Level transmitter calibration
A level transmitter is an instrument that converts the output of a Level sensor into either an analogue signal or a digital signal that can be transmitted to a remote location.
Generally, output of a level transmitter is analogue signal. Pneumatic level transmitter output is 3 -15 psig or 6-30 psig. Electronic level transmitter output is 4-20 mA. Pneumatic or electronic transmitter selection is made to the compatibility of indication, alarm and controlling system.
The signal from a transmitter may be transmitted to switches, controllers, or PLC. The transmitter output may be used for several different functions like controlling, alarm, shutdown, etc. The difference between a controller and a transmitter can be just a matter of semantics.
There are level transmitters with the dual head with a controller. In such instruments, the transmitter portion would be transmitting the level measurement to a remote location. The controller portion would be controlling the liquid level in the vessel through a final control element.