Siemens S5-100U User Manual page 283

Analog Value Processing
If you want to read in the analog value with function block FB250 (analog value reading), you have to
pre-process the analog value before calling up FB250.
Example 1:
Analog input module 466-8MC11 is inserted in slot 1, which means that the module's start address
is 72.
The analog values are stored in four consecutive bytes:
1st analog value (channel 0)
2nd analog value (channel 1)
3rd analog value (channel 2)
4th analog value (channel 3)
Function block FB72, pictured below, reads in the analog values and pre-processes them for
function block FB250 (analog value reading).
FB72
NAME :READ 466
0005 :
0006 :L IW
0007 :T FW
0008 :L IW
0009 :T FW
000A :
000B :L FY
000C :SLW
000D :T IW
000E :
000F :L FY
0010 :SLW
0011 :T IW
0012 :
0013 :L FY
0014 :SLW
0015 :T IW
0016 :
0017 :L FY
0018 :SLW
0019 :T IW
001A :
001B :BE
EWA 4NEB 812 6120-02
in IB72
in IB73
in IB74
in IB75
72
72
74
74
72
3
72
73
3
74
74
3
76
75
3
78
Explanation
READ IN ALL CHANNELS
OF AI 466
READ ALL FOUR CHANNELS
AND REARRANGE
PROCESS EACH ANALOG VALUE
AND REWRITE THEM IN
THE PII SO THAT FB250
CAN ACCESS THEM
WITHIN THAT SCAN.
S5-100U
11-17