Maintenance example: troubleshooting and maintenance of radar level meter F140

1. Instrument type: 26G high frequency radar level meter

2. Failure category: F140

3. Failure analysis: F140 means that the echo signal is weak or there is no echo signal.

So, how to solve this problem? The specific operations are as follows:

Step 1:Troubleshooting on site

a. Check that the range set by the radar must be greater than the total range of the tank.

b. When the measured medium is liquid, check whether the radar sensor enters water vapor.

When the measured medium is solid, it needs to be checked for crystallization or excessive dust accumulation.

The above cleaning is complete and reinstalled, and then adjust the radar angle until the radar echo signal is the strongest.

Step 2: Oscilloscope test and repair

Oscilloscope test no output waveform

1. Firstly, visually check the situation of no missing or missing welding;

2. Use an oscilloscope to check that L1 has no VHD signal input in the middle of the week(Normal see Figure 1)

3. Then check that the input pin 4 of the VHD signal output chip U3 has no input (see Figure 2 for normal), check the 4 pin circuit of U3, and find that D9 is open. When replacing it, it is found that D9 is broken. After replacement, the distance measurement is normal.

Any new inquiry about radar level gauge, please feel free to contact us!