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5.3.2
Structure of user data
This means that the telegrams of cyclical data transmission have the basic
structure below:
Protocol frame
(Header)
Figure 1 The basic structure of the Profibus telegrams
The types below have been defined:
n
User data without a text range and with defined setpoint and process data
(white) and as many as 8 additional values that can be selected via ID (grey).
Also refer to Figure 2
n
User data with a text range and with the selection of process data described
above.
Text range (TXT)
You can read or write texts with as many as 128 bytes with the TXT telegram part.
The section on "Text Transmission via Profibus DP" describes the necessary
mechanisms of order/reply identifiers.
We distinguish 4-and 20-byte text blocks where the longer variant should only be
used with greater quantities of text to keep the transmission period low.
Process data range
You can use the process data to transmit control words and setpoints (orders:
master —> 6 controller) or state words and actual values (replies: controller —>
master).
The process data transmitted go into effect immediately.
DISOMAT Opus, Satus, Tersus, Data Communication
© Schenck Process
Texts (TXT)
User data
Optional
Process data
BV-H2359GB/0902
5.3 Profibus DP protocol
Protocol frame
(Trailer)
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