Siemens SIMATIC S5-100U System Manual page 298

Analog Value Processing
The tank contents are determined from the make-up quantity.
STL
L KF +300
L FW 1
-F
T FW 20
...
The UGR and OGR parameters of FB 251 refer to the nominal range of the analog output module.
For this reason, the UGR parameter must be assigned the value -30.0.
- 30.0 m 3
- 20 mA
Figure 11-15. Transformation of the Analog Value to the Nominal Range
STL
...
JU FB251
NAME :RLG:AQ
XE :FW20
BG :1
KNKT :0.1
OGR :300
UGR :-300
FEH :F0.2
BU :F0.3
BE
11-26
Explanation
Maximum tank capacity
Make-up quantity
Calculate difference
Store tank contents in FW20
Tank contents
0.0 m 3
0 mA
Explanation
Unconditional call-up FB251
Tank contents
Slot 1
Channel 0, channel type 1
3
High limit 30.0 m
3
Low limit - 30.0 m
"1", if wire break
"1", if tank too full
S5-100U
30.0 m 3
20 mA
EWA 4NEB 812 6120-02b