Analog Value Conversion: Function Blocks Fb250 And Fb251 - Siemens S5-100U User Manual

Analog Value Processing
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 (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
BG
KNKT
OGR Upper limit of the output
UGR Lower limit of the output
EINZ
XA
FB
BU
UGR
11-22
Explanation Type
Slot number D KF
Channel number
D KY
Channel type
D KF
value
D KF
value
Single scan
Output value Q W
Error bit Q BI
Range violation Q BI
Scaled range
Figure 11-11. Scaling Schematic for FB250
- FB250 -
Assignment
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
-32767 to +32767
-32767 to +32767
I BI 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
Representation of
the analog input
module
User scaled range
OGR
S5-100U
STL
: JU FB 250
NAME : RLG:AI
BG :
KNKT :
OGR :
UGR :
EINZ :
XA :
FB :
BU :
EWA 4NEB 812 6120-02