Chapter 2  Linear Measurements
Aligning the Laser Beam to the Machine’s Travel Path for Short-Range 
Measurements
Measurements Reference Guide 2-25
Aligning the Laser Beam to the Machine’s 
Travel Path for Short-Range Measurements
Use this procedure if your measurement distance is less than 350 mm 
(14 inches). Before proceeding, make sure the machine is at the start 
position and the small aperture is in position over the upper port on the 
laser head. To align the laser beam to the machine’s travel path, follow 
these steps:
1 Place a reference mirror or a similar reflecting device between the 
interferometer and retroreflector.
2 Make sure the reflecting device you use:
• is aligned so its reflecting surface is perpendicular to the machine’s 
travel path, and
• reflects the beam parallel to the machine’s travel path back to the 
upper port on the laser head.
If you use a reference mirror and the machine has T slots, you can align 
the reference mirror so it is parallel to the T slots.
3 Tilt the laser head up or down and rotate it left or right until the return 
beam from the reference mirror forms a halo around the aperture in the 
upper port.
You are now ready to make the linear measurement.