求一段西门子400cpu诊断含义

诊断信息如下：
Diagnostic buffer of module CPU 412-2 DP

Order No./ Description         Component                     Version                      
6ES7 412-2XJ05-0AB0           Hardware                       2                            
- - -                         Firmware                       V 5.1.1                      

Rack:                         0
Slot:                         3


Serial number: SVPVN398439


Event 1 of 44:  Event ID 16# 2943
I/O access error, writing
P area, double-word access, Access address:    356
FC number:     12
Module address:    344
Requested OB: I/O access error OB (OB122)
Priority class:  1
External error, Incoming event
07:23:21.012 AM  07/31/1996


Event 2 of 44:  Event ID 16# 2942
I/O access error, reading
P area, double-word access, Access address:    358
FC number:     12
Module address:    332
Requested OB: I/O access error OB (OB122)
Priority class:  1
External error, Incoming event
07:23:21.012 AM  07/31/1996


Event 3 of 44:  Event ID 16# 2942
I/O access error, reading
P area, word access, Access address:    356
FC number:     12
Module address:    324
Requested OB: I/O access error OB (OB122)
Priority class:  1
External error, Incoming event
07:23:21.012 AM  07/31/1996


Event 4 of 44:  Event ID 16# 2943
I/O access error, writing
P area, double-word access, Access address:    316
FC number:     12
Module address:    296

以上诊断信息是何意？是cpu本身出现问题还是与之通讯的站出现问题，或者是什么？谢谢！