关键词: 仪表及控制系统接地，保护接地，仪表工作接地，接地连接方式，星型接地，网状接地，共用接地系统, Instruments and Control System，Protective earthing，Instrument common earthing，Bonding modules，Star Bonding，Net Bonding，Common Use Earthing System

Abstract: Abstract：The three actions of protect earthing and the three actions of common bonding for instruments and control system earthing purpose are introduced in the article. As earthing functions, earthing types can consist of protect earthing, instrument common earthing, shield earthing, intrinsical earthing, electrostatic protective earthing, lightning protective earthing, etc. According to basic concept, working principle and electrical property, earthing schemes such as star bonding，net bonding and star-net mix bonding are introduced and benefit of net bonding. According to principle of safety power utilization, it is recommend that equipotential bonding and electricity common earthing system. Engineering methods and bonding types of earthing are discucced. Anti electrical disturb effects and earthing philosophy and notes are discucced that often used methods for engineering design and implement.