Inspection steps for zero point instability of electromagnetic flowmeter

Check procedure for zero-point instability of electromagnetic flowmeter:

1. It is common to encounter cases where the valve is not fully sealed due to long-term use or dirty liquid, especially for large valves. Another common reason is that the flow meter has several branch pipes in addition to the main pipe, and the valves of these branch pipes are forgotten or ignored.

2. The liquid conductivity changes or is uneven, which will cause the zero point to change when it is stationary, and the output will shake when it is active. Therefore, the location of the flow meter should be far away from the injection point or the downstream of the chemical reaction section of the pipeline. It is better to install the flow sensor upstream of these places.

3. Since the scale on the inner wall surface and the degree of electrode contamination cannot be completely consistent and symmetrical, the equilibrium state of the initial zero setting is destroyed. The solution is to remove dirt and accumulated scale; if the zero position does not change much, you can also try to reset it to zero.

4. Changes in the status of the power equipment close to the flow sensor (such as an increase in leakage current) cause changes in ground potential, which will also cause changes in the zero point of the electromagnetic flowmeter. Sometimes the environmental conditions are good and the electromagnetic flowmeter can work normally without grounding. However, once the good environment does not exist, instrument problems will occur.

5. Check the flow chart. Reduced insulation of the signal loop will cause zero point instability. The main reason for the insulation degradation of the signal loop is the insulation degradation of the electrode parts. The wire connections are not tightly sealed, and moisture, acid mist or dust particles invade the instrument junction box or cable protective layer, causing the insulation to degrade.

If the problem still cannot be solved, you can contact the technical engineers of Supmea Automation Technology Co., Ltd. for technical guidance.