1. Signal-related faults
1. Low signal strength or insufficient Q value
Reasons: Improper installation position of the probe, insufficient coupling agent, scaling on the inner wall of the pipeline, or presence of bubbles
Solution:
Re-grind the pipeline to a Ra3.2μm finish, and evenly apply a special silicone grease coupling agent
Adjust the probe to the 3/9 o’clock position of the pipeline, ensuring horizontal alignment
For large pipe diameters (DN>300mm), it is recommended to switch to the Z-shaped installation method
Check and ensure full pipe flow, and install an exhaust valve to eliminate air bubbles
2. Severe signal fluctuation
Reason: pipeline vibration, electromagnetic interference, or fluid containing solid particles
Solution:
Reinforce the pipeline support and keep it away from vibration sources such as pumps/valves (recommended distance ≥5D)
Use shielded twisted-pair cables, with signal lines and power lines laid separately
For fluids containing particles, select Doppler probes or install them in vertical pipelines
II. Measurement accuracy issues
1. Large reading deviation
Reason: Parameter setting error, influence of pipeline lining, or temperature change not compensated
Solution:
Re-enter accurate pipe diameter and wall thickness data (cast iron pipes require special calibration)
Select the “Penetration Lining” measurement mode for the lined pipeline
For high-temperature media (>80℃), it is necessary to select high-temperature resistant models and enable temperature compensation
2. Air traffic control has flow display
Reason: Circuit fault or strong electromagnetic interference
Solution:
Check the stability of the power supply (voltage fluctuation should be <±10%)
Enable the air traffic control detection function and set the zero flow threshold
Install a magnetic ring filter on the 485 communication line
III. Hardware failures
1. Probe short circuit/open circuit
Detection method:
After powering off, use a multimeter to measure the probe resistance (normal value: 340-350Ω)
Compare the resistance differences between upstream and downstream probes (deviation >5% indicates abnormality)
Treatment measures:
Replace the damaged probe cable (with waterproof treatment of the connector)
It is recommended to replace the entire probe if it has aged (used for >5 years)
2. The host computer has no display
Troubleshooting steps:
Check whether the fuse is blown
Verify power supply properties (AC220V/DC24V)
Measure the voltage of the power supply terminal on the motherboard
IV. Preventive maintenance suggestions
Regular maintenance:
Check the condition of the coupling agent every 3 months
Conduct on-site calibration with standard flow devices every year
Environmental management:
Avoid prolonged exposure to an environment with humidity >85%
Intrinsically safe products are required in explosion-proof areas
Spare parts strategy:
It is recommended to replace the probe compulsorily every 5 years
Always keep consumables such as coupling agents and sealing rings on hand
For complex malfunctions (such as damaged circuit boards), it is recommended to contact the manufacturer for professional repairs. Some brands, such as Hebei Haifeng, offer remote diagnostic services. Daily operations should strictly follow the installation specifications in the product manual, which can reduce the occurrence of over 80% of malfunctions.
