> I said it once already but I don't think everyone caught it: 
> on a spindle encoder used for threading and tapping, it 
> doesn't matter the slightest bit if you miss the index sometimes.  
> 
> You certainly must not stretch it longer than one count, 
> whatever you do.  You would make the cure worse than the problem.
> 
> Chris
> 

OK, it seems reasonable that EMC only needs to reliably sync 
to the index pulse once. If it is able to read the regular encoder
pulses, then it will continue to know the true location even if
future index pulses are missed. Of course any setup that can
reliably read the encoder pulses is also likely to be able to read 
a one count wide index pulse.

Requiring an index pulse that is only one encoder pulse wide
is not reasonable as some types of encoders will not furnish
such a signal. In my opinion the interface and/or polling software
should detect the leading edge of the index pulse as an event
and rely on that.

Regards,
Steve Stallings


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