Special field bus features when setting up the field
bus modules
Profibus DP
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Item No.: 099-008225-EWM01
9.1.3
Example of a connection assignment
In the example above, 12 bytes of connection 1 are assigned and configured as “Polled”.
9.2 Profibus
DP
The Profibus node is integrated into the field bus using a GSD file. Here the data is structured in the form
of modules which can have different lengths.
It is advisable to distribute the modules according to the logical block size of the data. For example, word
capacity for nominal and actual values or by bytes for data with byte capacity.
9.2.1
The watchdog
Each DP node can be monitored using a watchdog to secure the data traffic.
It is essential that this function is activated as otherwise the targeted shut-down of the system will no
longer function in the event of an interruption to the field bus master.
9.2.2
DP features
Using watchdog monitoring, the system can be shut down in the event of interruption. In this process, all
I/Os are set to 0 and “FASTSTOP” is detected on the system.
The restart behaviour of the slave when restoring the connection can be configured in the DP features.
Caution is required with the following configuration:
Feature Setting
Re-start behaviour of the node
Automatic re-start
Response from the master
None
If the error that has occurred is reset on an operating panel before the field bus is re-started, the welding
process can be re-started if the start is still present.
Always ensure in an error situation of this type that all outputs of the node have been reset in the
application.
