Allen-Bradley SLC 500 Series User Manual

Publication 1747-RM001G-EN-P - November 2008
Math Instructions 4-17
Application Example 1 - Converting 4 to 20 mA Analog Input
Signal to PID Process Variable
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 Rate) + Offset
Rate = (Scaled MAX. - Scaled MIN.) / (Input MAX. - Input MIN.)
(16,383 - 0)/(16,384 - 3277) = 1.249 (or 12,490/10000)
Offset = Scaled MIN. - (Input MIN. X Rate)
0 - (3277 x 1.249) = -4093
16,383
(Scaled MAX.)
Scaled Value
0
(Scaled MIN.)
3,277
(Input MIN.)
Input Value
16,384
(Input MAX.)

Allen-Bradley SLC 500 Series Specifications

General

Brand	Allen-Bradley
Model	SLC 500 Series
Category	Controller
Language	English