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1. The vortex flowmeter is powered on, the valve is not open, and there is a signal output. Solution: ①The output signal of the sensor (or detection element) is poorly shielded or grounded, causing external electromagnetic interference. ； ②The instrument is too close to strong electrical equipment or high-frequency equipment, causing space electromagnetic radiation interference and affecting the instrument. ； ③There is strong vibration in the installation pipeline ； ④The sensitivity of the converter is too high and it is too sensitive to interference signals. ； Measures that should be taken are to strengthen shielding and grounding, eliminate pipeline vibration, and adjust and reduce the sensitivity of the converter. 2. For a vortex flowmeter that is in intermittent operation, the power supply is not cut off, the valve is closed, and the output signal does not return to zero. ； The main reasons may be the impact of pipeline oscillation and external electromagnetic interference. Solution: The sensitivity of the converter should be lowered and the trigger level of the shaping circuit should be increased to suppress noise and overcome false triggering during intermittent periods. 3. In the power-on state, if the downstream valve is turned off, the output will not return to zero. If the upstream valve is closed, the output will return to zero. This is mainly due to the influence of the pulsating pressure of the fluid upstream of the Fujie flowmeter. If the vortex flowmeter is installed on a T-shaped branch pipe and there is pressure pulsation in the upstream main pipe, or there is a pulsating power source (such as a piston pump or Roots blower) upstream of the vortex flowmeter, the pulsating pressure will cause false signals in the vortex flowmeter. Solution: Install the downstream valve upstream of the vortex flowmeter, and close the upstream valve during shutdown to isolate the influence of pulsating pressure. However, when installing, the upstream valve should be as far away from the vortex flowmeter as possible, and sufficient straight pipe length should be ensured. 4. In the power-on state, the output of the upstream valve does not return to zero when the upstream valve is closed. Only the output of the downstream valve returns to zero. This failure is caused by fluid disturbance in the pipe, and the disturbance comes from the pipeline downstream of the vortex flow meter. In the pipeline network, if the downstream straight pipe section of the vortex flowmeter is short and the outlet is close to the valves of other pipelines in the pipeline network, the fluid disturbance in these pipelines (such as the opening and closing of valves in other downstream pipelines, frequent movements of regulating valves) will be transmitted to the vortex flowmeter detection element, causing false signals. Solution: Lengthen the downstream straight pipe section to reduce the impact of fluid disturbance. 5. After powering on and flowing, the output (or indication) signal of the vortex flowmeter does not change with the flow rate. Due to poor grounding of the shielding layer of the signal line or improper selection of the grounding point, external electromagnetic interference is very serious (such as 50Hz power frequency interference), which completely suppresses the weak vortex signal, and the output signal is completely submerged by noise interference. At this time, adjusting the valve opening and the gain of the instrument will not help. The connection between the detection element and the converter is disconnected, the input end of the preamplifier is open circuit, or a signal line of the detection element is short-circuited to the ground, causing the input of the preamplifier to be seriously unbalanced. Common mode interference takes advantage of the opportunity, the vortex signal is suppressed by noise interference, and the output end is completely controlled by interference. The gain of the preamplifier is too high, causing self-oscillation, and the output is locked at the self-oscillation frequency. Solution: The above faults are caused by electrical reasons. Only by strengthening shielding and grounding, routing wiring properly, and reducing or eliminating interference can the normal operation of the instrument be restored. 6. Strong vibration of the pipeline (or environment). When the vibration direction is consistent with the sensitive direction of the instrument detection component, the vibration completely suppresses the vortex signal, and the output signal is the vibration frequency signal. Adjusting the valve opening cannot change the output. Solution: Use vibration reduction measures (add a pipe anti-vibration seat, fix the pipe), clarify the vibration direction, rotate the sensor of the vortex flowmeter around the pipe axis ±90°C, and adjust the sensitive direction of the detection element to be perpendicular to the vibration direction, which can reduce the impact of vibration or appropriately reduce the gain and trigger sensitivity of the preamplifier. Taking the above measures can eliminate the effects of vibration. 