Electromagnetic Flowmeter Fault Analysis & Troubleshooting

1. No Flow Signal / Zero Reading (No Output)

• Possible Causes
  1. The measuring pipe is not fully filled with medium.
  2. Power supply failure or loose wiring terminals.
  3. Broken excitation coil or damaged electrode.
  4. Flow rate is lower than the instrument’s minimum measurable range.
  5. Blockage inside the sensor pipe.
• Solutions
  1. Adjust pipeline layout to ensure full pipe flow.
  2. Check power circuit and re-tighten all connections.
  3. Test coil and electrode resistance, replace damaged parts.
  4. Select a flowmeter with a smaller measuring range.
  5. Clean foreign matters inside the sensor.

2. Unstable Fluctuating Reading

• Possible Causes
  1. Medium contains air bubbles or solid impurities.
  2. Severe pipeline vibration or external electromagnetic interference.
  3. Poor grounding or damaged shielding wire.
  4. Partial adhesion of dirt on electrodes.
  5. Abnormal liquid conductivity.
• Solutions
  1. Install exhaust valves to remove gas; filter impurities.
  2. Reinforce pipeline fixation; stay away from high-power electrical equipment.
  3. Reconnect grounding wire and inspect shielding layer.
  4. Clean electrode surface regularly.
  5. Confirm the medium meets conductivity requirements.

3. Large Measurement Deviation (Inaccurate Value)

• Possible Causes
  1. Incorrect parameter setting (range, pipe diameter, unit).
  2. Wrong installation direction of the sensor.
  3. Serious scaling on the inner wall of the measuring tube.
  4. Inconsistent actual medium with calibrated medium.
  5. Excessive upstream/downstream straight pipe section deficiency.
• Solutions
  1. Recheck and reset all configuration parameters.
  2. Install the sensor strictly according to the flow direction mark.
  3. Remove scaling and clean the measuring tube.
  4. Recalibrate if the medium changes greatly.
  5. Ensure sufficient straight pipe sections before and after installation.

4. Cannot Return to Zero (Zero Drift)

• Possible Causes
  1. Residual medium or sediment inside the pipe.
  2. Electrode corrosion or surface contamination.
  3. Long-term operation without zero calibration.
  4. Uneven internal stress of the pipeline.
• Solutions
  1. Empty the pipeline completely before zero setting.
  2. Polish and clean corroded or dirty electrodes.
  3. Perform regular zero point calibration.
  4. Eliminate pipeline stress and re-fix the sensor.

5. Alarm Code Triggered

• Common Alarms & Handling
  1. Excitation Fault: Check excitation circuit, coil and wiring.
  2. Electrode Open Circuit: Inspect electrode cable and electrode integrity.
  3. Over Range: Confirm actual flow exceeds measuring range, replace matched model.
  4. Communication Fault: Check communication line, address and protocol settings.

6. Signal Loss under Normal Flow

• Possible Causes
  1. Cable aging, breakage or water ingress.
  2. Loose contact between sensor and converter.
  3. Ambient temperature exceeds the instrument’s operating limit.
• Solutions
  1. Replace damaged signal cables and do waterproof treatment.
  2. Reconnect and lock the connector.
  3. Improve on-site heat dissipation or select high-temperature resistant model.

Supplementary Notes

1. Cut off power supply before all maintenance operations to avoid electric shock.
2. Regular cleaning and inspection can effectively reduce failure rates.
3. If internal components are severely damaged, please contact professional after-sales service.