Zero Elevation occurs when a transmitter is mounted where?

• A. Above the bottom of the tank
• B. Below the bottom of the tank
• C. At the bottom
• D. Inside the tank

Answer: (A)

Zero elevation is about choosing the reference height for the level transmitter’s sensing point. In hydrostatic level measurement, what matters is the height of liquid above the sensing tap, because that height creates the pressure the transmitter converts into a signal. mounting the transmitter above the bottom keeps the sensing port clear of bottom deposits and allows a stable, repeatable reference point for zero and span. It also avoids placing the sensor in direct contact with the tank floor or inside the tank, which can invite fouling, turbulence, or damage and distort readings. If the sensor were placed at, below, or inside the bottom, readings would be less reliable due to sludge, pressure from the bottom, or immersion effects, shifting the zero and impairing accuracy.