Siemens SIMATIC ET 200S Installation And Operating Manual page 40

Diagnostics
5.1 Reactions to Faults
Fail-safe value Output for Fail-Safe Modules
With F-DI modules, if channels are passivated, 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.
With F-DO and PM-E F pm DC24V PROFIsafe 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 go to the zero current and zero voltage
state. This also applies when the F-CPU goes into STOP mode. It is not necessary to assign
parameters for fail-safe values.
Depending on which F-system is 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, when a channel fault occurs the entire
F-module is passivated. 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
Switchover from fail-safe values to process values (reintegration of an F-module) occurs
either automatically or only after user acknowledgement in the safety program. If channel
faults occur, it may be necessary to remove and insert the F-module. For an exact list of the
faults that require removal and insertion of the F-module see
PROFIsafe Power Module"
the "Causes of Faults and Corrective Measures" table.
After reintegration, the following occurs:
• For a fail-safe DI module, the process values pending at the fail-safe inputs are provided
• For a fail-safe DO module, the output values provided in the safety program are again
Additional Information on Passivation and Reintegration
For more detailed information on passivation and reintegration of F-I/O, refer to the
S7 Distributed Safety, Configuring and Programming
Systems
F-DI Module Reaction to Communication Errors
The F-DI module responds differently to a communication error than to other faults.
If a communication fault occurs, the current process values remain set at the inputs of the
F-DI module; there is no passivation of the channels. The current process values are sent to
the F-CPU and are passivated in the F-CPU.
5-2
for the safety program
transferred to the fail-safe outputs
manual.
"4 F-DO DC24V/2A PROFIsafe Digital Electronic Module"
to
Hardware Installation and Operating Manual, 07/2005, A5E00103686-04
"PM-E F pm DC24V
S7 F/FH Automation
manual or
ET 200S Distributed I/O System - Fail-Safe Modules
in