Service Overview; Analyzing The Measurement Signal - Emerson Rosemount 5402 Reference Manual

Service and Troubleshooting
October 2018
7.3

Service overview

The functions mentioned in this section are available in the RRM configuration program.
7.3.1

Analyzing the measurement signal

RRM, and other tools using enhanced EDDL, has powerful functions for advanced troubleshooting. By
using the Echo Curve plot function, an instant view of the tank signal is displayed. Measurement
problems can be resolved by studying the position and amplitude of the different pulses.
Figure 7-1. The Echo Curve Presents all Visible Echoes
In a typical measurement situation, the following pulses appear in the diagram:
Reference. This pulse is caused by the transition between transmitter head and antenna and it is used by
the transmitter as a reference at level measurements.
A missing reference pulse might be a symptom of a malfunctioning transmitter. Contact your local
Emerson Automation Solutions representative for assistance.
Product surface. This pulse is caused by a reflection on the product surface.
Different amplitude thresholds are used to filter out unwanted signals and pick up different pulses. The
transmitter uses certain criteria to decide which type of pulse that is detected.
Echoes found above the Surface Threshold might be considered the product surface.
Surface threshold. The amplitude threshold used for detecting the product level peak. The amplitude
threshold is designed as a number of individually adjustable amplitude threshold points, the ATC. See
"ATC" on page
The ATC is set during the Measure and Learn function and can be adjusted manually. The ATC is used for
filtering out disturbances with an amplitude smaller than the product surface echo.
The surface thresholds should be set to approximately 20 percent of the measured signal amplitude of
the product surface.
False echo area. False Echo Areas are set during the Measure and Learn function (see
page
adjusted manually.
162
Reference
Hold off
distance
110.
117), when the disturbing object is larger than the surface echo. The False Echo Area can be
False echo
Unknown
Reference Manual
00809-0100-4026, Rev KC
Product
surface
Surface threshold/ATC
"Guided setup" on
Service and Troubleshooting
Tank
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