Multi-sample Unit Preprocessing Platform and Its Control System Design

Abstract

Many complex samples must be preprocessed to analyze and detect. And sample preprocessed accounts for more than 60% of the entire sample analysis process. In order to improve efficiency and accuracy, an automated multi-sample preprocessing platform was designed and its automation control system was discussed. The functions of the platform mainly include: transferring 10 kinds of solvents, processing 96 samples, ultrasonic treatment, automatic cleaning. The control system of the platform is mainly composed of computer, PLC, syringe pump, distribution valve, sensor, stepping motor, ultrasonic pool, and the three-dimensional motion system. The platform adopts distributed control by LabVIEW and PLC, with friendly human-computer interaction interface and complete function. The platform selects six syringe pumps equipped with a dispensing valve to achieve the fluid transfer accuracy and efficiency requirements of the platform. The six syringe pumps are independent of each other, and the syringe range is 50μL~50ml.Its working mode divided into normal mode and micro-step mode, which can achieve high throughput and ensure its volume accuracy. Install some proximity switches on the 3D motion system to achieve zero and limit point positioning for each axis. The PLC compares the current position with the received position command to obtain the difference in orientation. Finally, the PLC sends the required pulses to the stepper motor driver, and the proximity switch can verify the sample position.