Profibus DP 59/176
3 842 530 344/2014-05, MIT: ID 40, Bosch Rexroth AG
7.8 Profibus GSD file
The characteristic communication features of the ID 40/SLK is determined in the
form of an electronic device data sheet (GSD file). GSD files for devices with the DP
Communication Profile are outlined in Profibus Guideline No. 2.121.
The general settings in the GSD file include:
• Manufacturer: Bosch Rexroth AG
• Device name: ID 40/SLK-PDP
• Hardware and software release versions,
• supported baud rates [kbps]:
9,6 19,2 93,75 187,5 500 1500 3000 6000 12000
7.8.1 Distribution of SLK module configuration
The slave-specific settings in the GSD file contain information on the available I/O
modules. The cyclical data communication of Profibus supports a payload transport
of 216 bytes. This data area is available for both command-oriented and event-
oriented data exchange. The I/O modules defined in the GSD file represent the
allocation of these bytes to the data exchange channels.
The maximum volume of a command-oriented data exchange is 212 bytes, since at
least 4 bytes always have to be allocated to the event-oriented data exchange. This is
necessary for transmitting the system status, which is always present.
The maximum volume of an event-oriented data exchange is 208 bytes, since at least
8 bytes always have to be allocated to the command-oriented data exchange. Only
then can a configuration command with at least one data byte be sent to the SLK.
7.8.2 Sample I/O module configuration
If there are 121 bytes of user data, the “128 I/O cmd-oriented data acc.” module has
to be used for configuration. This means that a maximum of 121 bytes can be read
from the MDT per command. If more data is desired, it has to be distributed across
multiple read commands.
In the following example, 250 bytes should be read starting at SLK address
0x000001F0. The data block is retrieved through three consecutive read commands.
Each command reads 121 bytes. The byte count of the previous read command is
added to the SLK address of a read command.
Table 19: Distribution of read access to large amounts of data in individual commands
SLK address Byte count
First read command 0x000001F0 121
Second read command 0x00000269 121
Third read command 0x000002E2 8
Individual data packets can now be provided in the PLC program as a single data
block.
PROOF COPY 1 | 20.05.2014 | FOR INTERNAL USE ONLY
ENGLISH
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