Checkline PT-RTR - Manual (Page 14)

11
This is the default measurement mode. Linearize mode is ON
when this box is ticked and the "H
L
" appears on the display.
An undesirable characteristic of replica tape is that measurements
made with analog spring micrometers are most accurate near the
middle of each grade's range and least accurate at the outer ends
of each grade's range. That is why two other grades, Coarse
Minus and X-Coarse Plus, are used to check and, if necessary,
adjust measurements at the lower and upper ends of the primary
range of 20 - 115 µm (0.8 - 4.5 mils).
Inside the primary range, the upper end of Coarse grade’s range
and the lower end of X-Coarse grade’s range share a 38 - 64 μm
(1.5 - 2.5 mil) "overlap" region. Current Testex instructions
describe a relatively complicated and time consuming procedure
(the average of one reading using Coarse grade and one reading
using X-Coarse grade) that is used to knit the Coarse and
X-Coarse sub-ranges together to achieve reasonably accurate
readings over the primary range. This method is a compromise
between accuracy and ease of use.
When the Linearize box is NOT ticked, the PosiTector RTR
displays a height value of H comparable to the value an analog
spring micrometer would display after the 50.8 μm (2 mil) of
incompressible polyester substrate has been subtracted. In other
words, it is the average of the maximum peak-to-valley distances
obtained by measuring the thickness of the replica tape without
any correction.
When the Linearize box IS ticked, the PosiTector RTR displays
a more accurate peak-to-valley height measurement H
L
that has
been adjusted for the non-linearity of replica tape. There is no
need to average 2 or more replicas from different grades of tape
AND there is no need to subtract the 50.8 μm (2 mil) of
incompressible polyester substrate. Ensure the proper tape grade,
C or XC, has been selected (pg. 10) and appears in the upper left
corner of the display.
Linearize