Rockwell Automation 2707-NP2 MICROVIEW SOFTWARE PROGRAMMING MANUAL - Manual (Page 24)

Publication 2707-PM002B-EN-P
3-4 Designing Microview Applications
Data Scaling Data entered by an operator can be scaled from engineering units
such as gallons or PSI to machine control values. Likewise, data
displays can take raw numeric values and scale them so they are
displayed in engineering units.
Scaling of data is accomplished by defining a proportional ratio
between the register value range and the display or entry value range.
If a 1:1 ratio exists, the MicroView displayed or entered value equals
the controller register value.
Here is an example of scaling using a data display to scale a register
data range of 0 to 4,095 to a MicroView display range of -100 to +300.
When the ratio between the controller register values and MicroView
display or entry values is not a multiple of 2, the value is rounded.
Rounding may result in a 1 count error. Depending upon the
direction of the scaling, this means that:
When the ratio between the controller register values and MicroView
display or entry values is not a multiple of 2, the value is rounded.
Rounding may result in a 1 count error. Depending upon the
direction of the scaling, this means that:
•
The MicroView display value may be off by 1 when the
controller register value is scaled
•
The controller register value may be off by one when a
MicroView data entry is scaled.
An error screen appears if a rounding error occurs at the end points of
a data range. You must either increase the minimum or decrease the
maximum range of either the controller register or display ranges.
If the Display
Register Contains:
+300
+100
-100
4,095
2,047
0
This Value
is Displayed:
Controller
Register Limits
MicroView
Display Limits
0
4,095
+300
-100
SCALING
SCALING