another noob trying to tune the servo

PCW
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20 Sep 2018 21:01 #117824 by PCW

Replied by PCW on topic another noob trying to tune the servo

Those changes are necessary but not sufficient...

Looks like you don't have the stepgen enabled

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Psykhon
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20 Sep 2018 21:06 #117825 by Psykhon

Replied by Psykhon on topic another noob trying to tune the servo

there is definitely something odd here, please look the attachment

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PCW
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20 Sep 2018 21:08 #117826 by PCW

Replied by PCW on topic another noob trying to tune the servo

Not really very odd, thats expected if the stepgen is not enabled

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Psykhon
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20 Sep 2018 21:18 #117827 by Psykhon

Replied by Psykhon on topic another noob trying to tune the servo

As allways you are completely right, the problem was that the 7i78 doenst have enable signals, so I had to use one of the 7i77 outputs:
net z-enable <= axis.2.amp-enable-out
net z-enable => hm2_5i25.0.7i77.0.0.output-00

but forgot to:
net z-enable => hm2_5i25.0.stepgen.00.enable

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PCW
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20 Sep 2018 21:40 #117828 by PCW

Replied by PCW on topic another noob trying to tune the servo

Yeah stepgens need to be enabled just like analog outputs

Actually you can use 7I78 step/dir outputs as enables if a 5V signal will do
(just dont enable all the stepgens, and the unused stepgen pins will revert to GPIO pins)

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Psykhon
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21 Sep 2018 14:20 #117849 by Psykhon

Replied by Psykhon on topic another noob trying to tune the servo

Any ideas why the dro's doenst show 0 when homed? it only happens en x & Y where there are servos

They also hunt a little, 1 encoder count as it seems, but I read this may be normal right? Or it can be tuned to be completely steady?

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PCW
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21 Sep 2018 16:21 #117852 by PCW

Replied by PCW on topic another noob trying to tune the servo

Those are static position errors you should be able to remove them by adding some I term. You can often eliminate +-1 count dithering by adding a bit of deadzone.

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andypugh
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26 Sep 2018 12:04 #117998 by andypugh

Replied by andypugh on topic another noob trying to tune the servo

PCW wrote:
Those are static position errors you should be able to remove them by adding some I term. You can often eliminate +-1 count dithering by adding a bit of deadzone.

Or choose to display commanded position instead :-)

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another noob trying to tune the servo

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