often have no choice but to send a technician out to troubleshoot. In some cases this can involve booking a flight, hotel, and other travel expenses. This can be especially frustrating when the signal problems are intermittent. Sometimes it can take several trips before a problem is finally diagnosed and fixed, costing thousands of dollars.
You might also find that even during installation, you’re spending a lot more time troubleshooting – especially if you’re new to wireless. This added time and frustration is an expense for which you should be prepared.
Wireless communications can greatly reduce cost, but there is a built-in learning curve.
Wireless technology has many benefits that can change the game for your business. It is often the better choice for remote monitoring applications. However, we want to make you aware of some challenges with using wireless technology and why, in some cases, going wired may be better.
While running cables and wires can be expensive upfront, in some instances, they end up paying for themselves down the road by reducing troubleshooting time and costs.
If you have questions about whether wired or wireless sensors are better for you, contact us to talk it through. We’ll recommend the best option and connect you with the right people to get you started down the correct path.
top image credit: Tax Credits via flickr cc
