Agilent Technologies 5530, Getting Started Manual

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Chapter 8 Ensuring Repeatability, Accuracy, and Resolution
Ensuring Accuracy
8-6 Getting Started Guide
8
Figure 8-2. Example of Abbé error
To calculate the amount of measurement error resulting from Abbé offset,
use the following formula:
Offset distance
×
tan (offset angle)
For an angle of 20 degrees or less, you can approximate the Abbé error
using the following formula:
Deadpath error
Deadpath is the part of the measurement path that the retroreflector
never moves through. In other words, it is the distance between the
interferometer and the retroreflector when they are closest together (see
Figure 8-3).
*
Measurement axis at
lead screw
**
Measurement axis at
probe or tool path
1
Measurement axis
2
Work piece
3
Abbé offset
4
Error in measurement
5
Measured distance
6
Actual distance
7
Probe or tool path
θ
Angle of offset
2
6
5
1,7
2 3
1
6
5
7
0 0
**
*
4
4
Offset dis ce tan
5
6 –
×
10
arc sec
----------------------
⎝ ⎠
⎜ ⎟
⎛ ⎞
angle in arc onds sec
( ) × ×