How to deal with electromagnetic interference of ultrasonic level sensor

 

Step 1: ground the ultrasonic level gauge.       

There are three terminals on the ultrasonic liquid level meter, one of ultrasonic level measurement transducer is specially grounded. After field grounding, the echo pattern becomes as follows.

From the figure, the interference has been reduced a lot, which shows that in the field of electromagnetic interference, grounding is a conventional method to reduce interference. In general, after grounding, it can be measured correctly. However, after the field is grounded, it can not be measured correctly. So it can only be isolated. A signal isolator is added between the on-site frequency converter and the ultrasonic liquid level meter. The signal isolator of ultrasonic level transducer blocks the interference of the frequency converter. The echo menu at this time is as follows:      

At this time, the echo menu is very clear, without any trace of electromagnetic interference. Comparing with the actual liquid level, the ultrasonic level measurement sensor is measured by ultrasonic liquid level meter is correct. Through this example, we know that in case of strong electromagnetic interference sources such as frequency converter, motor, high-voltage wire, etc., we need to do the following steps: First, entering the echo menu (press and hold the up key first, and then press and hold the set key for three seconds, the echo menu will appear. )    

1.Connect the grounding terminal of ultrasonic liquid level meter to the real ground separately, and do not share the same ground with other equipment.