Electromagnetic flowmeter sensor output signal grounding should be electrically connected to the measured medium, which is a necessary condition for electromagnetic flowmeter work.
If this condition is not met, the electromagnetic flowmeter will not work properly, which is determined by the signal circuit of the sensor. When the fluid cuts the magnetic lines of force to generate a flow signal, the fluid itself is used as the zero potential, a positive potential is generated on one electrode, and a negative potential is generated on the other electrode, which changes alternately. Therefore, the midpoint of the converter input terminal (signal cable shielding layer) must be at zero potential and conductive with the fluid, so as to form a symmetrical input circuit. The midpoint of the converter input terminal is electrically connected to the measured fluid through the grounding point of the sensor output signal.
Electromagnetic flowmeter grounding precautions
(1) The grounding point of the instrument should be an independent grounding point and should not be connected to the grounding wire of other electrical equipment. The grounding resistance should be less than 10Ω, and some models of instruments are required to be less than 100Ω.
(2) When the sensor is installed on an insulated pipe, grounding rings must be installed at both ends, and then connected with wires to "conduct" with the fluid. If the conductivity of the measured medium is low, a metal short pipe can be used instead of the grounding ring to ensure the grounding effect. The function of the grounding ring is the same as the first one. The metal process pipeline is in direct contact with the medium, and the grounding wire is directly connected to the metal pipeline or flange, so there is no need for a grounding ring.
Hangzhou Economic Development Area，Hangzhou 310018，China
