Theodor Friedrichs COMBILOG 1020, Hardware Manual

Page: 122 / 170

Hardware Manual COMBILOG 1020
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DA: Destination-Address (length = 1 byte):
The Destination-Address DA identifies the address of the com-
munication partner to whom the data shall be transmitted or from
whom data shall be requested. Destination-Address can have
values from 0 to 127 in the PROFIBUS-protocol. It is stated here
as a hexadecimal value (hex 00 .. 7F).
SA: Source-Address (length = 1 byte):
The Source-Address SA identifies the address of your own appli-
ance and is reported to the communication partner with the tele-
gram. Source-Address can have values from 0 to 127 (
hex 00 ..
7F).
FC: Frame-Control (length = 1 byte):
The Frame-Control FC identifies the type of telegram (request or
response telegram), the type of station (passive or active station),
the type of data transmission (send and/or request data, with or
without acknowledgement, etc.) and the telegram acknowledge-
ment (successful transmission or unsuccessful transmission). For
the entire listing, coding and meaning of the Frame-Control see
the PROFIBUS-Norm DIN 19245, part 1.
ReqDataUnit: Request-Data-Unit (length = 0 ... n byte):
The Request-Data-Unit identifies a data field in the request tele-
gram which contains the data for the communication partner with
the DA address.