cause:
1 monitoring time is too short.
2 dc link voltage is not present .
3 associated infeed or drive of the signaling component is defective.
4 supply voltage incorrectly set
我S120参数的monitoring time 为6000MS,和supply voltage为600V,两个参数都是默认的没有改过,应该不是1和4的问题吧,我想问一下在2中怎样可以知道有没有DC LINK,和第3条是怎样理解的