First, overview

Intelligent electromagnetic flowmeter is based on Faraday's law of electromagnetic induction, used to measure the volume flow of conductive liquid with conductivity greater than 5μS/cm, is a kind of induction instrument to measure the volume flow of conductive medium. In addition to measuring the volume flow of general conductive liquid, it can also be used to measure the volume flow of strong corrosive liquid such as strong acid and strong base and uniform liquid solid two-phase suspension such as mud, pulp, paper pulp. Widely used in petroleum, chemical, metallurgy, textile, paper, environmental protection, food and other industrial departments and municipal management, water conservancy construction, river dredging and other fields of flow measurement.

Two, the working principle

According to Faraday's principle of electromagnetic induction, a pair of detection electrodes are installed on the wall of the tube perpendicular to the axis of the measuring tube and the line of magnetic force. When the conducting liquid moves along the axis of the measuring tube, the conducting liquid cuts the line of magnetic force to generate the induced potential, which is detected by the two detection electrodes. The value is directly proportional to the flow rate, and its value is:

E=KBVD

Where:

E-induced potential;

K- coefficient related to magnetic field distribution and axial length;

B- magnetic induction intensity;

V- average velocity of conducting liquid;

D- electrode spacing; (Measuring tube diameter)

The sensor takes the induced potential E as the flow signal and transmits it to the converter. After a series of digital processing through amplification, transformation and filtering, the instantaneous flow and cumulative flow are displayed by dot matrix LCD with backlight. Converter has 4 ~ 20mA output, alarm output and frequency output, and is equipped with RS-485 communication interface, and support HART and MODBUS protocol.

Three, instrument characteristics

■ Full digital processing, strong anti-interference ability, reliable measurement, high accuracy, flow measurement range up to 150:1;

■ Ultra-low EMI switching power supply, suitable for a wide range of power supply voltage, good anti-EMI performance;

■ Adopt 16-bit embedded microprocessor, fast operation speed, high precision, programmable frequency low frequency rectangular wave excitation, improve the flow measurement

Stability, low power consumption;

■ SMD devices and surface mount (SMT) technology, high circuit reliability;

■ No moving parts in the pipeline, free flow parts, almost no additional pressure loss in the measurement;

■ The range can be modified online according to the actual needs of users on site;

■ The measurement results are independent of velocity distribution, fluid pressure, temperature, density, viscosity and other physical parameters;

■ High definition backlit LCD display, full Chinese menu operation, easy to use, easy to operate, easy to learn and understand;

■ With RS485, RS232, Hart and Modbus digital communication signal output; (Optional)

■ It has the function of self-test and self-diagnosis;

■ Hourly total metering function, hour as a unit to record the total flow, suitable for time-sharing measurement system (optional);

■ Three internal integrators can display the positive cumulant and the reverse cumulant and the difference cumulant respectively. The internal clock is provided with no power failure and can be recorded

Record 16 power outages. (optional);

■ Infrared handheld operator, 115KHZ communication rate, remote non-contact operation converter all functions (optional).