SIEMENS 6DS1412-8DD这款PLC的硬件损坏概率很低，软件运行出错的概率也几乎为零。此外，其输入点如果不是强电入侵所致，几乎也不会损坏，而其输出继电器的常开点，若不是外围负载短路或设计不合理导致负载电流超出额定范围，其触点的寿命也很长。因此，查找电气故障点，重点要放在PLC的外围电气元件上。

The probability of hardware damage in this PLC is very low, and the probability of software errors is almost zero. In addition, if its input point is not caused by strong current intrusion, it will almost never be damaged, and if the normally open point of its output relay is not caused by external load short circuit or unreasonable design, which causes the load current to exceed the rated range, its contact life is also very long. Therefore, when searching for electrical fault points, the focus should be on the peripheral electrical components of the PLC.