IDL 101
COMMUNICATION
HB_IDL101_E_V222.doc
71
Gantner Instruments Test & Measurement GmbH
LEr
: Length-Repeated (length = 1 byte):
The Length-Repeated LEr corresponds to the specification Length LE. It is stated again in the telegram for data
protection control purposes.
DA
: Destination-Address (length = 1 byte):
The Destination-Address DA identifies the address of the communication 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 appliance and is communicated to the communication
partner with the telegram. Source-Address can assume 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 acknowledgement (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 telegram which contains the data for the communication
partner with the DA address.
ResDataUnit
: Response-Data-Unit (length = 0 ... n byte):
The Response-Data-Unit identifies a data field in the response telegram which contains the data for the calling
communication partner.
FCS
: Frame-Check-Sequence (length = 1 byte):
The Frame-Check-Sequence FCS identifies the check sum of the telegram. In the PROFIBUS-protocol this is the sum of
the ASCII-values from DA to DataUnit
modulo
256:
CheckSum_PROFIBUS = [DA+SA+FC+DataUnit] mod 256.
In the PROFIBUS-protocol the value is stated as a hexadecimal value (
hex
00 .. FF).
ED
: End-Delimiter (length = 1 byte):
The End-Delimiter ED identifies the end of the telegrams. In the PROFIBUS-protocol it has the value
hex
16.
SC
: Short-Acknowledgement-Frame (length = 1 byte):
The Short-Acknowledgement-Frame SC identifies a telegram that can be sent back to the communication partner as an
acknowledgement. With SDA-requests it can be used as a positive receive acknowledgement. With SRD-requests it can
be returned as a negative acknowledgement.
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