Considering this problem from the angle of institution,we can find that the defect or insufficient supply of system are important factors causing environmental condition of our country deteriorating,which are owner-ship system,market trade system,basic control system of environmental resource.

The performance of its basic controller decides the operation condition of HVDC system.

Taking the vocational education in Belgium for example,th e article introduces the basic system of vocational education,and then analyses the basic system of voca-tional education in Holland,which involved vocationa l proparatory education,secondary vocational education and higher vocational ed ucation,and expounds the implications which the development of Chinese v.

Governing the country by law,as a basic system in our country,has its forming indexes as follows:1)a complete system of socialist laws;2)a sound system of democracy and supervision;3)a rigid executive law system and a just judicature system;4)a high-qualified team in executing law;5)the raising of the nation s sense of legal system.

By analysis the to basic system of enviromental law comprehensively in law field and the academic field,It establishes six basic systems.

The checking items have basic control point,near shaft point for orientation and elevation starting point,shaft mouth coordinate,underground traverse point and elevation starting point,underground roadway and productive workings extension.

This paper presented a small scale distributed control system based on RS 485 which links PC and several distributed control system basic controllers.