Electronic platform scale: how to deal with several common faults of electronic platform scale

The electronic platform scale is a movable electronic scale with a platform-shaped carrier, weighing less than 3 tons, and it is a very widely used electronic weighing instrument. Small weighing electronic platform scales usually use only one load cell to support the weighing platform, while electronic platform scales weighing more than 1 ton often require multiple load cells to support the weighing platform through a certain mechanism . As the working environment of electronic platform scales is more complicated, the repairs caused by improper use and lack of necessary maintenance are also increasing day by day. For this reason, the author sorted out the common fault phenomena and solutions in the work to communicate with colleagues. 1 When no load acts on the electronic platform scale, the displayed value is not zero, and the value is slowly changing. The reasons for this failure are: (1) The glue is opened at the place where the resistance strain gauge is pasted on the load cell; (2) Weighing A certain bridge arm of the sensing bridge has the phenomenon of virtual welding; (3) The insulation resistance value between the weighing sensing bridge and the elastic body decreases. 2 The weighing indication of the electronic platform scale is inaccurate. The reasons for this failure are: the elastic body has been hit, causing stress in the elastic body, and even the elastic body is partially broken. In this way, when the load is applied to the elastomer, the strain generated by the elastomer is not linear, causing inaccurate readings; the use of electronic floor scales in high temperature and high humidity environments causes the insulation resistance between the strain bridge and the elastomer to decrease. ; Excessive fatigue of the elastomer causes the elastomer to lose its due stress variation range. 3 When the same load is applied to the electronic floor scale, the indications are different several times, that is, the repeatability is out of tolerance. The reasons for this failure in the construction of the electronic floor scale are: (1) The characteristics of the resistance strain gauge itself are not good; (2) The elastomer The material and geometry are not good; (3) The adhesive is deteriorated, and the strain gauge and the elastomer are not stuck well. The above-mentioned failures are all caused by fatigue and damage of the component elastomers and resistance strain gauges in the load cell. During maintenance, first check the appearance of the load cell. If you look at how the resistance strain gauge is attached, observe whether there is open welding or virtual welding at the welding point of the strain bridge and the compensation element, and whether there are collision marks on the elastic body. If there are traces of partial fracture, perform symptomatic treatment according to the appearance inspection; secondly, perform a performance test to check the resistance value of the resistance strain gauge. The resistance value is about 250-500 ohms, and the resistance value of the bridge arm should be consistent. , Under the power-on condition, to test the bridge power supply, the voltage of the bridge power supply is required to be accurate, because when the stability of the power supply is not good, it is easy to produce zero drift. 4 After the electronic platform is turned on for a period of time, the zero point or digital display during weighing is unstable, and the reasons for this failure are: (1) The power supply voltage is unstable or the signal, especially the feedback line, is poorly connected. Voltage power supply solution. (2) The system is poorly grounded, and the grounding of the electronic scale is very important, especially the instrument shell must be equipped with protective grounding and electrostatic discharge grounding. Generally, the ground wire of a good quality single-phase three-hole socket can be used to achieve grounding, and a separate power supply should be installed.的地线。 The ground wire. (3) External electromagnetic interference, the main reason is that the electronic platform scale power supply system is connected with the power supply system of the large-scale power equipment in the enterprise factory, so that when the power equipment is running, the electronic platform scale display data will be bounced, thereby affecting the accuracy of the value And stability. Electronic floor scales can only use a single lighting power supply, and it is strictly forbidden to lead from three-phase four-wire, and there is no interference equipment in the same power supply. (4) The inside of the junction box is damp or the skin of the sensor cable is damaged. At this time, you can open the junction box, wipe the junction box with alcohol, dry the junction box with a hair dryer, and connect the damaged cable (especially the shielding net) , Wrap the outside with waterproof insulating tape. (5) Touch the electronic floor scale display shell with your hands, and it will feel hot. There are two situations: (1) The meter itself heats up, regardless of the season, because of the inferior display, connectors, sensors, and its own circuit design. Unreasonable, the quality of electronic components is inferior, moisture-proof, and the insulation performance is poor. This kind of electronic platform scale is generally produced by small factories. For electronic platform scales that work near the heat source, heat insulation measures should be taken. If possible, the electronic platform scale display should be placed in an air-conditioned room. If this condition cannot be met and the electronic platform scale must be placed in a high-temperature environment, select When buying an electronic floor scale, you should pay attention to the temperature compensation range of its sensor, and choose sensors with a large temperature compensation range. In short, the heating phenomenon of electronic platform scales depends on the user's correct selection, reasonable installation and use, and also expects manufacturers to rely on scientific and technological means to improve the performance of electronic platform scales. 5 There is a heavy object on the electronic platform scale, and the display is still zero. The reasons for this failure are: (1) The function keys of the weighing instrument of the electronic platform manufacturer are used incorrectly and are not in the weighing display state; (2) Weighing The total output line of the sensor is not in contact with the connector of the display instrument. The above situations can be eliminated by carefully reading the manual and checking carefully, and correct operation. There are many repair methods for electronic platform scales, such as observation method, elimination method, substitution method, etc. Some good methods depend on continuous summarization and accumulation in practice. As long as they are diligent in checking and finding solutions in time, the weighing system of the electronic platform scale will be in a good condition and its accuracy is completely reliable.