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A vortex flow meter refers to the use of HLUG series intelligent vortex flow meters, which are primarily used for measuring the flow rate of fluids in industrial pipelines, including various media such as gases, liquids, and vapors. It is characterized by low pressure loss, a wide measurement range, and high accuracy; when measuring volumetric flow rate under operating conditions, it is hardly affected by parameters such as fluid density, pressure, temperature, and viscosity. There are no moving mechanical parts, thus it offers high reliability and requires minimal maintenance. The instrument parameters can remain stable over the long term. This instrument uses piezoelectric stress sensors, offering high reliability, and can operate within a working temperature range of -20°C to +250°C. It provides both analog standard signals and digital pulse signals for output, making it easy to integrate with digital systems such as computers; it is a relatively advanced and ideal flow meter. The main problems are mainly: ① The indications are inaccurate over the long term ； ②No instructions at all ； ③Indicates large fluctuations; no reading possible ； ④Indicate not to return to zero ； ⑤No indication at low flow rates ； ⑧The indication is okay at high flow rates, but inaccurate at low flow rates ； ⑦The indication fails to keep up when the flow rate changes ； ⑧The K coefficient for the instrument cannot be determined, as there are inconsistencies in various sources. Analysis and resolution of major issues: Analyzing and resolving these issues took nearly half a year. Due to the complexity of the problems, there were issues of varying degrees in design and installation, parameter setting, daily maintenance, and the operating environment; many of these problems were interrelated. Additionally, resolving some issues required waiting for certain conditions to be met during the operation process, which posed significant difficulties in addressing them. Some issues were caused by multiple factors, with each factor being related to several different problems. Summarizing the main reasons for these problems, they mainly relate to the following aspects: 1. Issues with product selection. Some vortex flowmeter sensors, either during the selection of the diameter or after the design phase due to changes in manufacturing conditions, end up having a larger specification chosen than necessary; in fact, the smallest possible diameter should be selected to improve measurement accuracy. The reasons for this are mainly related to issues ①, ③, and ⑥. For example, a vortex street pipeline is designed to serve several devices; since some of the equipment in the process system is not used at times, the actual flow rate in use is reduced. This results in the originally selected pipe diameter being too large, which in turn raises the lower limit of the flow rate that can be measured. The gauge cannot provide accurate readings when the flow rate is low, but it still functions properly when the flow rate is high. After all, it is too difficult to carry out modifications in such cases. Changes in process conditions are often only temporary. The indication accuracy can be improved by adjusting the parameters. 2. Issues with installation. Mainly, the length of the straight section in front of the sensor is insufficient, which affects the measurement accuracy; this issue is primarily related to problem #1. For example, the straight pipe section in front of the sensor in the second circulation circuit, FIC203, is clearly insufficient. Since FIC203 is not used for measurement but only for control, the current accuracy can be considered as equivalent to a reduced-grade version of its performance. 3. Reasons for the parameter tuning direction. Due to incorrect parameters, the instrument readings are inaccurate. These parameter errors result in an incorrect calculation of the full-scale frequency of the secondary instrument; the reasons for this are mainly related to issues ① and ③. A significant difference in the full-scale frequency leads to inaccurate readings over time; when the actual full-scale frequency is much higher than the calculated value, the readings fluctuate greatly and become unreadable. Moreover, inconsistencies in the parameters listed in the documentation affect the final determination of these parameters. This issue was resolved by performing re-calibration and making comparisons between different values. 4. Secondary instrument failure. There are many faults in this area, including broken wires in the primary instrument circuit boards, faulty display of individual bits related to range setting, and faulty display of individual bits related to K-factor setting, which makes it impossible to determine the range setting and the K-factor value. These issues are mainly related to problems① and②. The problem was resolved by fixing the corresponding fault. 5. Issues with the connection of four circuits. On the surface, the wiring in some circuits appears to be properly connected; however, upon closer inspection, it is found that some connectors are actually loose, resulting in interruptions in the circuit. In other cases, although the connectors are tightly fitted, issues with the auxiliary wires cause the fastening screws to tighten around the wire insulation, which also leads to circuit interruptions. These problems are mainly related to issue #2.