Siemens SIMATIC Distributed I/O System DP/ASi Link, Manual

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8-7
Distributed I/O System DP/ASi Link
EWA 4NEB 710 6055-02b
8.2.1 Diagnostic Fundamentals in Operations with an IM308C
You can read the DP/ASi link diagnosis, as the ”slave diagnosis”, using func-
tion block IM308C (FB192) into your PLC – for example, SIMATIC S5 with
IM 308 C.
FB IM308C is described in detail in the Distributed I/O System ET 200
manual.
The DP/ASi link informs the DP master, by means of a high-priority trans-
mission of user data, that a diagnosis is available. The DP master then re-
quests the diagnostic message from the DP/ASi link.
You have two options for requesting a diagnosis:
1. Master diagnostics as overview diagnosis and
2. Slave diagnostics as secondary diagnosis.
The master diagnosis includes an overview diagnosis in the first 16 bytes.
From the overview diagnosis, you can determine the DP slaves which have
reported a diagnosis or which cannot be addressed by that DP master.
The overview diagnosis is recommended especially when you are using sev-
eral DP slaves. By using the master diagnosis, you do not have to request the
slave diagnosis from every DP slave you are using.
The slave diagnosis includes all the diagnostic information of a specific
DP slave.
The structure of the slave diagnosis is explained in section 8.2.3.
The method for reading the diagnosis into your PLC is described in detail in
the Distributed I/O System ET 200 manual.
FB IM308C
Exchanging diag-
nostic data
Selecting a diag-
nosis
Master diagnosis
Slave diagnosis
Method
Diagnostics and Error Handling