How will the deviations in straightness be recorded?
In most cases, a straightness reference device (e.g. polished Zerodur rule) is placed beside the positioning system and the horizontal measurement probe is driven with the carriage of the positioning system.
The rise of the profile logged is compensated with a compensation line. The deviation in straightness is half of the peak value of the measured, compensated profile. The real profile can deviate from the ideal in both negative and positive directions. Installation location and load changes can have an influence on the amount of deviation in straightness.