DDSY523 adopts large scale special logical circuit and is provided advanced selling electricity appliance and software. It can calculate AC single phase active energy with the rated voltage of 220V and the rated frequency of 50Hz. It has various functions of energy account, load control and customer¡¯ information  management, etc. It is an ideal product to reform the system of using electricity at present, to realize electric energy commercialization, to solve the problem to collect fees and to carry out actual time moni-tor and control in using electricity and adjusting the loading state of the electrical net.