F_1Oo2_R - Siemens SIMATIC S7 F Manual

Fail-Safe Blocks
Error Information in Diagnostic Buffer
Error Code (W#16#...)
0x75D9
0x75DA
8.8.4

F_1oo2_R

Function
This block selects its output from one of two inputs based on the QBAD inputs.
IN1 will be output unless QBAD1 is set, which selects IN2 as the output. The
QBAD output will be set if both QBAD inputs are set.
Note
This function block is supplied as a block type. This adds one restriction to the
usage of this block: It may not be placed within another block type.
I/Os
Name
Inputs:
IN1
IN2
QBAD1
QBAD2
DELTA
Outputs: OUT
QBAD
DIS1
DIS2
The block employs a one-out-of-two selection scheme and is often used to detect
the failure of sensors and input processing subsystems. Typical use of this block
would have the V and QBAD outputs of two F_CH_AI blocks connected to the
F_1oo2_R's respective IN and QBAD inputs.
At least one of the two inputs must have their QBAD input clear for QBAD output to
be clear.
The DIS outputs indicate a discrepancy between the respective input, the DELTA
input and the selected output (the difference between IN and OUT is greater than
DELTA).
8-98
Description
Invalid REAL number
Error in the safety data format (error due to online modification of the
Safety Program or internal CPU fault)
Data Type Explanation
F_REAL Input variable 1
F_REAL Input variable 2
F_BOOL IN1 invalid
F_BOOL IN2 invalid
REAL Allowable difference
F_REAL Selected value
BOOL Invalid selected value
BOOL IN1 DELTA Discrepancy
BOOL IN2 DELTA Discrepancy
Default
0.0
0.0
0
0
0.0
0.0
0
0
0
Fail-Safe Systems
A5E00085588-03