The following relationship exists between the eccentricity 3. Error due to radial deviation of the bearing The equation for the measuring error Ï• is also valid for radial deviation of the bearing if the value e is replaced with the eccentric- ity value, i.e. half of the radial deviation (half of the displayed value).Bearing compliance to radial shaft loading causes similar errors.

Rotary encoders with Inductive Scanning

e , the mean graduation di-ameter D and the measuring error Ï• (see illustration below): 4. Position error within one signal period For rotary encoders without integrated bearing with inductive scanning, the attainable accuracy depends on the power supply, the temperature, the rotational speed, the working gap between the rotor and stator, and on the mounting conditions. The system accuracy stated in the Specifi cations takes all these factors of infl uence into account, as long as the permissible operating parameters and mounting tolerances are maintained. Measuring error Ï• Ï• = ± 412 · Ï• = Measuring error in ” (angular seconds)e = Eccentricity of the radial grating to the bearing in µmD = Mean graduation diameter in mmModelMean graduation diameter DError per 1 µm of eccentricity
u The scanning units of all HEIDENHAIN en-coders are adjusted so that without any further electrical adjustment being neces- sary while mounting, the maximum posi- tion error values within one signal period will not exceed the values listed below.ModelLine countPosition error within one signal period Ï• D = 24.85 mm± 16.5" ± 8.0" ± 2.7" ERO 1420ERO 1470 ERO 1480 ± 19.0" ± 6.5" ± 26.0" ± 8.7" ERO 1225ERO 1285 D = 38.5 mm± 10.7" ± 38.0" ± 13.0" ± 40.0" ± 14.0"
u ± 76.0" ± 25.0"The values for the position errors within one signal period are already included in the system accuracy. Larger errors can occur if the mounting tolerances are exceeded. ERO 1324ERO 1384 D = 60.5 mm± 6.8" eD TTL1 V
PP ERO 50002048 1500 1024 1000 512 Ï• as a function of the mean graduation diameter D and the eccentricity e M Center of graduation Ï• “True” angle Ï• ‘ Scanned angle Scanning unit

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