Siemens SIMATIC Distributed I/O System DP/ASi Link Manual page 94

Diagnostics and Error Handling
Example At this point you will find a brief example of how to read the slave diagnosis
into your PLC using FB IM308C.
The following assumptions apply to this STEP 5 program:
AWL
:A DB 30
:SPA FB 192
Name :IM308C
DPAD : KH F800
IMST : KY 0, 3
FCT : KC SD
GCGR : KM 0
TYP : KY 0, 20
STAD : KF +1
LENG : KF 26
ERR : DW 0
Diagnostic status
The DP/ASi link can send two different diagnostic messages:
Fault remedied
If there is no longer a reason for a diagnosis, the DP/ASi link sends a final
diagnostic message without any further error messages.
8-8
The IM 308-C is assigned, as a PROFIBUS-DP master, pages 0 to 15
(number 0 of IM 308-C).
The station number of the DP/ASi link is 3.
The slave diagnosis is to be stored in DB 30. You may also use any other
data block to store it in.
The slave diagnosis consists of 26 bytes.
Explanation
Default address area of the IM 308-C
IM No. = 0, DP/ASi link No. = 3
Function: Read slave diagnosis
Not evaluated
S5 data area: DB 20
Diagnostic data, from data word 1 on-
ward
Length of diagnosis = 26 bytes
Error code stored in DW 0 of DB 30
Dynamic diagnostics
If a new fault occurs on the DP/ASi link, the diagnosis is fetched auto-
matically by the DP master.
This procedure is repeated every time the diagnosis is modified.
Static diagnostics
The DP/ASi link uses static diagnostics when the ASi power fails. While
static diagnosis is enabled, the DP master requests diagnostic messages
from the DP/ASi link.
Neither input nor output data are exchanged between the DP master and
the DP/ASi link during this period.
Static diagnostics is retained until you have remedied the reason for the
failure for the diagnostic message.
Distributed I/O System DP/ASi Link
EWA 4NEB 710 6055-02b