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Reference Manual
IP2048/RM, Rev AA
Section 2: Transmitter Overview
February 2015
3
Section 2 Transmitter Overview
Introduction to the transmitters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 3
Theory of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 3
Components of the transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 4
System architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 4
2.1 Introduction to the transmitters
The Mobrey MSP400RH and Mobrey MSP900GH are 4–20 mA loop-powered transmitters, and
are designed for liquid level measurement applications.
2.2 Theory of operation
The Mobrey MSP400RH and MSP900GH ultrasonic liquid level transmitters are mounted above
a liquid and use ultrasonic pulses to continuously measure the distance to the liquid surface. The
electronics calculate the distance to the liquid level using the time delay between transmitting
and receiving signals (Figure 2-1).
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 signal
and a digital HART
®
signal.
The MSP400RH and MSP900GH can also calculate contents volume or open channel flow, when
programmed with further application information, and then outputs the result as a
4–20 mA signal and a digital HART signal.
Figure 2-1. Typical Application using Mobrey MSP400RH and MSP900GH transmitters
A. Transmitter Bottom Reference B. Distance C. Level
A
B
C