有一个系统 能正常运行，但是 报错

点击“help on event”

后 提示如下 但是我还是不明白 请高手指点 

如果在CPU x1 口 插入 PC ADAPTER 编程适配器 则 报警消失，两个错误灯也熄灭

观察 模块信息 产生新的 事件 6881

上传 事件记录如下

Event 1 of 120:  Event ID 16# 6881

Interface error leaving state 

Interface ID: X1, MPI/DP/PROFINET

Operating mode: RUN

External error, Outgoing event

03:31:11.382 PM  05/24/2017

Event 22 of 120:  Event ID 16# 6981

Interface error entering state 

Interface ID: X1, MPI/DP/PROFINET

Operating mode: RUN

External error, Incoming event

03:08:37.556 PM  05/24/2017

Event 23 of 120:  Event ID 16# 4302

Mode transition from STARTUP to RUN

Startup information: 

- Time for time stamp at the last backed up power on

- Single processor operation

Current/last startup type:

- Cold restart triggered via MPI

Permissibility of certain startup types: 

- Manual warm restart permitted

Last valid operation or setting of automatic startup type at power on:

- Cold restart triggered via MPI

Previous operating mode: STARTUP (cold restart)

Requested operating mode: RUN

Incoming event

03:04:22.140 PM  05/24/2017

上述信息是通过cp5711 通过另外一个DP口 读取到的cpu模块信息。

请问 高手 事件6881 和 6981  到底是 咋回事？？