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How do you configure encoders with index marks that have a variable delta?

Most incremental encoders have index marks that are uniformly distributed such that adjacent marks are spaced a fixed number of encoder counts apart.  However, some encoders have index marks that occur after a variable number of encoder counts.  Typically, this is found on linear scales where the distance between adjacent marks increases by a fixed amount.  This allows the axis to move a short distance and determine its absolute position.

The servo code normally expects index marks to be repeated by the amount specified in the "Encoder counts used for resolution calc" (DataID 10203).  If index marks are either not found when expected or are found when not expected, an encoder index error will be signaled since this may indicate that the axis is losing or gaining encoder counts.

If your encoder has index marks that have a variable delta, you can configure them by doing one of the following:

Option #1:  Disable index error reporting by setting bit 0 in the "Encoder software configuration" (DataID 10200) to 1.

Option #2:  Enable index error reporting by setting bit 0 in the "Encoder software configuration" (DataID 10200) to 0.  Set the "Encoder counts used for resolution calc" (DataID 10203) to the minimum counts per index.  Set "Index increment for variable index encoder" (DataID 10223) to the index mark increment.  For example, if the encoder's minimum index delta is 8000 counts and it increments by 500 counts per index, then DataID 10203 should be set to 8000 and DataID 10223 should be set to 500.