Liquid level transmitter is a term used for a liquid level sensor that transmits an electrical signal that is converted into a liquid level. Level transmitters normally have ranges that they operate within to maintain “normal liquid level” or “NLL”. The control system can be set up with a high liquid level (HLL) or a low liquid level (LLL) alarm that can send a signal to pumps and or control valves so they can take necessary action to maintain normal liquid levels. Level Indicator or Tank Level Gauge are two terms used for a level indicator. They are used for continuous indication of liquid level in storage tanks and vessels where visual indication at the tank is required.