Design Of Viscosity Measurement System Based On CPLD Technology

Viscosity is an important parameter which affects the quality of products,manufacture technique and manufacture efficiency for many industries. In China,the measuring method of viscosity has fell behind and the precision and speed ofmeasurement are low. All of those are unable to meet the high demands for rapidand exact measurement. The foreign countries have mature viscosity measurementtechnology, advanced theory and high-quality products, however, its price isexpensive and technology is confidential. Therefore, it has great practicalsignificance to design a new viscosity measurement instrument which has easieroperation, higher precision and automation.This paper designs a viscosity measurement system based on CPLD technology.The system utilizes grating torque sensor to measure the torque angle caused byviscous force in the elastic axis, and obtains liquid viscosity values through thecalculation of MSP430F149. CPLD finishes the task of measuring phase difference,driving stepper motor, controlling the rotating speed of stepper motor and judginguniform. Thermostatic water bath module measures the temperature of the liquid byplatinum resistor named Pt100. The system controls liquid temperature withcomposite power mode. It stabilizes the temperature of the liquid to be measured inthe set value quickly, and reduces the impact of ambient temperature on the viscositymeasurement accuracy. Keys are used to set the system constant, rotating speed ofmotor, temperature of the liquid. The display unit displays the viscosity values andassociated parameter of the liquid to be measured.The design improves the traditional rotary viscosity measurement technology.Taking advantage of CPLD’s characters of high-speed, high integration density andlogical ability, the viscosity measurement system has more stable performance,wider measurement range and higher measurement reliability. The development ofviscosity measurement system with independent intellectual property rights, not only can create a certain degree of economic and social benefits, but also has someguiding significance for the future design of viscosity measurement system.