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1. Common causes of electromagnetic flowmeter reading 0
The common causes of electromagnetic flowmeter reading 0 can be divided into four categories: abnormal sensing and detection, abnormal fluid working conditions, electrical signal link faults, and parameter configuration errors. The specific fault points are as follows:
1. Fault in sensing and monitoring components.
The measuring electrode is covered or corroded: suspended solids or scaling layers in the measured medium wrap around the electrode, or strongly corrosive media corrode the electrode, blocking the collection of potential difference between the electrode and the collision body in the flow; Insulation impurities (such as oil stains and paint) adhering to the electrode surface can also cause signal transmission failure. 2. Excitation circuit failure: The excitation coil is burned out, the wiring is loose, or the excitation power supply is abnormal, which cannot generate a stable alternating magnetic field and cannot sense the potential signal corresponding to the fluid flow rate. 3. Poor grounding: The grounding electrode of the flowmeter fails, and the grounding resistance exceeds the standard (industry standard requirement ≤ 10 Ω), which cannot establish a stable signal reference potential, resulting in abnormal signal acquisition. 4. Sensor housing damage: The housing cracks, causing the medium to penetrate the internal circuit, or the housing deforms and squeezes the measuring tube, obstructing fluid flow and damaging the internal signal transmission environment.2. Abnormal fluid working conditions 1 No fluid flow in the pipeline: The upstream valve is completely closed, the pump unit is stopped, or the pipeline is blocked, a
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2. Low fluid conductivity: Electromagnetic flow meters require the conductivity of the measured medium to be ≥ 5 μ S/cm (higher requirements for high-precision models), and ultrapure water, insulating oil and other media cannot form a conductive circuit, unable to generate induced signals
When the sensing signal strength is below the lower limit of the instrument detection, it will be displayed as 0.
III. Electrical and Signal Link Malfunctions 1 Power supply abnormality: Instrument power supply interruption, power supply voltage exceeding the rated range (such as 220VAC power supply deviation exceeding ± 10%), causing the instrument to fail to start up and operate normally
2. Signal transmission abnormality: Loose, short circuited or open circuited indirect wires between the transmitter and the converter, or strong electromagnetic interference generated by nearby high-power equipment (frequency converter, motor) shielding weak induction signals, resulting in signal transmission failure
3. Internal fault of the converter: signal amplification module and A/D conversion module are damaged, unable to convert the collected weak potential signal positive sum signal into a displayed current reading.
.Fourth, Parameter Configuration Error 1 Flow range configuration error: Setting the upper limit of the range much higher than the actual flow rate, resulting in the signal corresponding to the actual flow rate being judged as a minimum value close to 0
2. Output mode or unit configuration error: The instrument output mode is switched to non display mode, or the unit setting is incorrect, resultin
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