Event Detection
Table 2-3 shows how a DP Master CPU 31x-2 recognizes operating state
transitions of a DP Slave CPU or or data transfer interrupts.
Table 2-3
Event Detection of the CPU 31x-2 as DP Master
Event
Bus interruption
(short-circuit, plug
disconnected)
DP Slave
RUN → STOP
DP Slave
STOP → RUN
PLC S7-300, CPU Specifications CPU 312 IFM to CPU 318-2 DP
A5E00111190-01
CPU 31x-2 as DP Master/DP Slave and Direct Communication
What Happens in the DP Master
S
OB 86 is called and a station failure reported
(incoming event;
Diagnostic address of the DP slave, assigned to the DP
master)
S
on peripheral access: Call of OB 122
(Peripheral access error)
S
OB 82 is called and Module fault reported
(incoming event;
Diagnostic address of the DP slave assigned to the DP
master;
Variable OB82_MDL_STOP=1)
S
Call of OB82 with the message Module OK.
(outgoing event;
Diagnostic address of the DP slave assigned to the DP
master;
Variable OB82_MDL_STOP=0)
2-11