Appendix C: Communications via PROFIBUS
C.10 Diagnostics
SITRANS LR250 (PROFIBUS PA)
272
Operating Instructions, 08/2014, A5E32221386-AC
C.10
Diagnostics
All diagnostic information shown below is viewable via PDM.
C.10.1
Diagnosis reply (available cyclically)
During DPV0 data exchange, the PROFIBUS PA slave will notify the Master when a serious
error occurs. The Master will then send a Diagnosis request. The reply to this request is normally
logged in the PLC and is referred to as the "Hex values."
The reply may contain two parts. The first part is 6 bytes long and is defined by the PROFIBUS
standard. If there is a second part, it is called the ’extended cyclic diagnosis’ and it is 8 bytes
long. The last 4 bytes of the extended diagnostic message give the error diagnosis [see
Extended Mode Diagnosis (Page 273) and Condensed Mode Diagnosis (Page 274)].
The same information is also available acyclically via the Diagnosis Object.
C.10.2
Diagnosis object (available cyclically or acyclically)
This consists of four bytes.
In PROFIBUS PA there are two options for the Diagnosis Object:
●
Extended Mode Diagnosis (Page 273)
●
Condensed Mode Diagnosis (Page 274)
You can choose which of these will be returned, by enabling or disabling Condensed Status.
See Enable (3.4.1.). When Condensed Status is disabled Extended Mode Diagnosis will be
returned, and the following codes will be used.