For applications that require the highest angular accuracy, the REXM angle encoder offers better than ±1 arc second total installed accuracy, zero coupling losses and exceptional repeatability.
Like the RESM, the REXM stainless steel ring has graduations marked directly onto the periphery. However, it features a thicker cross-section designed to minimise all installation errors except eccentricity.
The remaining eccentricity is easily corrected using the combined output of two readheads. Renishaw’s new DSi (Dual Signum Interface) blends the output of two readheads while providing a repeatable and customer programmable reference mark propoZ position. Once the DSi has eliminated eccentricity, the only other errors remaining are graduation and cyclic error (sub-divisional error - SDE) both of which are exceedingly small.
When REXM is used with the DSi, it is possible to achieve a total installed accuracy of better than ±1 arc second. Tests on a 183 mm REXM ring have achieved an impressive total installed accuracy of ± 0.22 arc seconds.
