Why does the short-range 80G radar read the wrong distance and throw error codes?

Model: JJY-YGD38M-18L — 80 GHz short-range radar level transmitter

Symptom

The customer needed the radar to measure correctly at an actual distance of about 0.12 m. With the radar lifted away from the target the reading was about 0.25 m, and in some cases an abnormal error code was output. During testing, even after lifting the sensor the reported distance was still around 0.11 m — far from the real value.

Root cause

In this very short measuring range the true surface echo competes with antenna and tank-wall spurious echoes. Without proper false-echo learning the unit locked onto a wrong echo.

Fix

Upgrade the firmware to the 0901 build and perform false-echo learning. After that the unit met the customer’s requirement; the remaining units are being upgraded and re-tested.

False-echo learning commands:

• AT+FALSEECHO=2,0.12,0.18 — learn false echoes in the range 0.12–0.18 m (effective suppression).
• AT+FALSEECHO=1 — enable false-echo learning.
• AT+FALSEECHO=0 — disable false-echo learning.
• AT+FALSEECHO=3 — clear the learned false echoes.
• AT+FALSEECHO=2,a,b — learn false echoes in the distance range [a, b].

Also check and adjust the installation position.

Related reading

• Difficult Tanks & Special Applications Guide
• Why is the 1.5-inch 80G radar level reading inaccurate for grain, and which parameters fix it?
• Why does the M38 threaded radar read 1105 mm when the actual level is 510 mm inside a narrow pipe?
• Why does the 80G short-range radar produce messy echoes and false readings in a small closed metal tank?

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