发表于:2005/11/6 2:36:00
#40楼
很简单.利用按钮开关QA1的常开常闭各带一个接触器km1,km2. km2接触器串起动接触器km3常开点并自保,,km1常开串km4常闭起动km3并自保,km1, km2两常开串连接km4就ok
QA1按下---KM1---KM3闭合自保
QA1复位---km1释放---KM2闭合自保
QA1按下---KM1---KM4闭合---km3释放
QA1按下---KM1---KM3闭合自保
QA1复位---km1释放---KM2闭合自保
QA1按下---KM1---KM4闭合---km3释放