E + H electromagnetic flowmeter no flow signal output fault repair

Case introduction

　　E + H electromagnetic flowmeter operation failure there are two kinds. One is caused by damage to the structure or components of the instrument. The other is a failure due to external causes, such as improper installation, motion deformation, deposition and scaling. Both types of failures will be discussed in this article.

　　eh electromagnetic flowmeter fault repair

　　First, E + H electromagnetic flowmeter no flow signal output

　　I. Cause analysis

　　This kind of failure is more common in the use of the process, the reasons are generally the following:

　　(1) power electromagnetic flowmeter is not normal.

　　(2) Cable connection is abnormal.

　　(3) Liquid activity conditions do not meet the installation requirements.

　　(4) Electromagnetic flowmeter sensor element damage or flowmeter wall attached to a layer.

　　(5) Damage to the converter components.

　　2. Solution

　　Need to confirm that the power supply has been turned on, check whether the output voltage of the power supply circuit board is normal. You can replace the whole power supply circuit board to check whether it is good or bad.

　　Need to check whether the cable is intact and connected correctly.

　　Need to check the direction of liquid flow and whether the tube is full of liquid. For forward and reverse measurement of electromagnetic flowmeter, if the direction is not the same, it can also be measured. However, if the direction of the set display flow is not consistent, it should be corrected. If the workload of dismantling the sensor is large, you can also change the direction of the arrow on the sensor and reset the display meter symbol. The lack of liquid in the pipeline is mainly caused by the improper installation position of the sensor. Therefore, electromagnetic flow measurement should be carried out at the time of installation so as not to cause a lack of liquid in the pipeline.

　　It is necessary to check whether the electromagnetic flowmeter electrode on the inner wall of the transmitter is covered with a liquid scarification layer. Electromagnetic flow measurement for easily shocked liquids should be cleaned periodically.

　　If the failure is caused by its damage, the transducer assembly should be replaced.

　　Ⅱ. Electromagnetic flowmeter output value fluctuations

　　I. Cause analysis

　　This type of failure is caused by the electromagnetic flow measurement medium or the influence of the external environment, to rule out external interference can be eliminated by itself. Such failures should not be ignored to ensure the accuracy of the measurement. In some production environments, the electromagnetic flowmeter measurement pipeline or the increase in liquid will lead to the electromagnetic flowmeter circuit board loose, will also cause fluctuations in the output value.

　　2. Solution

　　Need to confirm whether the cause is process manipulation. When the fluid pulsation occurs, the electromagnetic flowmeter only truthfully reflect the activity state, pulsation after the fault can be eliminated by itself.

　　External stray current can cause electromagnetic interference. It is necessary to check that large electrical appliances or welders are not operating in the instrument's operating environment. In addition, it must be ensured that the instrument is earthed and operates in a good environment, e.g. if the flowmeter alarm is functioning well.

　　When the pipeline of the electromagnetic flowmeter is not filled with liquid or there are bubbles in the liquid, both are caused by technical reasons. At this time, you should ask the process personnel to confirm that the output value can be returned to normal after the liquid is full or the bubble is flattened.

　　The transmitter circuit board is plug-in structure. The power board of the flowmeter is often loosened due to the increase of measuring pipes or liquids. If this happens, the electromagnetic flowmeter can be removed and the circuit board can be fixed again.