当检测到电压有波动的时候设备会跳掉，但是点启动后马上回恢复。
出现如下错误信息，OB122已经下到程序里了，是CPU停机了么？还是其他原因，为什么会出现I/O接口错误呢。。
Event 1 of 120: Event ID 16# 38C4
Distributed I/Os: station return
Address of the affected DP slave: station number: 8
DP master system ID: 1
Log. base address of the DP slave: Input address: 8176
Log. base address of the DP master: 8191
Requested OB: Rack failure OB (OB86)
Priority class: 25
External error, Outgoing event
03:57:23.874 AM 05/26/2014


Event 2 of 120: Event ID 16# 2943
I/O access error, writing
P area, word access, Access address: 658
FB number: 7
Module address: 212
Requested OB: I/O access error OB (OB122)
Priority class: 1
External error, Incoming event
03:57:23.873 AM 05/26/2014


Event 3 of 120: Event ID 16# 2942
I/O access error, reading
P area, word access, Access address: 662
FB number: 7
Module address: 80
Requested OB: I/O access error OB (OB122)
Priority class: 1
External error, Incoming event
03:57:23.873 AM 05/26/2014


Event 4 of 120: Event ID 16# 2942
I/O access error, reading
P area, word access, Access address: 666
FB number: 8
Module address: 12
Requested OB: I/O access error OB (OB122)
Priority class: 1
External error, Incoming event
03:57:23.873 AM 05/26/2014