HP 5528A

Model 5528A
Appendi x B: Measurement Considerat ion s
B-2
Squarene ss and parallelism of travel between two axes characterize how any two axes are
positioned
relative to each other . Both measurements are accomplished by performing two
Straightness measurement s. ( See Figure B- 2. )
Y AXIS
~ 1\ I
,-~ ~t-=:!::: :::;;:==t> Z AXIS
1'\ \
\ XAXI8
Figure 8-2. Squarencss Between Axes
Each of the se characteristics contributes to po sitioning ac curacy and precision at any point within
the machine's work zone.
All of these measurements (exc ept roll ) ca n be made with the Laser Measurement System.
REPEATABILITY, ACCURACY, RESOLUTION
It is impo rtant that you under stand the definitions of " r epeatability", " accuracy", and
"reso luti on"; th ese are co mmon terms in industry, and are u se d throughout this U se r 's Guide.
THESE TERMS ARE NOT INTERCHANGEAB LE.
REP EAT ABILITY is the range among a group of meas urement s at a larget p os ition.
A
ss ume that a mark sman is s hooting at a target. The tightness of his shot pallern is a measure of his
repeatability, using that gun, in that enviro nm ent. ( See Fi gure 8-3.)
ACCURACY __ /'
V"- REPEATA.,LlTY
RESOLUTION
Figure 8 -3. Target Examples of Ac cur ac y, Precision, and Resolulion