Level measurement, together with pressure, temperature and flow, are the most important and common variables in refineries, textile, food, pharmaceutical and chemical plants. At the level of plant automation, HMI (Human Machine Interface) is also required.
In this project, I included both measurement and HMI in an easy way. This project consists in monitoring the level of water in two tanks. Information about the level of the liquid in the tank will be shown in a screen where you will be able to see the numeric values and the graphic values.
There are many ways to sense level. You could use pressure sensors, ultrasonic or discrete (switches) sensors. I use potentiometers attached to a floating mechanism to bring “analog data” information to the Arduino board.
For the HMI, I found an application for Arduino in the web, develop by Ulrich Albert Maassen. The web address to download this application is: www.SerialComInstruments.com
In the next figure, I show the screen for my project. Blue boxes represent the tanks; in the upper side are the numeric values expressed in % (0-100). At the top of the screen, you can see the trending of both levels of the tanks.
SerialComInstruments allows you to create environments to see trends, X-Y graphics, numeric displays, vertical meters and digital displays. By selecting the field “instruments,” you can select a diversity of resources for your project.
Then, you can select the serial “Interface” where you specify: Com Port, Baud Rate,and you can also change the Data Protocol.
If you select “Show”, you will be able to Connect and Disconnect the interface, and you can go to the Edit Mode. In this mode, you can build your display.
Next, some pictures of the project: