Rockwell Automation 1746-XXXX SLC 500 4-Channel Analog I/O Modules User Manual - Manual (Page 64)

Publication 1746-UM005B-EN-P - June 2004
6-2 Programming Examples
The scaling operation is displayed in the following graph. It displays
the linear relationship between the input and the resulting scaled
values.
Calculating the Linear Relationship
Use the following equations to express the linear relationship between
the input value and the resulting scaled value.
Scaled value = (input value x slope) + offset
Slope = (scaled max. - scaled min.) / (input max. - input min.)
(500 - 100) / (32,767 - 0) = 400/32,767
Offset = scaled min. - (input min. x slope)
100 - (0 x (400/32,767)) = 100
Scaled value = (input value x (400 / 32767)) + 100
Scaled
Value
0=0V dc
(input min.)
Low
Limit
High
Limit 32767 = 10V dc – 1 LSB
(input max.)
Process operating range
500
°
C
100
°
C
300
°
C
275
°
C
(Scaled max.)
(Scaled min.)
Input Value