I.The instrument shows nothing.
(1)Power supply not connected/abnormal voltage;
(2)Loose wiring, broken wires, or blown fuses;
(3)The converter circuit board is damp or damaged; failure of the instrument power module.
(4) Instrument power module failure.
Troubleshooting Methods
(1)Check the power supply line to confirm that the voltage meets the rated requirements of the instrument and is stable;
(2)Check and fasten the terminal blocks, inspect the continuity of the line, and replace the blown fuse;
(3)Power off and restart. If the abnormality persists, check the circuit board. If necessary, return it to the factory or replace the converter;
(4)Detect the output of the power module and replace it if it is abnormal.
II.There is medium flow, but the displayed value is zero or remains unchanged for a long time.
(1) The actual flow rate is lower than the lower limit of the instrument;
(2) Cable failure;
(3) Probe blockage or scaling;
(4) The vortex generator is entangled and stuck;
(5) The installation direction is opposite to the flow direction;
(6) Damage to sensor components.
Troubleshooting Methods
(1)Ensure that the flow rate is within the range of the instrument.If it is below the lower limit, replace the instrument with a smaller range or adjust the flow rate;
(2)Inspect the cable between the sensor and the converter, repair open circuits and short circuits, and ensure reliable wiring;
(3)After powering off and relieving pressure, disassemble the probe, clean the detection surface with a soft brush and clean water, and remove debris from the vortex generator;
(4)Confirm the medium flow direction to ensure that the instrument arrow is consistent with the flow direction;
(5)Have professionals inspect the piezoelectric element, and replace the sensor if it is damaged.
III.The indicated value is too high/too low, with a large deviation from the actual flow rate
Indicated value is too high
(1)The meter factor(K factor)is set too large
(2)The medium temperature and pressure do not match the calibration conditions, and temperature and pressure compensation is not enabled
(3)The inner wall of the measuring tube is scaled, reducing the effective flow area
(4)The medium contains bubbles, causing misjudgment of the vortex frequency
(5)Pipeline leakage, with external medium mixing in and interfering with the measurement
Indicated value is too low
(1)The meter factor (K factor) is set too small
(2)The probe is worn or contaminated, resulting in weakened signal strength
(3)The upstream and downstream valves are not fully open, causing throttling and disturbance effects
(4)Pipeline leakage, resulting in a reduction in the actual flow rate of the measured medium
(5)The medium viscosity is too high, inhibiting the normal formation of vortices
IV.Zero drift (when the flow rate is zero, the indicated value is not zero)
(1)Residual medium disturbance exists in the pipeline, forming a false flow signal
(2)The converter zero point is not calibrated, or the calibration method and timing are improper
(3)The insulation performance of the probe decreases, and the signal noise increases
(4)Changes in ambient temperature lead to shifts in sensor characteristics
(5)On-site electromagnetic interference affects zero stability
Troubleshooting Methods
(1)Close the upstream and downstream valves, empty the medium in the pipeline, perform zero calibration according to the instrument manual, and complete the empty pipe zeroing operation.
(2)Test the insulation resistance of the probe; if it does not meet the standard, replace the probe.
(3)Add heat insulation layers to prevent drastic changes in ambient temperature from affecting sensor performance.
(4)Check the instrument grounding condition to ensure that the grounding resistance is less than 4Ω and reduce electromagnetic interference.
(5)Calibrate the instrument zero point regularly; newly installed instruments must undergo zero calibration. For steam working conditions, the instrument should be started only after the condensed water has stabilized.
V.The output signal fluctuates violently and irregularly
(1)Excessive pipeline vibration exceeds the standard, interfering with the acquisition and transmission of vortex street signals;
(2)The medium contains gas-liquid two-phase flow or pulsating flow, resulting in irregular vortex formation and disordered signals;
(3)Improper setting of instrument filtering parameters, which cannot effectively filter interference and affects data stability;
(4)Decreased sensitivity of the probe, weakening the ability to identify and capture signals;
(5)Unstable fluid flow rate (fluctuations in valve opening, abnormal pump operation), leading to fluctuations in vortex frequency;
(6)Electromagnetic interference (from high-voltage equipment such as frequency converters and large motors), affecting signal transmission and zero-point stability.
Troubleshooting Methods
(1)Use a vibration meter to detect the vibration of the shell. If it exceeds the standard, add or subtract shock absorption devices, reinforce the pipeline, keep away from the vibration source, and enable vibration filtering;
(2)Install a gas-liquid separator and a buffer tank to eliminate the interference of two-phase flow and pulsating flow;
(3)Enable the band-stop filter on the converter to shield the characteristic frequency of the equipment and adjust the damping time;
(4)Check the piezoelectric element of the probe, and replace it if its sensitivity is insufficient;
(5)Check the upstream valve and pump to stabilize the fluid flow rate;
(6)Thread the signal wire through a metal pipe for shielding, keep it away from power cables, add an isolation transformer to the power supply, and ensure good grounding.
