Polarization voltage detection circuit used in electromagnetic flow meter

Abstract

The invention relates to a polarization voltage detection circuit used in an electromagnetic flow meter. A resistor R1 and a resistor R2 are connected with a pin 3 of an operational amplifier U1. The resistor R2 is connected with a pin 4 of the operational amplifier U1, a pin 2 of a double-channel comparator channel one U2A and a pin 5 of a double-channel comparator channel two U2B. A measuring electrode PB is connected with a resistor R3. The resistor R3 is connected with a resistor R4 and a pin1 of the operational amplifier U1. The resistor R4 is grounded. A pin 5 of the operational amplifier U1 is connected with a positive supply VAcc. A pin 2 of the operational amplifier U1 is connected with a negative supply VAss. The pin 3 of the double-channel comparator channel one U2A is connected with a positive 1.2V. A pin 8 of the double-channel comparator U2A is connected with the positive supply VAcc. The pin 4 of the double-channel comparator U2A is connected with the negative supply VAss. A pin 6 of the double-channel comparator channel two U2B is connected with a negative 1.2V. By using the circuit, a user can timely maintain electromagnetic measurement of the electromagnetic flowmeter so that zero point stability of the electromagnetic flow meter can be ensured and correct measurement of the electromagnetic flow meter can be realized. The circuit is simple, economical and practical.

Description

technical field [0001] The invention relates to a circuit applied to the polarization voltage detection of an electromagnetic flowmeter. Background technique [0002] Since the electrode polarization will occur when the measuring electrode is in contact with the measured fluid, a slowly changing and random polarization voltage independent of the flow rate will be generated between the two measuring electrodes of the electromagnetic flowmeter. The magnitude and polarity of the polarization voltage are very random. At present, the electromagnetic flowmeter mostly adopts the low-frequency rectangular wave excitation method and cannot completely eliminate the polarization voltage. When the polarization voltage reaches a certain amplitude (usually 120mV Left and right) will submerge the flow signal of the reaction flow rate, which cannot reflect the flow rate, affects the zero point stability of the electromagnetic flowmeter, and cannot realize real measurement. Contents of the...

AI Technical Summary

Problems solved by technology

The magnitude and polarity of the polarization voltage are very random. At present, the electromagnetic flowmeter mostly adopts the low-frequency rectangular wave excitation method and cannot completely eliminate the polarization voltage. When the polarization voltage reaches a certain amplitude (usually 120mV Left and right) will submerge the flow signal of the reaction flow rate, which cannot reflect the flow rate, affects the zero point stability of the electromagnetic flowmeter, and cannot realize real measurement

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