Digestive Malt Extract,Malt Extract,Natural Malt Extract,Healthy Malt Extract NANJING ZELANG MEDICAL TECHONOLOGY CO., LTD , https://www.hawfitness.com I. Overview
With the rapid development of science and technology, electronic weighing instruments occupy a position that cannot be ignored in production and management. In order to make better use of their role, they must ensure their reliability and measurement accuracy. However, whether it is a newly installed electronic weighing instrument or an electronic weighing instrument that has been used for many years, some malfunctions may occur, rendering them inoperable.
The faults of the electronic scale can be basically divided into two types: common faults and special faults. But no matter what type of fault, it is caused by several major aspects such as weighing display, load cell, power supply, connecting line and mechanical force transmission mechanism. The cause of the failure is caused by unreasonable installation design or improper use and natural damage. The following are some of the more special troubleshooting experiences we encountered in the installation and maintenance of electronic scales.
Second, the congenital deficiency of electronic weighing components
The electronic ground balance is an electronic weighing instrument that we use more than Zui, and has experience in molding during installation and debugging. However, once a steel billet scale was installed and commissioned at a rolling mill, there was a phenomenon that never happened. That is: after the installation is completed, the test weight is used for calibration, and it is found that the weight displayed by the display meter does not change according to the weight of the applied weight, but is suddenly smaller and smaller, and the quantity displayed by the meter is also placed with the weight. Related, so normal calibration is not possible.
The weighing sensor of the scale is connected in parallel. After careful inspection, the connection line of the sensor is correct (the sensor is connected according to the color code of the manual wiring diagram). There is no fault in the display instrument and mechanical parts. After careful analysis of the above phenomenon, we believe that the problem still appears on the sensor. In order to find out the reason further, we first calibrate the display instrument with the simulator, then connect the sensor, and then press the four corners of the scale with one weight. The result shows that the three corners display positive values ​​and the other corners display values. Is a negative value. Therefore, we conclude that the internal wiring of the sensor of the corner is incorrect. After the bridge voltage of the sensor or the positive and negative leads of the signal line are exchanged, the angle is also displayed as a positive value. Since the positive and negative poles of the inner lead of the bridge voltage or signal are reversed when the sensor is packaged at the factory, the above fault occurs when the connection is performed according to the normal color code during installation, and the connection is recalibrated after the connection is changed, and the above phenomenon is eliminated.
Another example is that in the overhaul of the truck scale, the scale cannot be operated normally after the four sensors and the sensor junction box are replaced (the display shows underload). Since the sensor and the junction box are newly purchased, when the cause of the fault is found, the connection line is mainly checked, but the connection line is not connected wrong, but when the ground line is disconnected, the display meter is displayed normally. The above fault occurs again after the ground line. Disconnect the display instrument, check the bus with a multimeter, and find that the signal positive pole is connected to the ground wire. Therefore, when the sensor bus is connected with the display instrument system, the signal positive pole and the bridge voltage negative pole are short-circuited, which destroys the normal working state of the sensor bridge, so the above occurs. phenomenon. Next, disconnect all the sensors and check the results are normal. The problem is that they appear in the sensor junction box. When checking the sensor junction box separately with a multimeter, find out that the ground terminal of the junction box is short-circuited with the signal positive terminal of the sensor in the junction box. Look carefully to find out that the printed circuit on the printed circuit board in the junction box is short-circuited. Where the problem is caused by the quality of the junction box. (After analysis, the junction box has not been carefully tested at the factory, otherwise the above problem should not occur). After the short circuit is cut off with a blade, the above troubleshooting is eliminated.
Third, the design and installation of unreasonable problems
The program-controlled hopper scale is the first application in our company. When we installed and commissioned two programmable hopper scales in the second electric furnace branch, we found that the two scales interfered with each other. The control system sometimes could not work according to the specified procedure, and often malfunctioned. The scale is set according to the design scheme of a design institute for the two batching systems of the second electric furnace branch. The above phenomenon occurred during installation and debugging. After repeated trials and analysis, we found out that the cause of the fault was a power supply problem. Because the control part and the instrument part of the two scales are connected to the lighting power supply, the control part is connected to the power supply, and the instrument part is still connected to the lighting power supply, solving the above problems, and completing the debugging work of the program-controlled hopper scale to ensure The normal operation of the loading system.
Two other 30t truck scales are installed and commissioned by a certain manufacturer. The installation was in the summer, but the scale was out of the winter after the winter. After we analyzed the cause, we found that the wiring methods of the two scales are all connected by the four-wire system. Since we are located in the northern alpine region, the temperature difference between winter and summer is large. We analyzed that the error is due to the change of the wire resistance with temperature. (The principle is slightly, another article is devoted to the discussion), we solved the problem after changing the four-wire system to the six-wire system.
Fourth, the failure occurred in use
Our non-foundation pit electronic truck scale has had such a problem in the winter: the weight of the display instrument is also inconsistent because the position of the stop is different after the car is weighed. When the car of known weight is put on the weighing platform, the position of the car is docked at the front position of the weighing platform, the weighing result is slightly higher than the actual weight, and when the second weighing is performed, it is stopped at the rear of the weighing platform. The weighing result is lower than the actual weight, so the scale cannot be normally measured. After careful inspection, the weighing indicator and the connecting line are normal. When the car is on the weighing platform, the scale body can be observed to see a weak swing, indicating that the scale body has no foreign matter stuck. After analyzing and judging that the end is lower than the actual weight, it is possible that there is a hard object on the ground at the bottom of the scale body to hold the scale body. The load cell is not subjected to the actual gravity, so the weight displayed by the meter is smaller than the actual weight. In order to confirm this judgment, we used iron hooks to reach the bottom of the scale body for inspection, and found that there was foreign matter on the scale bottom against the scale body. The foreign matter is a mixture of pulverized coal, dust, etc., which is blown into the bottom of the scale by the wind and mixed with rain and snow. When it is frozen, a hard mixture is formed against the scale body, which reduces the positive pressure on the two sensors at the end. The measurement data of the truck scale is inaccurate, and the scale is restored to normal after the foreign matter is removed.
In addition, the electronic scale often appears in the use of the instrument to display data instability (variables), the fault is caused by the deterioration of the instrument or sensor performance, but more because the wire box or wire connection is water, damp caused. However, the above phenomenon has not occurred in the electronic weighing instrument we used, but it is not caused by the above reasons. However, the strands of the welded portion of the connector connected to the junction box are damaged by the long-term corrosion of the residual oil, so that the multi-strand wire Break, only two or three strands of wire are left (it is hard to find on the outside). After we carefully searched, we found the above fault and re-connected to remove the fault.
V. Conclusion
The above-mentioned several faults are the special faults and processing experiences we have experienced in the installation and maintenance of electronic scales for many years. In order to ensure the normal use of electronic scales and better play their role in production and operation, it is necessary to continuously summarize and accumulate experience and timely eliminate various types of faults that occur during the installation and use of electronic scales.
Metering electronic scale special fault
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