Specifications

Table Of Contents
132
Reference Manual
00809-0100-4026, Rev HA
Section 7: Service and Troubleshooting
November 2014
Service and Troubleshooting
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 troubleshoot-
ing. 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 Process Management 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 84.
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.
Reference
Product
surface
Unknown
Hold off
distance
Ta nk
bottom
False echo
Surface threshold / ATC