Development Of A Solution Freezing Point Measuring Instrument Based On MSC1210

Freezing point is the temperature when solid becomes liquid or liquid becomes solid, namely the balance temperature between liquid and solid state. The freezing point of a solution changes with its concentration. Usually, the higher the concentration is, the lower the freezing point becomes. The freezing point measuring instrument we have developed is an instrument which is used to measure the freezing point of solution. It is important to medicine research, production, application and food sanitation. At present, most commercially available instruments'resolution is lower and their size is bigger.The solution freezing point measurement is based on Raoult's law, which describes the direct ratio relationship between drop value of freezing point of a solution and its molar concentration. The instrument is characterized by automatic operation, high efficiency, high resolution and low power dissipation. Its hardcore controller is MCS1210, which has a high efficient 24-bit ADC in it, so comparing with other freezing measuring instruments, it is more precise and has smaller size.The main work of the thesis includes the following aspects:1. Study the principle of solution freezing point measurement instrument, expatiation of Raoult's law and relationship between drop value of freezing point of a solution and its osmotic pressure molar concentration.2. Design acquirement and transform part of the sample temperature value, surveillance and control part of refrigeration, drive and position part of mechanism, calendar part, operation part and export part.3. Debug the hardware and software of the instrument. Inspect the parts which may accident seriously, such as surveillance and control part of refrigeration and drive and position part of mechanism. Make sure the instrument will run all right.4. Calibrate the instrument with standard solution which we have known its concentration. Measuring the voltage when the standard solution is icing and fitting a curve with freezing point and voltage, we will know the relationship between the voltage and osmotic pressure molar concentration.5. Measure other standard solution we have not used, test the repeatability, accuracy and resolution, and analyze the factors which have affectde the measuring results.6. The problems which are still exist and what we should do next.