Siemens SIMATIC S7 F, Manual

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Fail-Safe Blocks
Fail-Safe Systems
8-16
A5E00085588-03
8.2.3 F_CH_AI
Function
The block reads the analog non-linearized value of the input channel whose
symbolic name is linked to the input VALUE from the associated F module driver
(F_M_AIx). The F module driver has read the non-linearized value via a safety
frame from the analog input module (or possibly a module that is redundant to this
one). The connection to the associated F module driver (F_M_AIx) is automatically
established by means of the interconnection at the input CHADDR.
If the non-linearized value is valid, it is adapted to its physical size and made
available at the output V as a process value.
If the non-linearized value is invalid, a substitute value or the last valid value is
output at the output V, depending on the parameterization. For the reintegration of
a process value after an error is corrected, a user acknowledgment is required
depending on the parameterization and error type.
Alternatively, a simulation value can be output at the output V.
For the process value at the output V, a value status (quality code) is generated at
the output QUALITY that can take on the following states:
State Quality Code
Valid value 16#80
Simulation value 16#60
Substitute value 16#48
Last valid value 16#44
I/Os
Name Data Type Explanation Default
Inputs: ADDR_CODE DWORD Address code for VALUE
interconnection Supplied
automatically
CHADDR F_WORD Address of the channel in the F
module driver Interconnected
automatically
VALUE WORD Must be interconnected with the
symbolic address of the channel
from HWCONFIG across the
margin of the chart 0
VHRANGE F_REAL Upper limit of the process value 0.0
VLRANGE F_REAL Lower limit of the process value 0.0
CH_F_ON F_BOOL 1=activate limit-value monitoring 0
CH_F_HL F_REAL Overrange limit of the input value
(mA) 0.0
CH_F_LL F_REAL Underrange limit of the input value
(mA) 0.0
SIM_V F_REAL Simulation value 0.0