Absolute encoder: Motion axis subcode :082 is often set incorrectly, as a result the position reconstruction does not work and the reference is lost

Question:
Why is the reference lost (HomePosAvailable = False) after switching on the mains, despite using an absolute encoder, if a small value and not zero is set under AxisRef subcode 082?
 
Answer:
The function of the parameter (subcode 082) is in many cases misunderstood by users, as has been shown in practice . Often very small values are set under subcode 082 based on the false assumption that this would increase the accuracy of the reconstructed actual position --> this is not the case !

The accuracy of the actual position reconstructed after power-on depends not depends on the setting under subcode 082. 
The implemented reconstruction procedure ensures a high accuracy independent of 082 . Even if the motor shaft has been moved in a switched-off state. The only condition is that the motor shaft is not moved further than half the display range of the absolute encoder used when switched off. 
A Movement of the motor shaft when switched off state beyond half the display range of the absolute encoder used, cannot be detected!

Function subcode 082:
About subcode 082 the range of permissible movement when switched off can be narrowed down if this should be necessary for the application itself . If the position tolerance set under 082 is exceeded, the reference is reset as a reaction and referencing must be carried out again.

Recommendation:
  • AxisRef subcode 082 = 0 (default) leave set or
  • Set AxisRef Subcode 082 to a larger value so that the reference is not reset even by the smallest changes in position.

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URL for linking this AKB article: https://www.lenze.com/en-de/go/akb/202100199/1/
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