Analog Value Conversion: Function Blocks Fb250 And Fb251 - Siemens SIMATIC S5-95F Manual

S5-95F

11.6 Analog Value Conversion: Function Blocks FB250 and FB251

11.6.1 Reading in and Scaling an Analog Value
Function block FB250 reads in an analog value from an analog input module and outputs a value XA
in the scale range specified by the user.
Specify the type of analog value representation for the module (channel type) in the KNKT
parameter.
Define the desired range using the "upper limit" (OGR) and "lower limit" (UGR) parameters.
Table 11-8. Call and Parameter Assignments of FB250
Parameter
BG
KNKT
OGR Upper limit of the output
UGR Lower limit of the output
EINZ
XA
FB
BU
Scaling Schematic
UGR
EWA 4NEB 812 6210-02
Explanation Type
Slot number
Channel number
Channel type
value
value
Not relevant
Output value
Error bit
Range violation
Scaled range
Figure 11-7. Scaling Schematic for FB250
- FB250 -
Assignment
D KF 0 to 7
KY = x,y
D KY
x = 0 to 3
y = 3 to 6
3: Absolute value
representation
(4 to 20 mA)
4: Unipolar represen-
tation
5: Bipolar absolute value
6: Bipolar fixed-point
number
D KF -32767 to +32767
D KF -32767 to +32767
Q W Scaled analog value is "0"
on wirebreak
Q BI "1" on wirebreak, illegal
channel or slot number or
illegal channel type
Q BI "1" when nominal range is
exceeded
OGR
Analog Value Processing
STL
: JU FB 250
NAME : RLG:AI
BG :
KNKT :
OGR :
UGR :
EINZ :
XA :
FB :
BU :
Representation of
the analog input
module
User scaled range
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