Evaluating Diagnostic Data In Step7 - Weidmuller SAI Active Universal Pro Series Manual

Commissioning the PROFIBUS-DP
6.10 Evaluating diagnostic data
in Step7
Whereas the data for inputs and outputs can be ex-
changed and processed directly in Step7 with
PROFIBUS via the input and output image, diagnos-
tic data must be read into the application program
with an SFC.
Diagnostics data (slave diagnostics) of a DP slave is
read with the SFC 13 "DPNRM_DG".
Input variables:
REQ = 1: Request to read
LADDR: Planned diagnostics address of the DP slave; this can be read in the hardware con-
figurator.
Note: The address must be entered in hexadecimal, for example, the diagnostic ad-
dress 1022 (3FEH) means: LADDR: = W#16#3FE.
Output variables:
RET_VAL RET_VAL contains the length of the actual transmitted data.
If an error occurs when the function is being processed, the return value contains an
error code.
RECORD Target range for the read diagnostic data.
The minimum length of the data record to be read or the target range is 51.
BUSY = 1 The read operation has not been completed.
Table 96 Diagnostics function block
The maximum in Byts amounts to 244 which must be read.
In the example above, 51 bytes following the flag byte M 120.0 are reserved as target range of the diagnos-
tics data for an SAI-AU M12 PB 16D. These are divided up as follows:
136
Figure 79 Diagnostics function block
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