Troubleshooting of ultrasonic liquid level sensor
Ultrasonic level meter in the use of possible problems, we can take the following measures:
1. In order to prevent the ultrasonic level gauge signal line from being interfered by strong voltage, large current and strong electromagnetic on the power line. The signal line is routed separately, away from the power line and the lighting line, and routed separately. Once encountered such a fault phenomenon, once the fluorescent lamp of the duty room is turned on, the second table of the liquid level meter has no data display. The instrument and the fluorescent lamp are not controlled by the same control power supply, after analysis, the reason is that the fluorescent lamp power line is too close to the liquid level meter transmitter, the ballast generates high voltage when the fluorescent lamp starts, the energized wire produces a strong electromagnetic field, and the ultrasonic level signal of 4-20mA is interfered with. After the fluorescent lamp power cord is far away from the liquid level meter, the fault phenomenon disappears.
2. Do a good signal shielding layer to prevent signal interference
Have tried, the signal line shielding wiring is correct, only use the hand to shake the signal line, the instrument display data will jump. In order to better play a shielding effect, we wear conductive steel pipes outside the signal line. In addition, the signal line end in the secondary table and the shielded terminal are obviously separated, and the burr of a small point of the shield layer and the signal line seem to stick will affect the stability of the signal. The same signal loop and the same shield layer use a single point ground, only one ground point, to avoid the potential difference existing in the ground loop will interfere with the instrument.
3. In order to prevent poor contact of the signal cable, try not to leave a connector in the middle of the signal cable, and do not loose the terminal crimping, otherwise the contact resistance will be relatively large. The signal line joint must be welded with a soldering iron to reduce the potential trouble.
4. In order to avoid moisture in the signal line of the ultrasonic level gauge, the signal line should be placed on the support when walking the cable. The signal line is soaked in water, especially at the junction, which will cause the disturbance of the instrument signal.
5. Adjust the transducer in the ultrasonic tube, the surface is perpendicular to the measured liquid level, and the levelness is controlled at 2°.
6. Adjust the distance between the ultrasonic probe and the liquid surface. Too far, the signal received by the probe is too weak to be distinguished from the noise signal; Too close, into the probe’s blind area, can not be distinguished.
