Diagnostics
5.1 Reactions to Faults
ET 200pro Distributed I/O System - Fail-Safe Modules
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Operating Instructions, 05/2007, A5E00394073-02
Fail-Safe Value Output for Fail-Safe Modules
In the case of F-DI modules, if channels are passivated, the F-system provides fail-safe
values for the safety program instead of the process data pending at the fail-safe inputs:
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For F-DI modules, this is always the fail-safe value (0).
In the case of F-DO modules, if channels are passivated, the F-system transfers fail-safe
values (0) to the fail-safe outputs instead of the output values provided by the safety
program. The output channels are set to the zero current and zero voltage state. This also
applies when the F-CPU switches to STOP mode. It is not possible to assign fail-safe values.
Depending on which F-system you are using and the type of fault that occurred (F-I/O fault,
channel fault or communication error), fail-safe values are used either for the relevant
channel only or for all channels of the relevant fail-safe module.
In
S7 Distributed Safety F-systems up to V 5.3, when a channel fault occurs the entire F-
module is passivated (in
S7 Distributed Safety V 5.4 and higher, the entire module or,
alternatively, selected channel(s) are passivated).
Reintegration of a Fail-Safe Module
Switchover from fail-safe values to process data (reintegration of an F-module) occurs
automatically or, alternatively, after user acknowledgment in the safety program. If channel
faults occur, it may be necessary to remove and reinsert the F-module. A detailed listing of
faults requiring removal and insertion of the F-module can be found in
●
the "Diagnostic Messages of 4/8 F-DI/4 F-DO DC24V/2A PROFIsafe Electronic Module,
Causes of Faults and Corrective Actions" tables for
"8/16 F-DI DC24V PROFIsafe" to "4/8
F-DI/4 F-DO DC24V/2A PROFIsafe"
●
the "Diagnostic Messages of F-Switch PROFIsafe Electronic Module, Causes of Faults
and Corrective Actions" tables for
"F-Switch PROFIsafe".
After reintegration:
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In the case of a fail-safe DI module, the process data pending at the fail-safe inputs are
provided to the safety program
●
In the case of a fail-safe DO module, the output values provided in the safety program are
again transferred to the fail-safe outputs
Additional Information About Passivation and Reintegration
For additional information about passivation and reintegration of F-I/O, refer to the
S7 Distributed Safety, Configuring and Programming manual.
Behavior of the F-DI Module When a Communication Error Occurs
The F-DI module responds differently to a communication error than to other faults or errors.
If a communication error occurs, the current process data remain set at the inputs of the F-DI
module; the channels are not passivated. The current process data are sent to the F-CPU
and are passivated there.
