8° incidence
7 wavelengths 
0.01% resolution
0.1% accuracy



016 CT7a: Practice your rotation

CT-7a inherits accuracy, stability and repeatability of CT-7.

However the  measurement repeatability and accuracy depends on repeatability of mechanical positioning of the rotating arm while it is manually rotated  between  REFERENCE and MEASUREMENT position.

It is important to check how precisely you operate the rotating arm.

A good habit is to use classical backlash suppression technique: approach the desired position always in the same direction.

CT-7A absolute calibration

We recommend to train operator for the rotation movement of the reference mirror arm by practicing the sequence:

-rotate the reference mirror in the down position with backlash suppression movement;
-perform one REFERENCE measurement (i.e. calibrate to 100%) /REFERENCE command/;
-rotate the reference mirror in the upper position;
-rotate again the reference mirror in the down position;
-perform one measurement while mirror is in the down position /MEASURE command/;

You shall read a result very close to 100,0% - if not, continue the practice!

For your convenience you may work with CT-7a connected to PC-Console using “Calibration/Reference” and “Measure” buttons on the “CT7 Management” panel.

Hint: press “0.00” or “0.000” button to increase the resolution of data transferred to CT7-Console.

Hint: Before practicing, go to “Measure Configuration” panel and select “Reflection” CART - this will speed-up the measurement by skipping the scattering.