​ Common problems and solutions in the calibration of sonar-type external level gauges

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Sonic external level gauges are being used more and more widely. During the process of installation and adjustment, some problems may arise. To address these issues, the engineers at Dinghua Electronics are here to help solve them. Come and learn more: Phenomenon 1: The sonic external level gauge displays two dashes “--”. Cause: This usually occurs while entering a password in the P… mode, indicating that the password entered is incorrect. Solution: Re-enter the correct password. Phenomenon 2: The instrument displays a moving “-” or a fixed “-” for an extended period; there are pauses during the self-check and optimization process (or it remains at a certain value), preventing the optimization from being completed within 90 seconds. Reason: The signal is too weak or absent. Troubleshooting method: 1. No action is taken when the tank is empty or in a blind area ； 2. Check whether the wiring of the level sensor is correct ； 3. Check whether the parameters match the operating condition information ； 4. Reposition the level probe. 3. How to determine whether the measurement probe is functioning properly? 3.1. The resistance of the probe’s positive and negative terminals should be 400 KΩ ±5%; if it is not within this range, it indicates a hardware fault with the probe. 3.2. Remove the probe, bring your ear close to the probe core; a clicking sound is heard when the probe is in operation. 4. How to determine whether the host hardware is functioning properly? The normal current of the entire host is within the range of 110–170mA; otherwise, it is considered that there is a problem with the host’s hardware. 5. How to deal with display deviations on the instrument? 5.1. If it is a fixed deviation, adjust the migration amount (parameter 3) according to the actual deviation size. 5.2. If it is a non-fixed deviation, such as a low liquid level resulting in a small deviation and an increased liquid level leading to a larger deviation, first modify the liquid property coefficient (parameter 6#). It is necessary to raise the liquid level above the calibrated probe, and the instrument will automatically calibrate itself. 5.3. Remote transmission deviation: This refers to the situation where the display on-site is accurate, but there is a deviation in the display in the control room. It is usually caused by differences in range settings. It is necessary to verify whether the range settings are consistent. 5.4. Level doubling: The level gauge shows the level as an integer multiple of the actual level, usually twice; for example, if the actual level is 1 meter, the gauge will display around 2 meters. This situation generally occurs during the feeding of empty tanks or when the liquid level is low. Issues that occur during feeding can be resolved using the instrument’s automatic reset function; manual reset can also be performed if necessary. If doubling occurs at a low position and manual reduction is ineffective, try changing the probe installation location.