The CHS (Calibrated Head System) electronics enables the installer to calibrate the encoded motion of the axis to deliver a high accuracy signal direct to the control. A Calibration Unit (WKE) that includes an additional read head sensor is temporarily placed at 180° from the permanent read head sensor and the axis is rotated 360° after encountering the Reference Index. With this simple procedure, the CHS electronics will eliminate all errors from repeating eccentricity and reduce the error of the grating ring by 50%. For higher accuracy the Calibration Unit can be temporarily placed at 90° and 270° relative to the permanent read head sensor followed by a single rotation at each location after encountering the Reference Index resulting in a 75% reduction of grating ring error. After calibration, the CHS electronics permanently stores the error map and will recall it after power-up and sufficient motion to cross the Reference Index.

The CHS electronics will work with any size grating ring (WMR) or flange (WMF). It requires a single Reference Index mark and the ability for 360° rotation at the time of calibration. The Reference Index mark must be accessible at power-up.

Placement of the AMO grating ring (WMR) or flange (WMF) directly on the rotating shaft has the potential to reduce the axial length of the motion system. Installing the grating ring (WMR) or flange (WMF) at/on/near the bearing reduces mechanical errors resulting from for example torsional wind-up and material deflections. Since the AMO encoder operates without a mechanical coupling and is non-contact it can operate at high speeds without life limitations and there is no backlash.

The AMO encoders are IP-67 rated and insensitive to contaminants like grease, oil, coolant, frost and dirt. This makes placement of the encoder near the bearing, as recommended above, worry free.

The stainless steel grating ring can be furnished for diameters as small as 60mm and there is no limitation on the maximum diameter possible. The AMO inductive angular encoders, with or without the CHS electronics make possible direct encoding of large diameters for high accuracy and improved servo performance. The are used extensively on rotary tables, trunnion tables, torque motors, spindles, multi-axis spindle heads and 4th/5th axis servo controlled machine tools.