Liquid Surface Tension Detection System Based On PLC Control

Surface tension is a kind of important physical properties of liquid material, which is also the important characterization parameter of fluid interface problems. It is very crucial to measure the surface tension of the liquid material in the field of material production and performance identification accurately.In this paper, we designed a surface tension detection system based on PLC (Programmable Logic Controller) control. The system improved the surface tension detection device using the maximum bubble pressure method in pressure to generate means and micro-pressure measuring device. It also increased the temperature control device and the MCGS (Monitor and Control Generated System) operation interface. The system has the characteristics of high precision, intelligent controllable, data analysis convenient, easy development and maintenance.The main research contents include:(1)We studied the advantages and disadvantages of the control method for measuring surface tension using the maximum bubble pressure method. The PLC was used to achieve a new surface tension detecting device which had supplied stable pressure control function, temperature control function, data storage function.(2)The hardware and software was designed for the system. The hardware mainly includes the selection of PLC, port assignments, pressure supply unit, the temperature control unit, data collection and transfer unit, etc. The software includes GX Developer programming software, part of the PLC program written in GX Developer, the operation interface structure of MCGS touch screen, the setting of MCGS and the function of each part.(3)The test results of the system and performance were analysis. Using the known surface tension of the material, such as distilled water and other substances as test samples. The system parameters are obtained by comparing the results of the experimental surface tension values detected by the design of system with standard values.The system test results have shown that the surface tension test system based on PLC can complete the real-time control of the module and meet the main technical indicators, the test requirements. It also can accurately measure the surface tension of the liquid material surface tension value, whose temperature is above normal and the size of the liquid material is within 100mN/m and the measurement accuracy is not less than 0.01%.