What is the Difference between Electromagnetic and Ultrasonic Flow Meters?

Electromagnetic flow meters use the Faraday magnetic induction principle. The main structure of the electromagnetic flow meter consists of a magnetic circuit system, a measuring conduit, electrodes, a housing, a lining, and a converter. From a physical point of view, it has a strong anti-interference ability and is not affected by the viscosity, density, and pressure of the object. This type of flow meter is relatively common, and the production and maintenance technology is relatively mature.

Its advantages are corrosion resistance and wear resistance, and a long service life. It can perform bidirectional measurements and is easy to operate. Electromagnetic flow meters are now used in metallurgy, industry, chemical industry, agricultural irrigation, environmental protection, medicine and other fields. A typical example is the measurement of the volume flow rate of conductive liquids in closed conduits.

Ultrasonic flow meters use ultrasonic waves to measure the flow rate of liquids in pipelines. As early as the 1970s, ultrasonic flow meters have been widely used. Now, its technology is more mature and has a wider range of applications. The advantage of ultrasonic flow meters is that they can check the flow rate of fluids without contacting the measured object. The advantage is that no matter what the medium or the diameter of the pipeline is, it will not affect the working efficiency of the ultrasonic flow meter. Ultrasonic flow meters can detect gases and steam that electromagnetic flow meters cannot detect.

Troubleshootings of Electromagnetic Flow Meter- Battery Powered

The instrument has no display

Check whether the power is on.

Check whether the power supply voltage meets the requirements.

Excitation alarm

Is the excitation wiring open?

Is the total resistance of the sensor excitation coil matched with the converter excitation current?

If the first two items are normal, it is a converter failure.

Empty pipe alarm

Measure whether the measuring tube of the sensor is full of fluid.

Short-circuit the converter signal line (white core wire, red core wire, shielding wire). At this time, if the “air pipe” prompt disappears, it means that the converter is normal, which may be caused by the low conductivity of the measured fluid or incorrect setting of the air pipe threshold and air pipe range.

Check whether the signal connection is correct.

Check whether the sensor electrode is normal:

When the flow rate is zero, observe that the displayed conductivity should be less than 100%;

When measuring the flow rate, the resistance of the white and red core wires to the shielding wire should be less than 50kΩ (this measurement value is for water medium. It is best to use a pointer multimeter to measure, and the charging and discharging phenomenon can be seen during the measurement process).

Inaccurate flow measurement

Measure whether the measuring tube of the sensor is full of fluid;

Check whether the signal line connection is normal;

Check whether the sensor coefficient and sensor zero point are set according to the sensor label or factory calibration table;

Remote control button failure

If the remote control does not respond to the button when it is pointed at the infrared tube, it may be that the button battery voltage inside the remote control is insufficient. The remote control can be removed to measure the button battery voltage. If the button battery voltage is lower than 2.7V, it will not work properly and the button battery needs to be replaced.