| | | The Sensonics R40A Series angular position transducer uses the principle of the Rotary Variable Differential Transformer (RVDT) to convert the rotation of a shaft into a proportional electrical output signal. The RVDT primary winding is energised with AC from an external source and induces in the secondary windings an AC signal, the magnitude and phase of which are determined by the angular position of a specially shaped rotor attached to the operating shaft. Separate external signal conditioning is necessary to produce a DC signal proportional to shaft position. The R40A is housed within a stainless steel case to the format of a size 18 synchro. The 6.35mm dia. x 15.4mm long operating shaft is internally supported by a pair of miniature, precision ball races which permit continuous rotation and minimum friction. The rear face of the unit supports the cable outlet and optional stainless steel flexible armouring to the specified length. Although the transducer is capable of continuous rotation, a plot of angular rotation against magnitude and phase of output signal over 360° would result in one complete sine wave (and therefore two positions, separated by 180° of rotation, where the output signal is zero). To avoid ambiguity, just one of the null positions is chosen during final test and a calibration is made over the most linear range either side of this null. Both the shaft and the case are marked to show the alignment at the null point selected. Individual calibration certificates are provided. | | |