Functional description

A sinusoidal voltage is induced in the cos (S1 – S3) and sin (S2 – S4) secondary side when supplying the primary winding Ref1 – Ref2 with a sinusoidal excitation signal.

The strength of the induced voltage depends on the transformation ratio and the angle position of the rotor α. The secondary windings are mechanically offset by 90°.

This results in 2 signals (sine and cosine) that are phase-shifted by 90°. These signals can be interpreted by the encoder evaluation unit in order to calculate an absolute position within a rotor revolution.

The sin and cos signal voltage are calculated according to the following calculation rule:

U_S1-S3 = T_R × U_Ref1-Ref2 × cos (α)

U_S2-S4 = T_R × U_Ref1-Ref2 × sin (α)