right! could add it by a toothed wheel and then add the encoder to it. As encoder Lenord+Bauer or a Sensor of VS-Sensorik (located in Germany). Then L+B offers also a small test device to adjust the values correctly. The run-out of the toothed wheel should be adjusted lower then 5µm. The toothed wheel is also available at L+B with mostly 256 tooth.