How large is the millivolt signal detected by an electromagnetic flowmeter?
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Experts, may I ask what the voltage signal measured by an electromagnetic flowmeter is? Hundred millivolts level? If the millivolt signal output by the sensor electrode is taken directly without any processing, wouldn’t interference cause significant issues during long-distance transmission? I would also appreciate some guidance from those who are more experienced!
Since electromagnetic flowmeters already exist, why go to the trouble of extracting millivolt signals? The reason current signals are used in industry is that voltage signals, especially those at the millivolt level, face significant limitations when transmitted over long distances. How far do you think a thermocouple signal can be transmitted? It is still a DC signal. The induced potential in an electromagnetic flowmeter can be alternating current, which increases the likelihood of external interference, as there is also the effect of inductance in the circuit. Your electromagnetic flowmeter is such a weird one – it doesn’t even have an electrical current output?
Voltage signals are not suitable for long-distance transmission; nowadays, instruments generally provide current output.