The unstable zeroing of Low price magnetic flow meter supplier china is often encountered in industrial production. It is analyzed that there are many reasons for this problem, mainly including the following factors:
1. The pipeline is not filled with liquid or the liquid contains bubbles. Objectively, it is assumed that there is no activity in the flow sensor, but in practice, there is a small amount of activity.

2. If the valve is used for a long time or the liquid is dirty, the incomplete sealing of the valve will also lead to zero point instability.

3. If the liquid conductivity changes or is uneven, the zero point will change when it is stationary, and the output will shake when it is active.

4. Because the fouling on the inner wall and the electrode can not be completely the same and symmetrical, the equilibrium of the initial zero setting is destroyed.

5. The change of the state of the power equipment near the flow sensor (such as the increase of leakage current) constitutes the change of the grounding potential, which will also cause the change of the zero point of the intelligent electromagnetic flowmeter.

Through the analysis of the problem, we can find the corresponding solutions according to the corresponding phenomena.

I. first rule out inspection: inspection procedure

Check the flow of unstable zero point of Low price magnetic flow meter supplier china First, make preliminary investigation and judgment according to the overall consideration of the process, and then carefully check and try to eliminate the faults one by one The sequence of inspection items listed in the process is as follows:

(1) Through observation or inquiry, it can be understood that those without major operations are in the first place, that is, easy first and difficult later;

(2) According to the past on-site maintenance experience, the one with high frequency and high probability in the future is the first;

(3) Check the sequence requirements required by itself If the causes of the following faults are confirmed through preliminary investigation, detailed inspection can also be carried out in advance

2、 The Low price magnetic flow meter supplier china sensor is imperfect according to the ground and is subject to external interference such as stray current:

External interference such as pipeline stray current affects the good grounding protection of main Low price magnetic flow meter supplier china. Generally, the grounding resistance is required to be less than 1000. Do not share the grounding with other motors and electrical appliances Sometimes the environmental conditions are good, and the intelligent Low price magnetic flow meter supplier china can work normally without grounding. However, once the good environment does not exist, the instrument will fail. It will be troublesome to check again at that time

The change of the state of the power equipment near the flow sensor (such as the increase of leakage current) forms a change according to the ground potential, which will cause the zero point change of the intelligent Low price magnetic flow meter supplier china

3、 Causes of Low price magnetic flow meter liquid (such as liquid conductivity uniformity, electrode pollution, etc.);

When the liquid conductivity changes or is uneven, the zero point will change at rest, and the output will shake when flowing Therefore, the Low price magnetic flow meter supplier china shall be far away from the injection point or the downstream of the chemical reaction section of the pipeline, and the flow sensor shall preferably be installed at the upstream of these places

If the liquid contains solid phase, or impurities deposit on the inner wall of the measuring tube, or scales on the inner wall of the measuring tube, or the electrode is polluted by grease, etc., the zero point may change Because the scale on the inner wall surface and the pollution degree of the electrode can not be exactly the same and symmetrical, which destroys the balance set by the initial withering of the plant Active measures shall be taken to remove the dirt and sediment; If the zero partner changes little, you can also try to reset it.

4、 The insulation of signal circuit of Low price magnetic flow meter supplier china decreases

The signal circuit insulation drops, which will cause zero point instability The signal circuit insulation drop is mainly caused by the drop of insulation at the wrapped pole. However, it cannot be ruled out that the signal cable and its connecting terminal insulation drop or damage Sometimes, the site environment is very harsh. If the instrument cover / wire connection is inadvertently sealed, the moisture, acid mist or powder dust will invade the instrument junction box or cable protective layer, resulting in insulation degradation The insulation resistance of the signal circuit shall be checked separately at the cable side and the flow sensor side, and tested with a megger Because the signal cable is easy, it can be made first The flow sensor is divided into two times: measuring the contact resistance on the surface of the electrode filled with liquid and measuring the insulation resistance of the U electrode after a tube
5、 Check the electrode contact resistance and electrode insulation resistance in 2 steps
(1) The liquid contact resistance flow sensor filled with liquid measuring electrode surface scoop shall remove the signal cable wiring, and use a multimeter to measure the resistance between each electrode and the grounding point respectively. The left of the two electrodes to the ground shall be 10% - 20% Section 9 "measurement of one / electrode contact resistance" will further explain
(2) Empty pipe measuring electrode insulates the empty measuring pipe, wipe the inner surface with a dry cloth, and after it is completely dry, measure the resistance between each electrode and the ground with a h500vdc megger. The resistance must be more than 100m Ω