Resolution, repeatability & linearity will be as specified, provided gap is within 1.10+/-0.35mm. Within limits, the IncOder’s measurement resolution and repeatability are independent of air gap. If the air-gap tolerance is increased from ±0.35mm to ±0.50mm the quoted measurement non-linearity will double. For example, if a 250mm IncOder has an air-gap tolerance of ±0.50mm the quoted linearity will increase from +/-40 arc-seconds to +/-80 arc-seconds.
If the quoted linearity is required then the specified air-gap tolerance should be maintained. This is most easily achieved using the Set Screw Rotor whose axial position can be readily set. Preferably the Rotor’s inner diameter should be a close fit to the through shaft. Alternatively the required gap may be maintained by the use of a shim. Peelable shims are available as an IncOder accessory.