Displacement sensor, also known as linear sensor, is a linear device belonging to metal induction. The function of the sensor is to convert various measured physical quantities into electricity. In the production process, the measurement of displacement is generally divided into two types: measurement of physical size and mechanical displacement. Displacement sensors can be divided into two types: analog and digital according to the transformation of the measured variable. The analog type can be divided into physical type and structural type. Commonly used are analog structure types, including potentiometer displacement sensors, inductive displacement sensors, self-aligning machines, capacitive displacement sensors, eddy current displacement sensors, and Hall displacement sensors. An important advantage of digital displacement sensors is the ease of feeding the signal directly into a computer system. This kind of sensor develops rapidly and is widely used.

　　The working principle of the straight line is the same as that of the sliding rheostat, which is used as a voltage divider, and the displacement sensor (Fig. 5) presents the actual position of the measured position with the relative output voltage. There are the following requirements for the work of this device: 1. If the electronic ruler has been used for a long time, and the seal has aged, there are many impurities mixed in, and the water mixture and oil will seriously affect the contact resistance of the brush, so It will make the displayed number jump continuously. At this time, it can be said that the electronic ruler of the linear displacement sensor has been damaged and needs to be replaced.

　　2. If the capacity of the power supply is small, many situations will occur, so the power supply needs to have sufficient capacity. Then, the lack of capacity will cause the following situations: the movement of the melt glue will change the display of the mold clamping electronic ruler, and there will be fluctuations, or the movement of the mold clamping will cause the display of the injection electronic ruler to fluctuate, resulting in a large error in the measurement results. If the driving power of the solenoid valve is connected with the power supply of the linear displacement sensor at the same time, the above situation is more likely to occur. In serious cases, the voltage range of the multimeter can even measure the relevant fluctuation of the voltage. If the situation is not caused by high frequency interference, electrostatic interference or insufficient neutrality, then it may be caused by the power of the power supply being too low.

　　3. Frequency modulation interference and electrostatic interference may cause the digital display of the electronic ruler of the linear displacement sensor to jump. The signal line of the displacement sensor (Figure 6) should be separated from the strong current line of the device. The electronic ruler must use a grounding bracket compulsorily, and at the same time make the housing of the electronic ruler in good contact with the ground. The signal line needs to use a shielded line, and a section of the electric box should be grounded with the shielded line. If there is high-frequency interference, the voltage measurement using a multimeter will usually display normal, but the displayed number will keep beating; and when there is electrostatic interference, the situation is the same as that of high-frequency interference. To prove whether it is electrostatic interference, you can use a power cord to short-circuit the cover screw of the electronic ruler with some metal on the machine. As long as it is short-circuited, the electrostatic interference will be eliminated immediately. of. However, if you want to eliminate high-frequency interference, it is difficult to use the above method. High-frequency interference often occurs in inverter power savers and robots, so you can try to stop the high-frequency power saver or robot to verify whether it is high or not. frequency interference.

　　4. If the electronic ruler of the linear displacement sensor is working, the displayed data at a certain point beats regularly, or when there is no data displayed, it is necessary to check whether the insulation of the connecting wire is damaged. , and a short circuit to ground caused by regular contact with the casing of the machine.

　　5. The voltage of the power supply must be stable. The industrial voltage needs to meet the stability of ±[%]. For example, if the reference voltage is 10V, the fluctuation of ± can be allowed. If not, it will cause the displayed trap to fluctuate. such a situation. Displacement sensor (Figure 7), but if the amplitude of the displayed fluctuation at this time does not exceed the amplitude of the fluctuation of the fluctuating voltage, then the electronic ruler is normal.

　　6. The alignment of the installed linear displacement sensor needs to be good, but the parallelism can allow ± error, and the angle can allow ± 12° error. However, if the parallelism error and the angle error are too large, there will be a situation where the displayed number jumps. Then when such a situation occurs, the parallelism and angle must be adjusted.

　　7. During the connection process, you must pay more attention. The three wires of the electronic ruler cannot be connected wrongly, and the power wire and the output wire cannot be exchanged. If the above line is connected incorrectly, there will be a large linear error, it will be difficult to control, the control accuracy will also become very poor, and the display is prone to beating and so on.