First thanks for the fast answer.
"Everything you are doing looks correct. You don't show the HAL lines, but I
assume that you are connecting the A and B phases of the
encoder as well."
Of course. Just tried to keep the story in limits.
" Does it turn off again when the index pulse arrives?"
Yes clearly visible on the scope.
"Does it turn off again when the index pulse arrives?"
Yes both of them go to zero and they start to count again as the axis
travels to previous position.
" Does that mean you are running a stepper machine with encoders?"
Yes. The machine still have manual handles and the encoder/DRO is practical
for manual position checking.
"If so, are you taking the position feedback from the stepgen module or
from the encoder module? "
Stepgen only, never had luck with the encoder FB, regardless how big was the
following error always got FE message. In fact I get following error on the
first 0.005mm or so. (The ball screw is metric and has 0.03mm backlash
because of the timing belt.)
"I think that could give the result you are seeing."
It is clear now, however I see no reason, why stepgen can't check a flag/bit
for encoder Z status and zero the position target and FB, during homing.
Wasting only few processor cycles, when timing is not a real issue at low
search speed and this would have a lot of benefits in fact that is the way
it should work to meet with the documentation. Checked the stepgen C code
and see no reason why an additional flag check would not be feasible. When
index-enable is not on just skip the "settozero" subroutine. Maybe a future
feature?
" If you are sending the position command to a PID loop"
PID is what I wanted to avoid. Chapter 14 section 1 says stepgen has a
pre-tuned internal position loop when in fact this is not entirely correct
term (or maybe I do not use the "pre-tuned loop" term properly). Would be
better to say stepgen "makes itself happy" ;-) regardless of the actual
position or say stepgen has a fixed preset position loop without any error
correction to make it very clear.
"EMC is happy, but it has no idea that you have an encoder and cannot use
the encoder data for homing."
Understand, but consider to put it into stepgen, otherwise the entire
documentation is misleading or not fully clear as it never states that
switch+index homing is only working in PID mode. Or someone should change
the docs or add a remark.(I am not complaining in fact I appreciate that you
guys are spending your free time here.)
Anyway I am going back and try to change the config to PID.
Thanks,
Y.
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