Gauge and differential pressure transmitters are reliable, cost-effective instruments used to measure the hydrostatic level of liquids—such as water or fuel—in both vented and sealed tanks. These tank level pressure transmitters are designed to be mounted at the bottom of the tank. Typically, they are threaded into the tank’s outlet line, a side bung, or a flange for installation.  

As transmitters deliver a linear output signal (e.g., a 4 to 20mA signal ranging from zero pressure to full-scale pressure), liquid level can be monitored based on the liquid’s density and the tank’s height. The actual shape of the tank is only necessary when the user needs to calculate the volume of liquid based on the measured level. 

VENTED TANK Gauge versus Differential

In this scenario, the sole distinction between a gauge pressure transmitter and a differential pressure transmitter lies in their venting configurations: the differential pressure transmitter features a P2 port vented to the atmosphere, whereas the gauge pressure transmitter typically incorporates a vent tube within its cable to accommodate fluctuations in barometric pressure.  

The vent tube of the gauge pressure transmitter must be protected from humidity, particularly when there are significant temperature differences between the liquid and the surrounding atmosphere. This protection is commonly achieved by venting the sensor inside a control box equipped with desiccant or by installing a desiccant filter at the end of the vent tube. 

Reliable and easy-to-use level sensors, designed with you in mind

Our extensive range of level transmitters, detectors, switches, and accessories for measuring liquids and solids will help you optimize processes and enhance safety at your plant—whether for the most demanding and extreme applications involving viscous, corrosive, or aggressive media, or for simpler operational scenarios.  

Experience ease of use, reliability, and accuracy with Emerson's Rosemount level measurement sensors and technologies. 

Guided Wave Radar Level Transmitters employ microwave technology to perform continuous level and interface level measurements of liquids, solids, and slurries. Emerson’s market-leading product portfolio delivers accurate, reliable, safe, and cost-effective level measurement solutions, even in the most demanding process conditions. Equipped with powerful onboard diagnostics, these transmitters provide valuable insights into device health and signal quality, ensuring you have confidence that your process remains under control. 

TE M10X1 mV Miniature Pressure Transducer

Rosemount™ 3300 Level Transmitter - Guided Wave Radar

For level and interface measurement tasks, the Rosemount 3300 Level Transmitter offers a reliable and cost-effective solution for liquid applications. The Rosemount 3300 features a design with no moving components, requires no calibration, and remains virtually unaffected by varying process conditions. Thanks to its top-down level and interface measurement capabilities, you maintain complete control over your level monitoring processes.