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The intelligent converter, together with the electromagnetic flowmeter, forms an electromagnetic flowmeter used for flow measurement; therefore, before dealing with any faults in the converter, it is necessary to first confirm that the fluid flow in the pipeline, as well as the sensor and system wiring, are all in normal condition The instrument shows no display. a) Check whether the power supply is connected ； b) Check whether the power fuse is intact; the fuse should be replaced with one of the same model and specification ； c) Check whether the supply voltage meets the requirements ； d) Check whether the display’s contrast adjustment can be adjusted, and whether the adjustment is appropriate ； e) If items a), b), and c) mentioned above are all functioning properly, and f) no problems are detected, please send the converter to the manufacturer for repair. Electromagnetic flowmeter excitation alarm a) Are the excitation terminals EX1 and EX2 open-circuited? ； b) The total resistance of the sensor excitation coil should be less than 150Ω ； c) If both a) and b) are normal, then the converter is faulty. Airway and electrode alarm a) Check whether the fluid fills the sensor measurement tube ； b) Short-circuit the converter’s signal input terminals SIG1, SIG2, and SIG GND using a wire. If the “vacuum tube alarm” and “electrode anomaly” warnings are resolved, it indicates that the converter is functioning properly; this may be due to a low conductivity of the fluid being measured or the electrodes being covered by gas. c) Check whether the signal wiring of the electromagnetic flowmeter is correct ； d) For abnormal electrode conditions when the sensor is filled with fluid, use a 500-type analog multimeter set to the resistance ×1kΩ range to check the resistance of the sensor electrodes. Connect the red test lead of the multimeter to the electrodes, and the black test lead to the liquid-contact electrode (the liquid-contact ring or metal pipe). The pointer of the multimeter moves from left to right, indicating a value around 3–50 kΩ; thereafter it moves from right to left as discharge occurs. The difference in the movement of the two electrodes to the right should not exceed 20% – otherwise, it indicates that the electrodes are contaminated or covered. Using a digital multimeter, the DC voltage between the liquid-contact points of DS1 and DS2 (liquid-contact electrodes, liquid-contact rings, metal pipes) should be less than 1 V, and the DC voltage difference between the two electrodes should be below 50 mV. Otherwise, it indicates that the sensor electrodes are polarized. The upper limit alarm indicates that both the output current and the output frequency (or pulses) have exceeded the limits. Increasing the flow range can cancel the upper limit alarm. The lower limit alarm indicates that both the output current and the output frequency (or pulses) are out of range. Reducing the flow range can cancel the lower limit alarm. There is an error in the system settings. Intelligent judgments have been made regarding the flow range settings, the units used for flow accumulation, and the pulse equivalence settings, with suggestions provided to facilitate the adjustment of these settings. System self-check alarm: If a system self-check alarm occurs, please send the converter to the manufacturer for repair. The measured flow rate is inaccurate. a) Is the fluid being measured filling the sensor tube of the electromagnetic flowmeter, and are there any bubbles inside the tube? ； b) Is the signal cable connected properly, is the insulation degraded, and is the grounding in good condition? ； c) Check whether the sensor coefficients, sensor zero points, and factory calibration coefficients are set correctly according to the sensor label or factory calibration sheet ； d) Check the contact resistance between the sensor electrodes and the liquid, as well as whether the electrode insulation is adequate. Communication failure check: a) The performance of the 232/485 conversion interface is poor. The performance of conversion interfaces varies greatly among different manufacturers. b) The quality of the communication cable is poor. It must be twisted pair with a shielding layer; if it is ordinary parallel wires, the transmission distance will not be very far due to the effect of distributed capacitance, and the transmission speed will also be low. c) The communication cable is connected in the wrong position or reversed. d) The instrument address and baud rate of the host computer are different from those set in the instrument. e) The protocols are not the same; some protocols send commands in 2 bytes, while others send them in 4 bytes. f) When the communication distance exceeds 1000 meters, or when there is excessive electromagnetic interference at the site, repeaters should be added to enhance the communication capacity. g) During on-site testing, the computer is connected directly to the instrument via a short cable, which eliminates various factors such as interference from cables and the electromagnetic environment, allowing for quick assessment of the 232/485 interfaces, wiring, or communication protocols. 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