Electromagnetic flowmeter common failure

Common faults of electromagnetic flowmeters

There are two common faults of electromagnetic flowmeters during operation: one is the fault of the instrument itself, that is, the structural parts of the instrument or Failures caused by damaged components; second, failures caused by external causes, such as improper installation, flow changes, deposition and scaling, etc. We discuss these two types of failures.

The instrument has no flow signal output

1. Cause analysis: This type of failure is common during use

The reasons generally include:

(1) The power supply of the instrument is abnormal;

(2) The cable connection is abnormal;

(3) The liquid flow condition does not meet the installation requirements;

(4) The sensor components are damaged or there is an adhesion layer on the inner wall of the measurement;

(5) The converter components are damaged.

2. Solution:

(1) Confirm that the power supply is connected, check whether the output voltage of each channel of the power circuit board is normal, or try to replace the entire power circuit board to determine whether it is good. bad.

(2) Check whether the cable is intact and the connection is correct.

(3) Check the direction of liquid flow and whether the liquid in the tube is full. For electromagnetic flowmeters that can measure forward and reverse, if the directions are inconsistent, they can be measured, but the set display flow direction does not match the forward and reverse directions and must be corrected. If the workload of dismantling the sensor is heavy, you can also change the direction of the arrow on the sensor and reset the displayed instrument symbol. The pipe is not full of liquid, which is mainly caused by the improper installation position of the sensor. Measures should be taken during installation to avoid causing the liquid in the pipe to be full of liquid.

(4) Check whether the inner wall electrode of the transmitter is covered with a liquid scaling layer. Measurement liquids that are prone to scaling must be cleaned regularly.

(5) If it is determined that the fault is caused by damage to the converter components, just replace the damaged components.

2. Output value fluctuation

Cause analysis: Most of these failures are caused by the influence of the measurement medium or the external environment. To ensure measurement accuracy, such failures cannot be ignored. In some production environments, due to the large vibration of the measuring pipe or liquid, the circuit board of the flow meter may become loose, which may also cause fluctuations in the output value.

Solution:

(1) Confirm whether it is due to process operation, and the fluid does flow. At this time, the flow meter only reflects the flow condition truthfully, and the fault can be eliminated by itself after the pulsation ends. .

(2) Electromagnetic interference caused by external stray currents, etc. Check whether there are any large electrical appliances or welding machines operating in the operating environment of the instrument. Make sure the instrument is well grounded and the operating environment is good.

(3) When the pipeline is not filled with liquid or the liquid contains bubbles, both are caused by process reasons. At this time, you can ask the process personnel to confirm that the output value can return to normal after the liquid tube is full or the bubbles subside.

The transmitter circuit board is a plug-in structure. Due to the large vibration of the on-site measurement pipe or liquid, flow will often occur.The meter's power board is loose. If it is loose, disassemble the flow meter and re-fix the circuit board.