A.101通信規(guī)約 B.104通信規(guī)約 C.Modbus RTU D.CDT規(guī)約
A.交換機(jī)故障 B.網(wǎng)絡(luò)故障導(dǎo)致數(shù)據(jù)庫(kù)不可訪問(wèn) C.交換機(jī)端口故障 D.顯示系統(tǒng)中的某臺(tái)主機(jī)斷網(wǎng),且刷新時(shí)間不更新
A.24V B.48V C.380V D.220V