ABSTRACT
Objective:To design the liquid level detection system by ultrasonic method to meet the requirements of automatic enzyme immunoassay workstations and have a precise detection of liquid level. Methods:Because the existing sample needle should move down, liquid surface and the poor conductivity of liquid were invalid. So a method of ultrasonic liquid level detection system was designed. The control signal was launched by a microprocessor to control ultrasonic signal generator chip and the ultrasonic signal reflected when the liquid level in a test tube or microplate. Results: By receiving the reflection echo signal sent to the microprocessor for signal processing, the liquid level was detected. Conclusion: The ultrasonic method applied to the liquid level detection system to overcome the above shortcomings, improve pipetting accuracy and avoid cross pollution, so as to meet the requirement of the automatic enzyme immunoassay workstation test.