spindle-index-enable

cgc
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11 years 2 weeks ago - 11 years 2 weeks ago #63823 by cgc

Replied by cgc on topic spindle-index-enable

Ah, OK !
in normal mode, the postion go to zero erery spindle turn if the index pulse is true.
In synchronized mode "motion" prevent this with the spindle-index-enable signal and start sync motion if the index is true, seen by the index-enable go false.

OK, thank you, that was the information, that I need.

Last edit: 11 years 2 weeks ago by cgc.

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andypugh
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11 years 2 weeks ago #63824 by andypugh

Replied by andypugh on topic spindle-index-enable

cgc wrote: Ah, OK !
in normal mode, the postion go to zero erery spindle turn if the index pulse is true.
In synchronized mode "motion" prevent this with the spindle-index-enable signal and start sync motion if the index is true, seen by the index-enable is false.

Not exactly.

In normal mode the encoder counts without limit.
at the beginning of a spindle synchronised movement the encoder is zeroed to index once, then counts without limit.

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cgc
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11 years 5 days ago - 11 years 5 days ago #64338 by cgc

Replied by cgc on topic spindle-index-enable

It is running

Lathe spindle with servo drive and syncron motion, without external encoder.

I configure the servodrive for a value of 1.000 for each spindle turn. The decimal place increase from 0.000 to 0.999 and go back to 0.000. This is the trigger to generate the index signal.

Frank

Code:

component servospindle "lathe spindle with servomotor and synchron motion";

//---------------------------------------------------------------

pin io  bit index_enable "index enable from/to motion";
pin out bit index "generated index pulse";
pin in  float servopos "position servomotor";
pin out float spindlepos "position spindle";
variable float new_decimal_place;
variable float old_decimal_place;
variable float diff_decimal_place;
variable int offset = 0;

//---------------------------------------------------------------

function _;
license "GPL";

;;

FUNCTION(_)
{
int turns = (int)servopos;

	new_decimal_place = servopos - turns;

	diff_decimal_place = new_decimal_place - old_decimal_place;

	if ((diff_decimal_place > 0.7) || (diff_decimal_place < -0.7))
		index = 1;
	else
		index = 0;

	if(index_enable && index)
	{
		offset = turns;
		index_enable = 0;
	}		 

	spindlepos = servopos - offset;

	old_decimal_place = new_decimal_place;
}

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Last edit: 11 years 5 days ago by cgc.

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cncbasher
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11 years 5 days ago #64341 by cncbasher

Replied by cncbasher on topic spindle-index-enable

could you get it to count the index's then you could use it say on a rotary table and turn the exact revs back to zero
or for argument turn the spindle 20 times and then back etc ..

very useful depending on how accurate you can get it counting ,i would have thought

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cgc
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11 years 5 days ago #64343 by cgc

Replied by cgc on topic spindle-index-enable

Yes, it has a jitter, depend on spindle speed and speed of servo thread.
More speed of servo-thread and lower spindle speed will be better.
You should note nyquist-shannon.
But, I think, the encoder-index solution has also a jitter.

regards Frank

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