Is there a difference between a two wire ultrasonic level meter and a three wire ultrasonic level meter?

The two wire ultrasonic level meter shares the same circuit for power supply (DC24V) and signal output (DC4-20mA), using only two wires. It is a standard transmitter form, but the disadvantage is that the transmission power is relatively slightly weaker.

The three wire ultrasonic level meter is actually a four wire system, with its power supply (DC24V) and signal output (DC4-20mA) circuit separated, each using two wires. When their negative terminals are connected to ground, usually three wires are used. Its advantage is that it has a higher transmission power.

What is the blind spot of ultrasonic level meters?

Ultrasonic level meters cannot simultaneously detect reflected echoes when emitting ultrasonic pulses. Due to the time width of the emitted ultrasonic pulse and the residual vibration of the sensor after the ultrasonic wave is emitted, the reflected echo cannot be detected during this period. Therefore, a small distance from the probe surface downwards cannot be detected normally, which is called a blind spot. If the highest level being measured enters a blind spot, the instrument will not be able to detect it correctly and there will be errors. If necessary, the level gauge can be installed higher.

What are the most important issues to pay attention to when selecting engineering designs?

Choose a good installation location and design a suitable installation interface.

① The installation position should be chosen as much as possible with a stable liquid level and a flat material surface, while staying away from the escalator, feed inlet, and discharge outlet. It should also be kept as far away from the container wall as possible and away from the mixer.

② The installation interface requires a sufficiently large opening size. When installing with a flange, the length of the connecting pipe under the flange should be designed reasonably. For our company's 10 meter and 12 meter range level meters, the length of the connecting pipe should not exceed 15cm. Choose a flange with a diameter of DN80 or above. For level meters with ranges of 15 meters, 20 meters, 30 meters, and 40 meters, the length of the connecting pipe should not exceed 20cm; Select flange ports with a diameter of DN200 or higher. For level meters with a range of less than 8 meters, there is no requirement for the length of the connecting pipe. It can be designed appropriately to eliminate the influence of blind spots, and flange ports above DN65 can be selected.