7. The "locking" of the pulsating flow on the vortex signal. In the absence of effective suppression of the influence of the pulsating flow, the destructive effect of the pulsating flow on the stable separation of the vortex cannot be underestimated. If the pulsating frequency matches the frequency of the vortex signal, the vortex signal may be "locked" near that frequency. At this time, the output signal frequency will not change if the sensitivity of the valve and instrument is adjusted. Solution: Take measures to absorb or reduce fluid pulsation during the design and construction of instrument installation pipelines. 8. The instrument exceeds the calibration period and the instrument coefficient K changes. ； The set parameters (such as measuring tube inner diameter, standard state density and instrument coefficient) are incorrect ； The zero point drift of the analog conversion circuit or the range adjustment is incorrect. ； The power supply deviates too much from the rated value or the ripple is too large. Solution: Send the instrument for inspection quickly, check various set parameters in a timely manner, and regularly calibrate the zero point and range of the instrument to maintain the integrity of the instrument. 9. The vortex flowmeter transmitter makes an abnormal whistling sound.: (1) The flow rate is too high, causing the generator or detection element to vibrate. ； (2) Cavitation occurs in the pipeline ； (3) The generator or detection element is loose. Solution: In order to avoid damage to the generator or detection components, the valve should be adjusted first to reduce the flow rate and flow rate, and then further identify the cause. 10. Problems with model selection. Some vortex sensors have a larger size during caliber selection or due to changes in process conditions after design selection. In actual selection, the smallest caliber should be selected to improve measurement accuracy. For example, a vortex pipeline is designed to be used by several equipment. Because some process equipment is sometimes not used, the current actual flow rate is reduced. Actual use causes the original design selection diameter to be too large, which is equivalent to increasing the lower limit of measurable flow. The indication cannot be guaranteed when the flow rate of the process pipeline is small, but it can still be used when the flow rate is large, because it is sometimes too difficult to remodel. Changes in process conditions are only temporary. Solution: Can be combined with parameter re-adjustment to improve indication accuracy. 11. Reasons for the setting direction of vortex flowmeter parameters. Due to parameter errors, the instrument indication is incorrect. Parameter errors cause the secondary instrument full-scale frequency calculation to be incorrect. If the full-scale frequency is similar, the indication will be inaccurate for a long time. If the actual full-scale frequency is higher than the calculated full-scale frequency, the indication will fluctuate in a wide range and cannot be read. In addition, the inconsistency of the parameters in the data will affect the final determination of the parameters. Solution: Finally, the parameters were determined through recalibration and mutual comparison, and this problem was solved. 12. Secondary instrument failure. There are many faults in this part, including: Once the instrument circuit board had a disconnection, some bits of the range setting were broken, and some bits of the K coefficient setting were broken, making it impossible to determine the range setting and K coefficient setting. Solution: By fixing the corresponding fault, the problem is resolved. 13. Four-line connection problem. On the surface, some circuits appear to be well connected, but upon closer inspection, some connectors are actually loose and interrupt the circuit. Although some connectors are tightly connected, the fastening screws are tightened on the wire sheath due to secondary line problems, which also interrupts the circuit. Solution: Rewire. 14. Due to the fault of the flat-axis cable of the secondary instrument, the circuit always has no indication. Due to the long-term operation of the vortex flowmeter and the influence of dust, the flat-axis cable fails. Solution: By cleaning or replacing the flat shaft wire, the problem is solved. 15. Use environment issues. Especially the sensor part installed in the underground well, due to the high ambient humidity, the circuit board is affected by moisture. Solution: Through corresponding technical transformation measures, some sensors with high ambient humidity were re-separated from the probe part and the conversion part, and switched to separate sensors, thus improving the working environment. Currently, this part of the instrument is running well. 16. Due to poor on-site adjustment, or due to changes in the actual situation after adjustment. Due to poor on-site vibration and noise balance adjustment and sensitivity adjustment. Or the indication problem may be caused by changes in on-site conditions after a period of operation after adjustment. For more information, please visit the company’s official website http://www.yb1518.com/. 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