Detection method of liquid level meter (magnetic flap liquid level meter)

　　Liquid level meter detection method:

　　1. Knocking and hand pressing method:
　　
　　It is common to encounter the phenomenon that the instrument runs well and sometimes badly. Most of this phenomenon is caused by poor contact or cold soldering. For this situation, the knocking and hand pressing method can be used. The so-called "knocking" is to gently knock the plug-in board or components of the magnetic flap level gauge
　　
　　with a small rubber hammer head or other knocking objects on the parts that may cause faults , to see if it will cause errors or shutdown faults. The so-called "hand pressing" is that when a fault occurs, turn off the power and press the plugged components, plugs and sockets again with your hands, and then turn on the machine to see if the fault can be eliminated. If it is found that it is normal to knock the casing once, but it is not normal again, it is best to re-insert all the connectors and try again. If you are worried and unsuccessful, you have to find another way. 　　2. Observation method: 　　Use vision, smell, and touch. Sometimes, damaged components will change color, bubble or have burnt spots; burnt devices will produce some special smells; short-circuited chips will get hot; the cold soldering or desoldering of the magnetic flap level gauge can also be observed with the naked eye. 　　3. Elimination method: 　　The so-called elimination method is a method of determining the cause of a fault by plugging in and out some plug-in boards and devices in the machine. When the instrument returns to normal after a plug-in board or device is removed, it means that the fault occurred there. 　　4. Replacement method 　　: It requires two instruments of the same model or sufficient spare parts. Replace a good spare part with the same component on the faulty machine to see if the fault is eliminated. 　　5. Comparison method: 　　It requires two instruments of the same model, and one of them is operating normally. To use this method, you must also have the necessary equipment , such as a multimeter, oscilloscope, etc. According to the nature of the comparison, there are voltage comparison, waveform comparison, static impedance comparison, output result comparison, current comparison, etc. 　　The specific method is: let the faulty magnetic flap level meter and the normal instrument run under the same conditions, and then detect the signals of some points and compare the two groups of signals measured. If there is a difference, it can be concluded that the fault is here. This method requires maintenance personnel to have considerable knowledge and skills. 　　6. Temperature rise and fall method 　　Sometimes, the instrument will fail when it works for a long time or when the working environment temperature is high in summer. It will be normal when it is turned off and checked. It will be normal when it is turned on again after a while, but it will fail again after a while. This phenomenon is caused by the poor performance of individual ICs or components, and the high temperature characteristic parameters cannot meet the index requirements. In order to find out the cause of the failure, the temperature rise and fall method can be used. 　　The so-called cooling means that when the failure occurs, use cotton fiber to wipe anhydrous alcohol on the part where the failure may occur to cool it down and observe whether the failure is eliminated. The so-called heating means artificially raising the ambient temperature, such as putting an electric soldering iron close to the suspicious part (note that the temperature must not be raised too high to damage the normal device) to see if the failure occurs. 　　7. Shoulder riding method 　　The shoulder riding method is also called the parallel method. Put a good IC chip on the chip to be checked, or connect good components (resistors, capacitors, diodes, transistors, etc.) in parallel with the components to be checked to maintain good contact. If the failure comes from the internal open circuit or poor contact of the device, this method can be used to eliminate it. 　　8. Capacitor bypass method 　　When a circuit produces a strange phenomenon, such as a chaotic display, the capacitor bypass method can be used to determine the circuit part that is probably faulty. Connect the capacitor across the power supply and ground of the IC; for transistor circuits, connect it across the base input or collector output, and observe the effect on the fault phenomenon. If the capacitor bypass input is ineffective and the fault phenomenon disappears when bypassing its output, it is determined that the fault occurs in this level of circuit.