Festo CPX-FB38 Electronic Manual page 104

3. Diagnosis
3−14
If all status bits supply a 0−signal, no fault will be registered.
If, in contrast, a status bit supplies a 1 −signal, there is a fault.
If various faults occur simultaneously on various types of
modules, these faults cannot be assigned via the status bits.
In contrast, faults can be uniquely determined via the I/O
diagnostic interface.
Diagnostic information or error messages of the status bits
functions (or I/O diagnostic interface) can be read out using
the handheld unit (CPX−MMI), Festo Maintenance Tool
(CPX−FMT) and via the EtherCAT network.
Please note
Limited availability of diagnosis information
Status bits forwarded over the EtherCAT network, that is,
diagnostic information or error messages of the CPX
terminal, are almost always not displayed in EtherCAT
configuration and programming software, e.g. TwinCAT.
Display of CPX−specific diagnostic information and error
messages in the online mode of the EtherCAT software is
available to a limited extent only by means of the I/O
diagnostic interface.
Use the handheld unit, the Festo Maintenance Tool or your
requirements according to application programs for
detailed diagnostic functions.
Further instructions on the function and content of the status
bits can be found in the CPX system manual (P.BE−CPX−SYS−...)
in the Diagnostics and error handling section.
Festo P.BE−CPX−FB38−EN en 0804NH