Rosemount 3107, Reference Manual

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Reference Manual
00809-0200-4840, Rev BA
Section 2: Transmitter Overview
December 2014
2.2 Theory of operation
The level transmitter is designed to be mounted above a liquid ( Figure 2-1 on page 3 ), and uses
ultrasonic pulses to continuously measure the distance to the liquid surface. The electronics
calculate distance to the liquid level using the time delay between transmitting and receiving
signals.
When programmed with the bottom reference of the application – usually the bottom of a tank
– the transmitter calculates the liquid depth (level), and outputs the result as a 4–20 mA and
HART signal.
The 3108 and the 3107 can calculate contents (volume) or open channel flow when
programmed with further application information, and outputs the result as a 4–20 mA and
HART signal.
2.3 Components of the transmitter
The transmitter has a housing containing advanced electronics to generate ultrasonic pulses,
process the resultant signals, and provide a 4–20mA and HART
®
output.
There is a factory-fitted cable for the signal output and connecting an external power supply.
The 3108 has a factory-fitted Remote Temperature Sensor.
Figure 2-2. Transmitter components
A. Mounting bracket D. UPVC wetted parts
B. Two-core cable E. Remote temperature sensor (3108 only)
C. 1-in. mounting thread
D
C
E
B
A
D