| 摘要 |
PURPOSE: To easily and always stably carry out the judgement of presence of a liquid even for materials for liquid tanks and liquids whose receiving wave levels of ultrasonic waves differ based on the types of materials and the kinds of the liquids. CONSTITUTION: An ultrasonic level meter is composed of a sensor head 3 which produces ultrasonic waves by high frequency signals from a transmission circuit 4 and transmits the waves to a liquid tank 1 and receives the reflected waves of the transmitted waves, a receiving circuit 6 to process the received waves of the sensor head 3, a comparison circuit 7 to compare the output of the receiving circuit 6 with a standard voltage, a counting circuit 8 to count the outputs of the comparison circuit 7 per time, and a bar light emitting display apparatus 12 having a plurality of light emitting elements which turn on and off corresponding to the counted value of the counting circuit 8. The gain adjustment 13 of the reception circuit 6 is carried out by turning on and off states of a plurality of the light emitting elements of the bar light emitting display apparatus 12 and alteration of the standard voltage of the comparison circuit 17. |
