Rockwell Automation 2706-MB1 MESSAGEVIEW 421 SOFTWARE MANUAL - Manual (Page 85)

4–37 Planning an Application
Publication 2706-817
Scaled Data Display Variables take raw numeric values and
mathematically manipulate them so the values can be shown in
standard units such as:
•
gallons
•
feet per second
•
pounds per square inch.
Values from the logic controller address are scaled using the formula:
y = mx + b
y = scaled (displayed) value
m = scale (multiplier)
x = value stored in controller address
b = offset.
The scale and offset values are entered in the Tag Editor.
Example: Scaling a Display Variable
Flow Rate
Transducer
Value
510
Valve #1
Flow Rate
Transducer
510
Controller
13
Scaling
(x 0.0059 + 10)
Note: Messages sent to slave devices may contain scaled variables.
The variable tag contains the scaling information.
Scaling Data Display
Variables