Siemens Simatic S7-300 CPU 315-2-PN/DP - Interrupts on the DP Master

Debugging functions, diagnostics and troubleshooting
10.7 Diagnostics of DP CPUs
S7-300, CPU 31xC and CPU 31x: Installation
Operating Instructions, Edition 08/2004, A5E00105492-05
10-25
Evaluation in the user program
The table below shows an example of you how you can evaluate RUN-STOP transitions of
the DP master in the DP slave (see also the previous table).
Table 10-14 Evaluating RUNSTOP transitions in the DP Master/DP Slave
In the DP master In the DP slave
Diagnostic addresses: (Example)
Master diagnostic address = 1023
Slave diagnostic address in the master
system= 1022
(Slot 0 of slave)
(Diagnostic) address for "Slot 2"= 1021
(Slot 2 of slave)
Diagnostic addresses: (Example)
Slave diagnostic address = 422
Master diagnostic address = irrelevant
CPU: RUN → STOP The CPU calls OB82 with the following
information, for example:
• OB82_MDL_ADDR:= 422
• OB82_EV_CLASS:=B#16#39 (incoming
event)
• OB82_MDL_DEFECT: = Module error
Tip: The CPU diagnostic buffer also contains this
information
10.7.3 Interrupts on the DP Master
Interrupts with S7 DP master
Process interrupts from an intelligent slave with SFC 7
In the CPU 31x-2 operating in DP slave mode, you can trigger a user-defined process
interrupt from the DP master from the user program.
A call of SFC 7 "DP_PRAL" triggers the execution of OB 40 in the user program on the DP
master. The SFC 7 allows you to forward interrupt information to the DP master in a double
word. This information can then be evaluated in the OB40_POINT_ADDR variable in the
OB40. The interrupt information can be programmed user-specific. For a detailed description
of SFC 7 "DP_PRAL", refer to the
System Software for S7-300/400 - System and Standard
Functions
Reference Manual.
Setting user-defined interrupts of Intelligent Slaves using SFB 75
In the CPU 31x-2 operating in DP slave mode, you can trigger user-defined interrupts from
the user program in the DP master. SFB 75 "SALRM" is used to send a process or
diagnostic interrupt from a slot in the transfer area (virtual slot) to the associated DP master
from the user program on an intelligent slave. This starts the associated OB on the DP
master.
Additional interrupt-specific information may be included. You can read this additional
information in the DP master using SFB 54 "RALRM."