Rockwell Automation 9301 Series RSView32 Users Guide - Manual (Page 95)

Creating tags
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4–15
Scale and Offset
Type a number. For the scale, do not use 0. To disable the scale,
type 1. To disable the offset, type 0.
The scale and offset modify the “raw data” that comes from and
goes to the programmable controller before it is saved in the value
table. The scale and offset also modify the value specified in
RSView32 before it is written to the programmable controller. The
scale is a multiplication factor—the value from the PLC is
multiplied by the scale. The offset is a fixed value—after the value
from the PLC is multiplied by the scale, the offset amount is
added. This formula shows the relationship between the PLC value
and the amount stored in the RSView32 value table:
RSView32 value = (PLC value  scale) + offset
Units
Type a text label, for display only, up to 20 characters long. This
specifies how the tag value is measured (for example, gallon, PSI,
min, sec).
Values from the programmable controller are first scaled, then
added to the offset. When a value is written to the
programmable controller, the process is reversed: the offset is
subtracted and the scale is used for division. This ensures that
the correct, unchanged value is sent to the programmable
controller.
IMPORTANT