Puts forward the purpose & necessary on power down protection of NC system for machine tool,and emphasis on discussing it's method of software realization,low speed wire electrical discharge machineing(LSWEDM)machine tool for example.

The file access control,message authentication and data encryption for communication were designed,and the power down protection while modifying flash memory or update several files was introdued.

The hardware design scheme and software programming method for general power-off protection of measuring control system are introduced.

This paper describes the makeup and working principle of MAX691A supervisor circuits, and its application to the anti-interference and power-fail protection circuit of the 80c196kc single-chip micro controller system is presentedalso, as well as the hard ware connection circuit and the corresponding software design method .

By analyzing and contrasting several power-fail protection circuits in SCM,the paper puts forward a simple and reliable power-fail protection scheme for SCM.

The selection guideline of the electrolytic capacitor is given according to different key targets such as voltage ripple, capacitor s life time and power supply hold-up time.