For measuring ranges exceeding roughly 400 mm and where higher accuracy requirements exist, it generally proves economical to use bridge-type machines equipped with air bearings.

A fixed-bridge construction is optimally suited to machines with transmitted-light illumination. The rigidity of the entire system enables excellent measuring uncertainty values. This is supported by manufacturing the bridge in a single piece with close tolerances. No subsequent adjustment of the guideway components is required.Through appropriate design measures, a constant prestress of the entire guideway system can be attained similar to the machines described above.