Rockwell Automation 1746-FIO4V SLC 500 Fast Analog I/O/ User Manual - Manual (Page 54)

Publication 1746-UM009B-EN-P - September 2007
54 Write Ladder Logic
Example Program for Any SLC Processor
Using the scaling instruction (SCL) requires less ladder logic. The SCL
instruction uses the same multiply, divide, and add algorithm but it
does so with a single rate instead of using scaled range and input
range values. The rate is determined by this formula.
] [
GREATER THAN
Source A
Source B
I:1.0
2047
Rung 2:0
Set in-range bit
Rung 2:1
Check for below range
Rung 2:2
Check for above range
Multiply by the
scaled range
Clear fault bit
from overflow
Add offset
B3/0
(U)
S2:5/0
(U)
LES
GRT
MUL
DDV
ADD
LESS THAN
Source A
Source B
I:1.0
409
MULTIPLY
Source A
Source B
Dest
I:1.0
3276
N7:0
DOUBLE DIVIDE
Source A
Dest
1638
N7:0
ADD
Source A
Source B
Dest
N7:0
–818
N7:0
B3/0
(L)
MOV
MOVE
Source
Dest 0
N7:0
B3/0
B3/0
(U)
MOV
MOVE
Source A
Dest 3276
N7:0
Rung 2:3
Scale the analog input
Divide result
by input range
Rung 2:5
Rung 2:4
Move value to output channel 0
END
MOV
MOVE
Source A
Dest N7:0
0:1.0