Handling of common faults in electromagnetic flowmeters in the device I work on

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I will now provide some summaries of the common faults and improvements related to Rosemount meters used in the positions we maintain, for everyone’s reference and discussion. 1. Faults that occur during operation after it has been running normally for a period of time – namely the types of faults commonly seen in routine maintenance – can be analyzed and diagnosed by using the self-diagnosis function, which displays fault information on the instrument to identify the location of the issue. The common faults of electromagnetic flowmeters and their corresponding solutions are as follows: (1) The indicated value does not match the actual flow rate, which is a common issue in routine maintenance. First, check that the grounding is in good condition and ensure that the flow meter is used with a full pipe. If there are no problems, check whether there is a valve on the upstream side near the instrument, as if the valve located upstream of the instrument is partially open, the instrument readings may be affected by disturbances. When all these are normal, check whether the converter is functioning properly, focusing on parameters of the instruments and calibration codes, etc. If there is a fault with the electrodes, it must be handled by the manufacturer. (2) Zero-point instability check: Verify whether there is a gas-liquid two-phase mixture inside the sensor, and check for valve leakage; if the valve is leaking, replace it. If all the preceding checks confirm that the instrument grounding is proper, i.e., that the resistance is less than or equal to 100 ohms. Check whether there is any accumulation in the liquid; if so, remove any dirt and scale from the electrodes and their surrounding area. (3) If there are no instructions, check the converter display or LED for blinking to see if any fault alarms are displayed. Examine the alarm codes to identify the location of the fault. If no faults are indicated, check whether the fuse is blown; if so, replace the fuse. If all of the above are normal, ensure that the fluid flows in the same direction as the arrow on the flow meter. (4) The continuous decrease in the LCD digital display is mainly due to a decline in insulation or a problem with one of the integrated components in the converter. The solution is that the coils inside the housing are not properly sealed, allowing water to enter and causing a decrease in insulation. 2. For the Shenhua facilities that we maintain, as they are located in the north where winters are long and cold with prolonged periods of freezing, it is essential to pay close attention to any water leaks when maintaining the instruments. As a result of these leaks, three instruments were damaged over a period of five months, from November 2007 to April 2008. So I would like to make a few simple suggestions regarding the points to pay attention to in the daily maintenance of Rosemount meters. (1) Perform calibration at the “0” position: Close the downstream shut-off valve to fill the pipeline with the medium, and then check the “0” position. (2) Setting of main parameters: The main parameters include upper and lower limits, range, unit, and pipe diameter. (3) Water resistance: A O-ring is added to the cover to prevent water from seeping in. The surface of B is coated with solidified transformer oil. If water does get into the watch, it must be taken out of service and dried using a hair dryer. The above are some of my summaries; I hope friends from Haichuan will offer their criticism and suggestions.