Repair of inaccurate display fault of Yaohua brand electronic weighing scale in Binhai New Area

Repair of inaccurate display fault of Yaohua brand electronic weighing scale in Binhai New AreaThe introduction is as follows:

In the industrial logistics field of Binhai New Area, Yaohua brand electronic weighing scales are key measuring equipment, and their display accuracy directly affects cargo settlement and production safety. However, due to environmental factors, equipment aging, and improper operation, inaccurate display has become a common malfunction. This article combines practical maintenance cases to systematically analyze the causes of faults and maintenance strategies, providing standardized operation guidelines for technical personnel.

1、 Fault Symptoms and Preliminary Diagnosis

Inaccurate display is usually manifested as weight value jumping, abnormal zeroing, or excessive bias load error. A 100 ton weighing scale of a logistics enterprise once experienced fluctuations in the number between 85-95 tons during weighing. After partial load testing, it was found that the output signal of the southwest corner sensor was abnormal, and it was initially identified as a sensor or signal transmission failure. Technicians need to first conduct a visual inspection: confirm that there are no foreign objects stuck on the scale body, that the bolts have not touched the scale body, and that the limit clearance meets the standard (usually 2-3mm). At the same time, check whether the grounding wire is loose and causing electromagnetic interference.

2、 Deep maintenance of core components

1. Sensor system troubleshooting

Sensor failures account for over 60%, and common issues include:

-Mechanical damage:Repair of inaccurate display fault of Yaohua brand electronic weighing scale in Binhai New AreaCheck if the sensor deformation beam has deformed due to overload. In a certain case, the elastic body of the sensor cracked due to long-term overload of the weighing scale and needs to be replaced as a whole.

-Electrical fault: Use a multimeter to detect the excitation voltage (normal 10V ± 0.1V) and signal output (mV level). If the voltage fluctuation exceeds 5%, check the power supply line. During a repair, it was discovered that the sensor cable had signal interruption due to rodent bites. After re soldering, it was restored.

-Sealing failure: If the sealing ring of an IP68 protection level sensor ages, rainwater infiltration can cause zero drift. Disassemble the sensor, clean the interior with alcohol, replace the sealing ring, and dry it for 48 hours.

2. Optimization of signal transmission system

Signal line breakage is the second major source of failure, and maintenance points include:

-Junction box handling: Open the junction box to check if the terminals are oxidized. In a certain case, the contact resistance increased due to water ingress into the junction box. After cleaning, seal the interface with a heat shrink tubing.

-Cable replacement: Four core shielded cables are used, wired according to red (excitation+), black (excitation -), green (signal+), and white (signal -) standards, and the shielding layer is grounded at one end. After replacement, a linearity test is required to ensure that the error is less than or equal to 0.05% FS.

3. Display instrument calibration

Instrument malfunctions are often manifested as crashes or displaying garbled characters. Maintenance process:

-Hardware testing: Check if the capacitor on the power board is bulging. During a repair, it was found that the 1000 μ F/35V capacitor failed, causing unstable voltage. After replacement, it was restored.

-Software reset: For the XK3190 series instrument, press and hold the 'Zero'+'Peel' button to turn on the machine, enter the calibration menu and enter the standard weight (recommended to use 80% of the full range weight), repeat three times and take the average value.

3、 Construction of preventive maintenance system

1. Environmental control: Install rain shelters around the scale body to prevent direct sunlight from affecting accuracy due to thermal expansion and contraction. After a certain enterprise installed a sunshade, the weighing error in summer decreased from 0.3% to 0.1%.

2. Regular calibration: It is recommended to adjust the four corner error once every quarter by fine-tuning the potentiometer inside the junction box to ensure that the error at each point is less than or equal to 0.1% FS.

3. Spare parts management: Establish inventory of key components such as sensors and junction boxes. Original sensor models from Yaohua, such as XH-30T, should be labeled with the production date and priority should be given to using spare parts within their shelf life.

4、 Typical Case Analysis

In 2025, a chemical enterprise in Binhai New Area experienced a fluctuation fault in the weighing scale display. After investigation, the maintenance team found that:

1. Intermittent short circuit caused by wear of sensor cable at the conduit;

2. The reference voltage of the instrument A/D converter is offset by 0.2V;

Solution:

-Replace shielded cables and add rubber sheaths;

-Adjust the reference voltage of the instrument to 2.5V ± 0.01V;

-After recalibration, conduct 20 repeated tests with a standard of less than or equal to 0.02%.

Through systematic fault diagnosis and standardized maintenance processes, the maintenance cycle of Yaohua weighbridge can be shortened from an average of 72 hours to 24 hours, with high measurement accuracy.