Linear displacement sensor working principle and troubleshooting methods
January 28, 2021
The working principle of the linear displacement sensor is the same as that of the sliding varistor. It is used as a voltage divider and it shows the actual position of the measured position with relative output voltage. There are the following requirements for the operation of this device:
First, if the electronic ruler has been used for a long time, and the seal has been aged, mixed with a lot of impurities, and the water mixture and oil will seriously affect the brush's contact resistance, so that the displayed figures will constantly jump. At this time, it can be said that the electronic scale of the linear displacement sensor has been damaged and needs to be replaced.
Second, if the capacity of the power supply is very small, there will be many situations. Therefore, the power supply needs sufficient capacity. Then, if the capacity is insufficient, the following situation will occur: the movement of the melted plastic will cause the display of the molded electronic ruler to change, and there will be fluctuations, or the movement of the mold clamping will fluctuate the display of the ejected electronic ruler, resulting in a great error in the measurement result. If the drive power of the solenoid valve is at the same time when the power supply of the linear displacement sensor is at the same time, the above situation is more likely to occur. When the situation is serious, the voltage of the multimeter can even measure the fluctuation of the voltage. If the situation is not due to high-frequency interference, static interference, or neutrality is not good enough, then it may be caused by the power of the power supply is too small.
Third, FM interference and static interference may cause digital displacement of the digital scale of the linear displacement sensor. The signal line of the electronic ruler should be separated from the strong electrical line of the device. The electronic ruler must use the grounding bracket forcibly. At the same time, the electronic ruler's housing should be in good contact with the ground. The signal line needs to use shielded wire, and a section of the box should be grounded with the shielded wire. If there is high-frequency interference, usually using a multimeter's voltage measurement will show normal, but the display number will be beating constantly; and in the case of static interference, the same situation occurs with high-frequency interference. To prove whether it is an electrostatic disturbance, you can use a power cord to short-circuit the electronic ruler's capping screw to some metal on the machine. As long as it is shorted, the electrostatic interference will be eliminated immediately. of. But if you want to eliminate high-frequency interference it is difficult to use the above method, Frequency Inverters and robots often appear high-frequency interference, so you can try to use the method to stop the high-frequency power saver or robot to verify that it is not high Frequency interference.
4. If the electronic scale of the linear displacement sensor is in the course of working, if the displayed data at a certain point regularly jumps or no data is displayed, it is necessary to check if the insulation of the connecting wire is damaged. , and short circuit to ground caused by regular contact with the outer shell of the machine.
Fifth, the power supply voltage must be stable, industrial voltage needs to meet the stability of ± 0.1 [%], for example, the reference voltage is 10V, you can allow fluctuations of ± 0.01V, if not, it will cause display The traps fluctuate in such situations. However, if the amplitude of the display fluctuation at this time does not exceed the fluctuation amplitude of the fluctuation voltage, then the electronic scale is normal.
6. The alignment of the linear displacement sensor needs to be very good, but the parallelism can tolerate an error of ±0.5mm, and the angle can tolerate an error of ±12°. However, if the parallelism error and the angle error are both too large, this will cause the display of digital jitter. When such a situation arises, it is necessary to adjust the degree of parallelism and angle.
7. During the process of connection, we must pay more attention to the fact that the three lines of the electronic ruler cannot be connected wrongly. The power lines and output lines cannot be exchanged. If the above line is connected wrongly, there will be a large linear error, it is difficult to control, the control accuracy will become very poor, and the display is prone to beating and so on.
