In order to supply more clear data regarding the accuracy of the machine, Tomelleri decided to use the ISO 10360-2 norm, valid for traditional three-dimensional machines and which supplies the maximum error in the measuring field.

The width of the maximum error that is calculated on a single point, is measured by carrying out over 105 measurements required by the norm and another 850 measurements in order to understand the variety of the measuring conditions of the arms.

The maximum error value gives no subjective data. Tomelleri, however, declares also the 2 sigma value which depends on the distribution of the measurements.

Using the certified gauge and the sphere it is possible at any moment, to carry out the accuracy certificate of the machine with a print out of the document which certifies:
The maximum error in the measuring field
The 2 sigma value in the measuring field
The maximum repeatability error on the sphere