Siemens S7-300 Installation And Operating Manual page 313

Note
Note the following regarding diagnostics data:
If a HART channel fault is set, you receive additional information if you read in the status
component (= HART status bytes) in the HART reply data record for the corresponding client
or the diagnostics data record for the corresponding channel with SFC 59.
Fail-safe signal modules
Installation and Operating Manual, 01/2010, A5E00085586-10
Diagnostics data of the signal modules
A.2 Structure and Content of Diagnostic Data
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