Electronic hooks describe common faults and processing methods. With the continuous development of electronic technology, the accuracy of measurement work is closely related to the economic benefits of enterprises. As a measurement instrument that is accurate in measurement, fast in weighing, and easy to use, electronic trucks are Weighing and metering plays a vital role. It is the first hurdle for internal logistics turnover and foreign trade. However, due to the high frequency of use of electronic truck scale, poor use of the environment, coupled with improper use, it is inevitable that such failures, to my years of experience in the verification, maintenance of scales, a brief analysis of the electronic truck scale common faults and troubleshooting methods.

First, the working principle of the electronic hook is said by the weighing display instrument, weighing sensor, junction box, weighing platform and other components, is the weight of the weighing platform under the influence of gravity generated by the sensor bridge output and called The analog signal with a proportional value is magnified by the instrument filter, and the conversion becomes a reading to the instrument window.

Second, failure analysis and processing Electronic hook said that when the failure, we must first find the fault site. Fault location is generally two major parts: First, the display instrument, and second, the scale body. The simplest method is to use the simulator to distinguish whether the fault is coming from the instrument or the scale body. Use the following method: Unplug the signal cable plug behind the weighing indicator, insert the simulator plug, turn on the instrument power supply, and observe whether the instrument is powered normal work. If it works normally, it means that there is no problem with the weighing indicator and the fault is in the scale body or junction box; if it is not working properly, it indicates that the fault is in the weighing indicator or power supply part; if the weighing platform is faulty, the limit device can be checked first. There are two kinds of horizontal and vertical limit devices, check whether the limiting device limit spacing is reasonable, the general distance is adjusted to 2mm ~ 3mm. Subsequent step-by-step checks:

(1) Junction box, now check the junction box has water vapor intrusion, if there is water vapor with alcohol scrubbing, then blow dry with a hair dryer; search for wiring for short circuit, at the same time check the wires and ground or signal cable outer stainless steel shield wire No leakage and short circuit.

(2) sensor, find the sensor fault is as follows: in the junction box with a multimeter to check the positive and negative excitation resistance between the resistance, the resistance is approximately 400Ω / number of sensors, with a multimeter to measure the total output of the positive output and negative output between Resistance, its resistance is approximately 250Ω/number of planes. If you find that the resistance is incorrect, press Next to continue to search and disconnect the sensor one by one. Use the method described above to measure the impedance between the positive and negative output terminals of the positive and negative excitation terminals and investigate the damaged sensor. If there is no problem with this step, then press step to continue searching. Place the weights on the sensor corners of each section of the weighing platform in order and find the +si and -si terminals of the bad sensor or disconnection sensor. The measured resistance value should be around 350Ω.

Third, the electronic hook case case one, a 30-ton electronic truck scale weighing error was found when the load is large, the material on the platform is not where the weight difference shows 200kg or so, and the repeatability is poor, the same One of the cars was put on two pounds, resulting in an error of 60kg. Failure analysis: This phenomenon is obviously the cause of the scale body. The focus of the inspection is on the balance of the scale body, whether the limit device is against the scale body and whether the sensor is damaged. After checking the scale under the body and around without foreign matter, the limit device is normal. Further inspect the sensor to measure the resistance of the four sensors are within the normal range, the output voltage is also normal, with a 20-ton weight measured eccentric load showed an angle of 119,620 kg, the adjacent three corners were: 219940 kg 319980 kg 419980 kg This judges that the 1 angle sensor is damaged, and after replacing the angle sensor, it is said to return to normal.

Case II. A 50-ton electronic truck scale. There are often signs that the signal is sometimes interrupted and sometimes good, and the meter indicates that the car has a wrong or under-loaded sign when it is on a weighing platform. Failure analysis: After eliminating external environmental factors, check the signal cable, because the display instrument and scale are connected by a seven-core shielded cable, which will always supply power to the load cell and transmit the output signal of the sensor junction box to Instrument, inspection found that the signal line connected to the instrument was bitten by rats, intermittently connected, when the car vibrates when the pound, the meter will be shown inaccurate. Cut the end of the cable and re-strip the welding signal cable connector. Troubleshooting, the scale returned to normal.

Case 3: A 60-ton electronic truck scale instrument shows that the unstable display value is beating, and when the same vehicle is weighed, the same material is weighed many times and the results are inconsistent.

Failure analysis: first check the external environment, whether there is debris, limit is too small. After everything is fine, dial the plug of the signal cable behind the meter and connect it to the simulator. The meter is working properly. It shows that there is no problem with the instrument and the fault is in the scale body. Check the connector of the signal wire and the connector in the terminal box. No problem. Do not suspect the fault. The output voltage of the load cell is normal. Use the detachment method, open the terminal box, and disconnect one by one. The connecting lines of sensors No. 1 and No. 6 were found to be broken when they were separated from the No. 3 sensor angle. After replacing the sensor, the scale returns to normal.

The electronic hooks indicate that the causes of the malfunctions are various. As long as the failures are carefully analyzed and judged during the inspection, the patient inspection tests will be solved. The maintenance of the truck scale is very important. Every day, check whether there is any debris in the scale platform, bottom of the scale and the surrounding of the scale to withstand the scale body. Check whether the limit clearance is normal or not. Check the replacement of the terminal box desiccant regularly, especially if the load cell is As the heart of the electronic scale, its performance largely determines the accuracy and stability of the electronic scale. It is forbidden to use electric welding on the weighing platform to avoid burning the sensor and bring unnecessary loss to the company. In short, as long as diligent in inspection, timely detection and resolution. The weighing system of the weighing instrument will be in a good state and its accuracy is completely reliable.