Design Of Intellectual Viscometer Based On Gravity-capillary

Viscosity measurement plays an important role in the petroleum, chemical, transportation, and other areas of national economy. However, most of the current domestic instruments based on capillary viscosity measuring need to manually time, less automation than imported equipment which is rather expensive. In this thesis, an intelligent viscometer is introduced, which is equipped with photodiode for accurate liquid level measurement and MSP430F449 with super low power for information processing.In this thesis, based on the digital temperature sensors DS1624, a method for adaptive dynamic compensating was presented, which can improve the ratio of response time by 30-40%. An improved temperature control algorithms is described, which included Bang-Bang control, fuzzy control, and PWM control, and make the accuracy of water tank temperature control is 0.05℃. A kind of liquid level detection method derivation from the least-squares linear regression and Romanowski is proposed, by which the repeatability of group is superior to 0.35%. Besides, the PC software design is developed by virtual instrument software LabVIEW, which have a friendly interface in managing all the measure information.The thesis is divided into six chapters. In chapter 1, the definition of viscosity is introduced, and then the work focus of the project is made clear after analyzing the existing viscosity automatic measurement status quo. In chapter 2, the structure and workflow of the intelligent viscometer based on the capillary gravity are introduced. In chapter 3, based on the digital temperature sensors, heating and refrigeration power equipments, an improved temperature control algorithms is described, which included Bang-Bang control, fuzzy control, and PWM control, besides, how to set parameters of the controller is discussed. In chapter 4, based on the photoelectric sensor and RTC Chip, a kind of liquid level detection method derivation from the least-squares linear regression and Romanowski is proposed. In Chapter 5, the man-machine interfaces are introduced, including serial LCD modules SO12864-17A, micro-thermal printers T1ARD0-20E325, and the PC software design developed by virtual instrument software LabVIEW. In chapter 6, error sources and processing method are explained, and the three aspects of the reliability such as ant jamming design, self-inspection and low-power design are suggested, followed by a brief introduction of engineering design for the instrument. The experimental results indicate that all the indicators of the instrument can reach and even be superior to the demands of the national standard for industrial viscometer, of which the timing error is less than 0.5%, the repeatability of group is superior to 0.35%, and the accuracy of water tank temperature control is 0.05℃. The instrument is used with easy operation, good accuracy and high intelligence degree. With the guarantee of advanced technology, the price of instrument is competitive. With the extensive application of the project, the industry will progress and the regional economy will have a positive role in promoting.