VI.Weak or no signal output (no alarm prompt)
(1)The actual flow exceeds the instrument range;
(2)Probe failure, abnormal signal output;
(3)Poor wiring contact;
(4)Severe electromagnetic interference;
(5)Incorrect instrument parameter settings (such as improper range and unit settings).
Troubleshooting Methods
(1) Regularly disassemble and clean the probe. Choose probes made of anti-adhesion materials (such as ceramics). Replace the probe directly if it is damaged.
(2) Check the terminal blocks and re-tighten the connections; check whether the cable shielding layer is grounded properly; directly replace damaged or aged cables.
(3) Ensure that the upstream straight pipe section is ≥10D and the downstream straight pipe section is ≥5D in accordance with the manufacturer"s requirements; install a rectifier to improve the flow pattern when space is insufficient.
(4) Verify the process flow to ensure it is within the instrument range; adjust the process flow or replace the instrument with an appropriate range when it exceeds the range.
(5) Use an oscilloscope to detect the original waveform of the probe. If there is no stable sine wave, contact professional personnel to repair the internal circuit of the sensor.
VII.The instrument alarms frequently (over-range, weak signal, etc.)
(1)The actual flow exceeds the instrument range
(2)Probe failure, abnormal signal output
(3)Poor wiring contact
(4)Severe electromagnetic interference
(5)Incorrect instrument parameter settings (range, unit, etc.)
Troubleshooting Methods
(1)Verify the process operation status, replace the flow meter with an appropriate range, or adjust the instrument range parameters.
(2)Detect the output signal of the probe, and replace the probe if the signal is abnormal.
(3)Re-tighten the terminal blocks to ensure reliable single-ended grounding of the shielding layer.
(4)Lay the signal cable in a metal pipe, keep it away from power cables, optimize the grounding system, and ensure that the grounding resistance is ≤10Ω.
(5)Check the instrument parameters to ensure that the range and display unit are consistent with the process requirements, and correct incorrect settings.
VIII.Environmental factors causing abnormal operation of the instrument
(1)Electromagnetic interference (frequency converters, large motors, etc.);
(2)Ambient temperature beyond the range (lower than -40℃ or higher than +85℃);
(3)Excessive ambient humidity, leading to moisture inside the instrument.
Troubleshooting Methods
(1)Optimize the wiring, lay signal wires and power cables separately with a spacing of not less than 30 cm, shield the signal wires with metal pipes, and ensure reliable independent grounding of the instruments.
(2)Add thermal insulation layers, replace high and low temperature resistant probes, and ensure that the ambient temperature is within the allowable operating range of the instruments.
(3)Strengthen the protection of the instruments, avoid using them in humid environments, dry the damp instruments, and replace internal components if necessary.
IX.Abnormal measurement caused by improper installation
(1)Insufficient length of the straight pipe section leads to turbulent medium flow, affecting measurement stability;
(2)Incorrect installation direction, such as when installed vertically, the medium does not flow from bottom to top;
(3)The flowmeter is not concentric with the pipeline, resulting in installation stress and measurement deviation;
(4)The installation position is close to resistance components such as elbows, valves, and pumps, and is in a turbulent flow area.
Troubleshooting methods:
(1)Re-select the location for installation, ensuring 10D straight pipe sections upstream and 5D straight pipe sections downstream, away from turbulent flow interference areas such as elbows, valves, and pumps; install a flow straightener when space is limited.
(2)Install strictly in accordance with the instructions: when installing horizontally, the sensor axis should be parallel to the ground; when installing vertically, the medium should flow from bottom to top, and vertical downward installation is prohibited for liquid media.
(3)Adjust the concentricity between the flowmeter and the pipeline to eliminate installation stress.
(4)Select the installation location reasonably, avoiding areas with unstable flow patterns such as pump outlets and valve downstream.
Systematic Troubleshooting Process
1.Initial Inspection: Confirm that the power supply, wiring, and grounding are normal, and observe whether the instantaneous flow curve fluctuates.
2.Process Verification: Ensure that the medium flow is within the range, the pipeline is full, and the medium is free of bubbles, impurities, and abnormal viscosity.
3.Parameter Validation: Check parameters such as instrument range and K coefficient to ensure they are consistent with the actual working conditions, and correct any incorrectly modified parameters.
4.Signal Diagnosis: Use an oscilloscope to detect the probe waveform, compare the signals of the probe and the secondary instrument, and confirm that the transmission is normal.
5.Offline Testing: Remove the instrument for calibration and simulated working condition tests to check for faults in the main body.
6.Professional Troubleshooting: Use split testing to locate the faulty module; if the problem cannot be resolved, contact the manufacturer or return the instrument to the factory for repair.
