Maybe this can help:
Module Information - CPU 314 "Diagnostic Buffer" Tab
Event 1 of 10: Event ID 16# 2942
I/O access error, reading
P area, word access, Access address: 384
Requested OB: I/O access error OB (OB122)
Priority class: 1
External error, Incoming event
08:22:50.122 AM 05/07/2011
Event 2 of 10: Event ID 16# 2942
I/O access error, reading
P area, word access, Access address: 384
Requested OB: I/O access error OB (OB122)
Priority class: 1
External error, Incoming event
08:22:50.113 AM 05/07/2011
Event 3 of 10: Event ID 16# 2942
I/O access error, reading
P area, word access, Access address: 384
Requested OB: I/O access error OB (OB122)
Priority class: 1
External error, Incoming event
08:22:50.106 AM 05/07/2011
Event 4 of 10: Event ID 16# 2942
I/O access error, reading
P area, word access, Access address: 384
Requested OB: I/O access error OB (OB122)
Priority class: 1
External error, Incoming event
08:22:50.098 AM 05/07/2011
Event 5 of 10: Event ID 16# 2942
I/O access error, reading
P area, word access, Access address: 384
Requested OB: I/O access error OB (OB122)
Priority class: 1
External error, Incoming event
08:22:50.089 AM 05/07/2011
Event 6 of 10: Event ID 16# 2942
I/O access error, reading
P area, word access, Access address: 384
Requested OB: I/O access error OB (OB122)
Priority class: 1
External error, Incoming event
08:22:50.082 AM 05/07/2011
Event 7 of 10: Event ID 16# 2942
I/O access error, reading
P area, word access, Access address: 384
Requested OB: I/O access error OB (OB122)
Priority class: 1
External error, Incoming event
08:22:50.064 AM 05/07/2011
Event 8 of 10: Event ID 16# 2942
I/O access error, reading
P area, word access, Access address: 384
Requested OB: I/O access error OB (OB122)
Priority class: 1
External error, Incoming event
08:22:50.056 AM 05/07/2011
Event 9 of 10: Event ID 16# 2942
I/O access error, reading
P area, word access, Access address: 384
Requested OB: I/O access error OB (OB122)
Priority class: 1
External error, Incoming event
08:22:50.049 AM 05/07/2011
Module Information - CPU 314 "Diagnostic Buffer" Tab
Event 10 of 10: Event ID 16# 2942
I/O access error, reading
P area, word access, Access address: 384
Requested OB: I/O access error OB (OB122)
Priority class: 1
External error, Incoming event
08:22:50.040 AM 05/07/2011