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Author: Site Editor Publish Time: 2026-01-15 Origin: Site
Introduction: Are you missing 90% of the information your instrument sends?
In operating radar level gauges, most users only focus on one final result: the percentage or millimeter value of the level. However, behind this simple number, the instrument performs thousands of complex measurements per second, presenting you with a complete and original "operating condition map"—the echo curve.
Ignoring the echo curve is like a doctor diagnosing a patient based solely on a thermometer reading, refusing to look at an X-ray. When you learn to interpret it, you will gain:
The ability to anticipate problems: Detecting signal attenuation trends before antenna contamination.
Precise Adjustment Basis: No longer blind trial and error, but targeted parameter adjustments.
Root Cause Insight: Instantly distinguish between instrument malfunction, installation issues, and process changes.
Today, we will make this mysterious "waveform graph" clear and easy to understand.
Part 1: What is an Echo Curve? Basic Elements Explained
A radar level gauge emits microwaves into the tank and receives all reflected signals. The echo curve graphically displays the relationship between the "intensity" of all reflected signals and their "distance (corresponding liquid level)."
Horizontal Axis (Distance/Liquid Level): From left to right, represents the distance from the end of the instrument antenna (zero point) towards the bottom of the tank. The far right is usually the set full-scale position.
Vertical Axis (Signal Strength): From bottom to top, represents the strength of the reflected signal, usually measured in dB.
Remember Three Key Concepts:
Peak: The "peak" on the curve. A high and steep peak usually represents a strong reflecting surface.
Noise: Irregular, fine fluctuations at the bottom of the curve. Ideally, background noise should be low and flat.
Threshold: A settable horizontal reference line. The instrument will only track peaks with signal strength exceeding this threshold; this is a crucial "filter" for locking onto the true liquid level.
Part Two: How to "Read" Curves Like an Expert? Analysis of Six Typical Curves
Please save this "visual dictionary" for quick comparison when you see curves.
Scenario 1: "Healthy Curve" under Ideal Operating Conditions
Description: An isolated, steep, and towering main peak appears against a flat, low-noise background. The position of the main peak clearly corresponds to the current liquid level.
Interpretation: Good medium reflection (high dielectric constant), calm liquid surface, no strong interference, clean antenna, and correct installation.
Action Guide: This is the commissioning target. The instrument will automatically and easily lock onto this peak.
Scenario 2: "Low Dielectric Constant" or "Low Liquid Level" Curve
Description: The main peak is noticeably shorter but still clearly discernible, with a sharp shape. Background noise remains relatively unchanged.
Operating Condition Interpretation: The medium has weak reflectivity (e.g., liquefied gas, solvent), or the liquid level is very low. This is not a malfunction! It's a normal physical phenomenon.
Action Guidelines: Lower the "signal threshold" to ensure the instrument can "see" this weak signal. For media with consistently low dielectric constants, consider guided wave radar.
Scenario 3: "Multi-peak Competition" Curve (Interference Curve)
Characteristic Description: Multiple competing peaks of similar height appear. The actual liquid level peak may not be the highest one.
Operating Condition Interpretation: A strong interference source exists within the tank: such as vigorous agitation, feed impact, or a foam layer. The instrument may jump between several peaks, causing unstable displayed values.
Action Guidelines:
Observe the process status to determine the interference source.
Enable stronger signal filtering or "agitation mode".
If it is a fixed interference (e.g., tank wall reflection), use the false echo suppression function to mask the peak at the fixed location.
Scenario 4: "Antenna Contamination or Scabbing" Curve
Description: The entire curve "collapses," with all signal amplitudes (including noise) drastically reduced, and the true liquid level peak becomes very short or even difficult to discern.
Interpretation: The antenna transmitting/receiving surface is covered with crystals, viscous media, or condensation, severely attenuating the microwave signal.
Action Guide: Plan to clean the antenna immediately! This is a direct signal for preventative maintenance. For conditions prone to crystallization, choose a planar antenna and consider adding protective measures.
Scenario 5: "Connector (Waveguide) Effect" Curve
Description: Near the far left of the graph (near the antenna), a very tall and sharp "initial peak" appears, followed by the true liquid level peak.
Interpretation: The instrument has a long connector or waveguide installed, and reflections from the bottom of the tube create this extremely strong, fixed interference.
Action Guide: The "False Echo Suppression" function must be used to shield the signal in this fixed area; otherwise, the instrument will incorrectly lock onto this initial peak.
Scenario 6: "In-Tank Structural Interference" Curve
Morphological Description: In addition to the true liquid level peak, fixed, unchanging "ghost peaks" appear at specific distances.
Operating Condition Interpretation: These are reflections from fixed obstacles inside the tank (heating coils, ladders, support beams).
Action Guide: Perform commissioning in an empty tank state, learn the location of these fixed false echoes, and set a suppression zone; the instrument will ignore them in measurements.
Part Three: Practical Three-Step Method—Using Echo Curves to Handle Commissioning and Diagnosis
Step 1: Empty Tank Learning
Ensure the tank is empty and access the instrument's commissioning/echo curve interface.
Observe the curve, identify and record all fixed peaks (initial connection peak, structural interference peak).
Use the "False Echo Suppression" function to lock or block the distance area where these fixed peaks are located.
Step 2: Material-Loaded Verification and Locking
Start feeding and observe the curve.
Find a dynamic peak that steadily moves to the right as the liquid level rises; this is the true liquid level peak.
Fine-tune the "signal threshold" to just below the bottom of this dynamic peak to ensure the instrument can stably track it.
Step 3: Health Monitoring and Trend Analysis
Regularly (e.g., monthly) access the interface to save or view the echo curves of key instruments.
Pay attention to the peak height: A sustained, slow decline may indicate the antenna may need cleaning.
Pay attention to noise levels: An overall increase may indicate new electrical interference or instrument hardware problems.
Hebei Jubo Intelligent Diagnostic Platform: Making Curve Interpretation "Zero-Threshold"
We make advanced technology easier to use:
Intelligent Curve Analysis Assistant: Upload your echo curve screenshot to our debugging software or cloud platform. The AI engine will automatically analyze and provide possible problem diagnoses and optimization suggestions.
Interactive Online Training Module: Visit our learning center and use the interactive echo curve simulator based on real-world cases. Drag and drop parameters to observe curve changes in real time, quickly improving your graph reading skills.
Expert Online Support: During debugging or troubleshooting, you can share real-time curves with one click through the app. Our engineers will annotate and explain online, providing "face-to-face" guidance.
Starting today, let your instruments speak to you honestly.
Echo curves are the most direct dialogue between your instruments and yourself. Mastering this language will give you unparalleled confidence and control over the measurement status of your storage tanks. This is not just an improvement in technical capabilities, but a fundamental leap from passive maintenance to proactive management.
[Download "Radar Level Gauge Echo Curve Full-Scenario Interpretation Atlas and Practical Manual" Now]
(Link to a beautifully designed PDF containing high-resolution illustrations of all curves in this article and a diagnostic checklist)
[Upload a screenshot of your perplexing echo curve to get free AI intelligent analysis and expert review]
(Link to a simple image upload and analysis result generation page)
