Siemens S5-100U - Analog Value Conversion: Function Blocks FB250 and FB251

Analog Value Processing S5-100U
11.6 Analog Value Conversion: Function Blocks FB250 and FB251
11.6.1 Reading in and Scaling an Analog Value - FB250 -
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 (see Table 11-17). Define the desired range using the “upper limit” (OGR) and "lower
limit” (UGR) parameters.
Table 11-17. Call and Parameter Assignments of FB250
Parameter Explanation Type
BG Slot number D KF
KNKT Channel number
Channel type
D KY
0 to 7
KY = x,y
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
OGR Upper limit of the output
value
D KF
UGR Lower limit of the output
value
D KF
EINZ Single scan I BI
XA Output value Q W
FB Error bit Q BI
BU Range violation Q BI
-32767 to +32767
-32767 to +32767
Not relevant
Scaled analog value is “0”
on wirebreak
“1” on wirebreak, illegal
channel or slot number or
illegal channel type
“1” when nominal range is
exceeded
Assignment
: JU FB 250
NAME : RLG:AI
BG :
KNKT :
OGR :
UGR :
EINZ :
XA :
FB :
BU :
STL
Figure 11-11. Scaling Schematic for FB250
UGR
Representation of
the analog input
module
User scaled range
OGR
Scaled range
11-22 EWA 4NEB 812 6120-02