Emerson 3107 ユーザーズマニュアル

3

December 2014

The Rosemount 3107 and 3108 are sealed 4–20 mA loop-powered liquid level 

transmitters, specifically designed for use in waste water and effluent treatment plant 
on aqueous applications.

These rugged UPVC transmitters are certified Intrinsically Safe for use in Zone 0 areas, 

and factory fitted with up to 165 ft. (50 m) of two-core cable for simple low cost 
installation in sumps, wet-wells and over open channel flow structures.

The transmitter may be mounted in a hazardous area if powered from a protected 

power supply. They can be connected directly to a plant control system, or used with a 
Rosemount 3490 Series Control Unit for programmable control functionality.

Theory of operation

Each transmitter is designed to be mounted above a liquid, and uses ultrasonic pulses 

to continuously measure the distance to the liquid surface. The 
microprocessor-controlled electronics calculates distance to the liquid level from the 
time delay between the transmitting and receiving of signals.

When programmed with the bottom reference of the application – usually the bottom 

of a tank – the transmitter will calculate the liquid depth (level), and output the level 
(

) as a 4–20 mA signal and a digital HART® signal.

The 3107 and the 3108 can also calculate contents (volume) or open channel flow, and 

then output the result as a 4–20 mA signal and a digital HART signal.

Programming is achieved by remote communication using HART.

A. Rosemount 3108 Flow Transmitter

E. Pump

B. Rosemount 3490 Series Control Unit

F. Transmitter Bottom Reference

C. 4–20 mA signal output

G. 4–20 mA and HART signal input

D. Relay