Causes of failures in Yokogawa electromagnetic flowmeters
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The Yokogawa SE14N electromagnetic flowmeter is used to measure water. It has been in use for many years, with a pipe diameter of 300 MM and a measurement range of 500 CUM/H. The liquid flows normally through the pipeline; currently, the measured values are –8% and –40 CUM/H. After reversing the direction of flow in the flowmeter, the values become around 15% and 70 CUM/H. The flow velocity as detected by the flowmeter is 1.964 M/S in both directions. Additionally, if the excitation wires are reversed, the values still remain around 15% and 70 CUM/H. Why does reversing the excitation wire affect the flow indication, and why is the effect the same as when changing the direction? Also, the detection speed is the same in both forward and reverse directions; what’s the use of this speed? Can the actual value be calculated from it? When the power is turned off, the resistances between signal lines A, B, and C are 1.5 megohms and 3.5 megohms respectively.
Don’t overthink it; promptly remove the flow meter to clean the electrodes and check whether the electrode linings are intact. If the problem persists after reinstallation, then examine the excitation system and the circuit board.
It’s in use currently, and there’s no bypass; it can only be taken apart during maintenance time
Will there be dissatisfaction with management? I’ve encountered similar situations before