【单选题】下面有关串级控制系统的描述,哪个是不正确的()
B.
串级控制系统主控制器一般采用PI或PID调节规律
【单选题】____ made the school proud was _____ more than 90% of the students had been admitted to key university .
【单选题】_____ made the school proud was _____ more than 90% of the students had been admitted to the key university.
【单选题】_____ made the school proud was ____ over 90% of the students had been admitted to key universities. [ ]
【简答题】主控阀一般采用___________或___________,一般为了保护回路,要求双控电控的换向阀两控制口不能同时有___________,即双电控的电磁阀不能___________。
【单选题】______ made the school proud was ____ more than 90% of the students had been admitted to the key universities.
【单选题】关于电液换向阀的以下说法错误的是( )
A.
外控是指辅泵或主油路分出的减压油路向导阀专用油孔供控制油
B.
内控是指由供给主阀的压力油经阀内油路向导阀控制供油
【单选题】关于电液换向阀的以下说法错误的是_____。
A.
外控是指由辅泵或主油路分出的减压油路向导阀专用油口供控制油
B.
内控是指由供给主阀的压力油经阀内油路向导阀供控制油