Siemens SIMATIC S7 F Manual page 103

Programming
In both cases, the necessary F module drivers and module diagnostic blocks are
automatically inserted into separate CFC charts called @F1, @F2, ... and
interconnected. The instances of the F module drivers automatically receive the
name you have entered in HWCONFIG for the associated F-I/O (F_Name_x). See
the chapter entitled "Parameterization of the F-I/Os".
Placing and Interconnecting the F Module Drivers Manually
Proceed as follows:
1. Insert the appropriate F module driver in any F chart for each configured Fail-
safe signal module. Only one F module driver is required for the two modules
when Fail-safe signal modules are in a redundant configuration.
2. For each F channel driver, interconnect the CHADDR I/O with the
corresponding CHADDRxx I/O of the F module driver, as shown in the
examples above. Make sure that the channel number xx of the CHADDRxx I/O
corresponds to the channel number of the F channel driver.
3. Allocate the logical start address of the Fail-safe signal module to the LADDR
I/O for each F module driver. In the case of redundant modules, allocate the
logical start address of the second module to the LADDR_R I/O in addition.
We recommend that you use the same instance name for the F-module as you
used in HWCONFIG for the associated F-I/O (F_Name_x). See the chapter
entitled "Parameterization of the F-I/Os".
Simulation Mode
For each input channel, you can specify a simulation value instead of the current
one received from the F-I/O. At an output, a simulation value can also be output
instead of the value at input I (e.g. for hardware tests). To output simulation values
on a channel, proceed as follows:
1. Activate the output of simulation values by interconnecting the SIM_ON input
with a constant 1 or a signal.
2. Interconnect the SIM_I input for F_CH_DI or F_CH_DO and SIM_V for
F_CH_AI with the desired signal, or parameterize it with the desired value.
Substitute Values
If the F-I/O or an F-driver block detects an error, substitute values are output from
the F-driver or from the F-I/O. In the case of digital input and digital output drivers,
the substitute value 0 is output, and the output QBAD=1 is set. In the case of
analog input drivers, depending on the parameter assignment, the substitute value
SUBS_V or the last valid value is output, and the output QBAD=1 is set (see the
description of F_CH_AI).
Fail-Safe Systems
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