诊断后，看帮助如下：

Help on Event 4x6F

Des cription of Error:
A rack or a DP station has failed but the corresponding OB (OB86) or FRB is either not loaded or has not been activated.

S7-400:
If a user program was interrupted by this STOP event, the point of interruption in the program is specified in the detailed information.

To Correct or Avoid Error:
Load an OB86 or activate an FRB to react to the rack or station failure.

M7:
FRB = Function Request Block, relates to M7
The task ID is listed in the detailed information.

有2个问题：
1.我现已添加了OB86，是否还有其他的办法（如果无效，今天刚加），这个报警是什么东西损坏了，或者说，是什么原因引起的？
2.帮助中FRB 到底是什么，我本来也想加的，但找不到？
请各位帮我看下，先谢谢了！