HP 5528A User Manual

Model 55281\
Di stance Measurements
6-14
Checking Alignment for Cosine Error
NOTE
1. The following t ech nique is th e only way to te ll how large your
cosine error
is. This information is imporlant in helping
you determine the final accuracy of your laser Measure~
ment System. (See "W HAT AfFEC TS ACCURACY" and the
" ERROR BUDGET WORKSHEET". near th e e nd of th is User's
Guide Sec
ti on .)
2. You should always use this technique to check how well yo ur
sys t em is al igned, whether you have used the Gunsight,
Auloreflection,
or Ove rl app in g Dots alignment method .
1. Remove the Optics' targets, if you used them. Make sure that the exit port's s mallapenure is
selected,
lind the return po rt 's larget is in place.
2. Observe two dots on the laser Head' s relUrn port target. The dots may be overlapped
com pl etely ( thu s a pp ea ring as a single dot ).
3. Move the machine you are measuring over its fu ll length of travel.
4.
Observe how much motion occ urs betw een th e I wa dots. Note th at it's the ch~n8e in spacing
between the dOIS , nOI the original spacing between the m. th at's im portant. One dot should
not move.
depending on which Optic is stationary. If there is any motion, cosine error Is
present. (Sec Figure 6 ~ 8 .)
0
0
--I
0
...2..
=-
0
= ~
I
J
r- S & THE DISTANCE THE DOTS MOVE
WHILE MOVING ONE OPTIC ALONG
THE MEASUREMENT AXIS,
Figure 6~8. Visual indi cation of Cosine Error

HP 5528A Specifications

General

Brand	HP
Model	5528A
Category	Measuring Instruments
Language	English