If you need a remote liquid level sensing solution for your tank farm, you basically have two options. Option one is wired Ethernet sensors. These connect to a LAN or the Internet via standard equipment. Option two is self-contained cellular sensors. These sensors have a built in cellular modem that allows them to connect directly to the Internet via a cellular network.
As you may have already guessed, each solution has their own set of advantages and disadvantages. While the self-contained cellular sensors are easy to install and implement, they have more expensive long-term data management costs. Each tank will have a sensor with its very own gateway to the Internet. On the other hand, the wired Ethernet sensors can be difficult to install, but are less expensive in the long run because multiple Internet connections are not required.
So how do you get the best of both worlds? Here at APG, we recently helped one of our customers do just that with their tank farms.
Our customer has over a hundred small tank farms scattered throughout the United States. Each farm typically has 3-5 chemical tanks. They had been searching for a remote sensing solution that was both easy to implement, and light on the data management costs. In other words, they wanted to reduce costs in both the short and long term. We were able to help them achieve this by utilizing our remote monitoring system, which consists of wired Ethernet sensors.
We just covered how wired Ethernet sensors are difficult (read expensive) to install. However, we’ve made it easy for tank farms, because we only use one Ethernet sensor. The others talk to the one Ethernet sensor using a communications protocol known as Modbus.
Let’s take a moment to define a few terms: Modbus is a type of communication standard that requires very little wiring. This is done through a simple system of server and client sensors connected on a daisy chain. The server sensor collects data from the client sensors by querying each of them. Each client reports its level measurement to the server. A daisy chain is a simple and inexpensive wiring structure in which multiple sensors are connected in a chain-like sequence (to give you a better idea, a daisy chain wiring scheme is also used for lights on a Christmas tree, or even for the electrical outlets in your home).
Our remote monitoring system, as previously stated, uses one Ethernet sensor. This same sensor happens to be the Modbus server on our sensor network. So it packages all of the data gathered from itself and the client sensors, and sends it to us over the Internet, using whichever Internet connection is most appropriate.
Now that we cleared that up, let’s get back to the customer with the tank farms.
At each of our customers’ locations, they installed one of our server sensors (the LOE) and between 2 and 4 of our client sensors (the MNU), depending on the number of tanks at a particular location. Then, by connecting the server sensor to an Internet connection via Ethernet, the customer is now able to remotely access tank level data for all of their locations. They simply log onto our online data portal from any Internet connected device, anywhere in the world.
So using our remote sensing system (which uses Modbus), our customer was able to minimize their data management expenses by keeping the number of internet connections to only one per location. And due to the simple but effective structure of the daisy chain, our customer was able to diminish installation challenges.
