During the test of medical and chemical process, operators need to precise and repeated sampling operation of various liquid frequently. This paper designs a kind of automatic sampling control device based on PLC and the stepper motor's, and introduces the hardware and software structure of the system. This system can realize the pre washing, accurate positioning, sample number and sample volume settings, and has a touch screen for man-machine interface, which can be widely used in the field of precise experimental sample needs.

product is developed on the basis of the technical cooperation projects of the shandong xinyuan Thai letter electronic technology co., LTD.,using the luoyang LanFei PLC and touch screen, and spectrophotometer. It is easily to realize Add sample, full automatic measurement and report. A dose, dose and dose of antibiotics and other method can be realize.

Many disadvantages exist in human intravenous infusion preparation process, with cross contamination. Effectively prevent intravenous fluids should be dispensed pollution, this paper introduces the automatic dispensing device structure and working principle of the control system, the experimental results show that this system operation is simple, dissolution and improve the quality of the infusion preparation with high efficiency.