Festo — CPX-AP-A — 2022-07
System communication and address assignment
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System communication and address assignment
The internal system communication is at the level of the interlinking modules.
The addresses of the modules are assigned automatically every time the automation system is
started. In this example, the interface is given the address 1 or 4.
2
3
1
2
3
1
1
1
Fig. 13: System communication and addressing
1
Connection for system communication
[XF20]
2
Interface
3
Connection for system communication
[XF10]
Loss of function due to incorrectly connected or non-approved connecting cables.
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Always attach the connecting cables for the modules to the connection [XF10].
–
Always attach the forwarding of the connecting cables to the connection [XF20].
–
Only use approved connecting cables from the Festo catalogue
Behaviour in the event of incorrect configuration after restart
When establishing a connection with the higher-order controller, the configuration is checked for the
following criteria, depending on the network protocol of the interface:
–
Total number of input bytes and output bytes
–
Module codes and sequence of modules
–
Length and format of the start-up parameterisation
If there are deviations, the connection to the higher-order controller is rejected and a network-specific
error message is generated.
Behaviour when changing the configuration during operation
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If a module is removed during operation, process data are not transferred to the higher-order
controller for this module and all downstream modules. The failure of the module is signalled via a
diagnostics message and, if necessary, network-specific status bytes in the process data.
–
If an additional module is added after the connection is established with the higher-order controller
or an existing module is replaced, this module is not included in the active configuration and data
exchange with this module is not possible.
The system must be restarted for changes to the configuration to become active.
