Diagnostics
5.1 Reactions to Faults
ET 200S Distributed I/O System - Fail-Safe Modules
42 Installation and Operating Manual, 08/2008, A5E00103686-07
Remedying faults in the F-system
To remedy faults in your F-system, proceed as described in EN 61508-1 Section 7.15.2.4
and EN 61508-2 Section 7.6.2.1 e.
The following steps must be performed:
1. Diagnosis and repair of the fault
2. Revalidation of the safety function
3. Recording in the service report
Fail-safe value output for F-modules
If channels are passivated with F-DI modules, the F-system provides fail-safe values for the
safety program instead of the process values applied to the fail-safe inputs.
● For F-DI modules, this is always the fail-safe value "0".
In the case of F-DO modules and PM-E F pm DC24V PROFIsafe, if passivation occurs 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 de-energized. This also applies
when the F-CPU goes into STOP mode. You cannot program fail-safe values.
Depending on the F-system used and the type of fault that occurred, (F-I/O, channel or
communication fault), fail-safe values are used either for the affected channel only or for all
channels of the fail-safe module involved.
In S7 distributed safety F-systems up to V5.3, the entire F-module is passivated when a
channel fault occurs. Starting with S7 distributed safety V5.4, F-modules as of the indicated
order numbers can also be passivated on a channel-level basis.
Reintegration of a Fail-Safe Module
The system changes from fail-safe to process values (reintegration of an F-module) either
automatically or only after user acknowledgment in the safety program. It may be necessary
to remove and insert the F-module to clear certain channel faults. For an exact list of such
faults, see section
"Power module PM-E F pm DC24V PROFIsafe"
to
"Digital electronic
module4 F-DO DC24V/2A PROFIsafe"
in the "Causes of errors and troubleshooting" tables.
After reintegration, the following occurs:
● For a fail-safe DI module, the process values pending at the fail-safe inputs are provided
for the safety program
● For a fail-safe DO module, the output values provided in the safety program are again
transferred to the fail-safe outputs
Additional Information on Passivation and Reintegration
For further information about fail-safe I/O access refer to the
S7 Distributed Safety,
Configuring and Programming
manual or the
S7 F/FH Systems, Configuring and
Programming
manual.
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