The thermal insulated property of the freezing chamber of FPD-4A freezing point depression instrument was improved.The intelligent data acquisition software is designed,which can be used to automatically judge and inform the freezing point.The instrument performance was tested.According to the analysis of the test results of frozen power,it is found that the optimal freezing voltage should be the lowest voltage that can just make the system start to solidify.According to the analysis of the test results of ...