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Table Of Contents
SFCs for Diagnostics
System Software for S7-300/400 System and Standard Functions - Volume 1/2
13-24
A5E00709327-01
Operating method
SFC 103 "DP_TOPOL" operates asynchronously, that is, its execution requires
several SFC calls. Call SFC 103 with REQ = 1 to initiate identification of the DP
bus topology and call SFC 103 with R=1 to abort the process.
The job status is indicated at the output parameters RET_VAL and BUSY, see also
Meaning of the Parameters REQ, RET_VAL and BUSY with Asynchronous SFCs.
Note
It may take several minutes to identify the topology.
Job Identification
Input parameter DP_ID determines a request.
When you call SFC 103 "DP_TOPOL" once again before the identification of the
topology has been completed, the further response of the SFC depends on
whether or not the new request is identical to the previous: If parameter DP_ID
corresponds with a job that has not yet been completed, the SFC call is interpreted
as part of a call sequence and the value W#16#7002 will be entered in RET_VAL.
If this is a new job, however, the CPU will reject it.
Parameter Declaration Data -
type
Memory area Description
REQ INPUT BOOL I, Q, M, D, L,
constant
REQ=1: Initiate identification of the bus
topology
R INPUT BOOL I, Q, M, D, L,
constant
R=1: Abort topology identification
DP_ID INPUT INT I, Q, M, D, L,
constant
DP master system ID of the DP master
system whose topology is to be identified
RET_VAL OUTPUT INT I, Q, M, D, L The return value will contain an error code if
an error occurs while the function is being
processed.
BUSY OUTPUT BOOL I, Q, M, D, L BUSY=1: Bus topology identification is still
busy.
DPR OUTPUT BYTE I, Q, M, D, L PROFIBUS address of the diagnostic repeater
that has generated the error message
DPRI OUTPUT BYTE I, Q, M, D, L Measurement segment of the diagnostic
repeater that has generated the error
message:
•
Bit 0 = 1: Error on segment DP2
•
Bit 1 = 1: Error on segment DP3
•
Bit 4 = 1: Temporary disruptions at
segment DP3
•
Bit 5 = 1: Permanent disruptions at
segment DP3
Permanent errors:
The system has detected permanent network errors which prevent successful
identification of the topology. You can fetch the diagnostic information via SFC 13 "DPNRM_DG" or
STEP 7 in order to view the details.
Temporary errors:
The system has detected temporary network errors which prevent successful
identification of the topology. This may be due to a bad contact or a recurring error. The nature of these
disruptions does not allow a precise location of the error source.