User Manual

SD: Start-Delimiter (length = 1 byte):

The Start-Delimiter SD identifies the beginning of a telegram. It

can assume the following values in the PROFIBUS-protocol:

format

request telegram response telegram data field length

SD1 hex 10 hex 10 0

SD2 hex 68 hex 68 1 ... 246 (32)

SD3 hex A2 hex A2 8

Table 11.11 Start-Delimiter (SD) in the PROFIBUS-protocol

LE: Length (length = 1 byte):

The Length LE identifies the length of the telegram with vari-

able data field length (SD2-telegram) and comprises the char-

acters from DA to DataUnit. Thus it corresponds to the length

of DataUnit+3 and can have values between 4 and 249. In the

PROFIBUS-DP-protocol the length of the data field is generally

limited to 32 bytes. Since the data logger has no telegrams with

a usable data length of more than 32 bytes, the data logger can

also be integrated in bus topologies with DP-protocol.

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.

Hardware Manual COMBILOG 1022

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