Product Description:

Okuma manufactures the ER-JH-7200D encoder for its Absolute Encoders series. The unit is housed in a shafted casing and is shipped with an attached cable, so installation does not require separate connector work. As an absolute position sensor, it delivers a unique numeric word for every mechanical angle, allowing a CNC or motion controller to recover true position immediately after power-up and eliminating the need for homing routines in servo-driven axes.

The encoder’s timing core runs at 81.92 MHz. Within each 0.1 mechanical revolution, the disk generates 16384 per 0.1 rev clock pulses, providing fine angular segmentation before the resolver interpolates them. Stator windings are energized with 5 kHz sine/cosine excitation, producing a continuous analog profile that the signal processor digitizes for smoother interpolation. Position data is transmitted to the drive over a serial feedback link, reducing conductor count through the cable and simplifying noise shielding. The least significant numerical increment equals 0.0001 mechanical revolutions, so the controller can command very small movements without relying on estimation. Mechanical attachment is intended for a servo motor shaft, and a rotor step of one electrical position per full phase rotation helps keep incremental error low.

Long-range referencing is handled through a programmed output shaft cycle of 7200 rev. After that count is reached, the absolute word sequence repeats, supporting multi-turn tracking in large rotary tables. Coil phasing is arranged so each resolver phase shift covers 36°, a value that balances signal amplitude with electrical isolation. The sensing element is a multi-pole resolver, allowing high pole density without excessive diameter growth. For the upper digits, the encoder relies on pulse type heads that add whole-turn information on top of the fine-angle code and complete the absolute feedback chain.