Siemens S5-100U - Page 291

S5-100U Analog Value Processing
11.6.2 Output of Analog Value - FB251 -
Analog values can be output to analog output modules using this function block. In doing so, values
from the range between the lower limit (UGR) and high limit (OGR) parameters are converted to the
nominal range of the module in question.
Table 11-18. Call and Parameter Assignments of FB251
Parameter Explanation Type Assignment
BG Slot address D KF 0 to 7
KNKT Channel number
Channel type
D KY KY = x,y
x = 0;1
y = 0;1
0: unipolar repre-
sentation
1: bipolar fixed-point
number
UGR Lower limit of the output
value
D KF -32767 to +32767
FEH Error in limit value
setting
Q BI “1” if UGR = OGR,
invalid channel or slot,
or invalid channel type
BU Input value exceeds
UGR or OGR
Q BI “1” if XE lies outside
limits (UGR; OGR).
XE assumes the limit
value
: JU FB 251
NAME : RLG:AQ
XE :
BG :
KNKT :
OGR :
UGR :
FEH :
BU :
XE Analog value to be
output
I W Input value (two's
complement) in the
range UGR to OGR
OGR Upper limit of the output
value
D KF -32767 to +32767
Example: Display of Tank Contents on an Analog Measuring Instrument
The make-up quantity of a 30 m
3
tank is stored in flag word 1 as a fixed-point number (see example
FB250). The ± 20 mA analog output module in slot 1, channel 0, transfers the standardized value
to the measuring instrument. The value is displayed within the range 0 to 20 mA.
Figure 11-14. Schematic for “Display of Tank Contents”
PS
AQ
CPU
EWA 4NEB 812 6120-02 11-25