An automatic tank gauge (ATG) is an electronic device, whose basic function is to monitor the fuel level in the tank over a period of time to see if the tank is leaking. It can also tell the facility operator what is going on inside the tank (example: fuel level, volume and temperature, water
level and volume, high and low fuel level warnings).
Other features can be added to the ATG so that it can perform useful functions such as monitoring the interstitial spaces in tanks and piping, monitoring pressurized piping, or communicating remotely.