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How to calculate max velocity Mesa card can handle

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31 May 2020 23:26 #169589 by Marcodi
How to calculate max velocity Mesa card can handle was created by Marcodi
I have a more technical question.

My setup
Mesa 6i25 card + 7i85s
1000w servo 5 motors in total on machine
Reducer is 8:1
Steplen is 5000

I know there is a way to calculate max velocity on each motor but I don't know how anymore.

Hope someone remembers the formula

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31 May 2020 23:41 #169593 by PCW
Replied by PCW on topic How to calculate max velocity Mesa card can handle
The maximum velocity of a step/dir system would be

1E9*Lead_Screw_pitch / (reduction*steps_per_turn*(StepLen+Stepspace))

Velocity is distance per second
steplen and stepspace are in nanoseconds

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31 May 2020 23:42 #169594 by tommylight
Replied by tommylight on topic How to calculate max velocity Mesa card can handle
1 sec / 5000 nanosec
or
1sec / 5 microsec
or
1 sec / 0.005milisec
or
1 sec / 0.000005 sec
=200000
divide that by two as there is usually the same time for the step space, you would get 100000 pulses per second,
Since there is no info on the encoder, can not help any further.

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01 Jun 2020 00:08 - 01 Jun 2020 00:11 #169596 by Marcodi
Replied by Marcodi on topic How to calculate max velocity Mesa card can handle
What information do you need extra? Which encoder the driver of the motors? Driver is leadshine EL5-D1000. I attached screenshot of specs

.

My system is rack and pinion only the z axis is lead screw.

Is this total pulses that I need to devide by number of Stepgens or is this capable pulses per stepgen
Attachments:
Last edit: 01 Jun 2020 00:11 by Marcodi.

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01 Jun 2020 00:18 #169597 by PCW
Replied by PCW on topic How to calculate max velocity Mesa card can handle
Each stepgen is independent so the number of axis doesn't matter

Those drives will take up to 500 KHz pulse rates so you can go much shorter than
5000 ns pulse width

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01 Jun 2020 00:25 - 01 Jun 2020 00:36 #169598 by Marcodi
Replied by Marcodi on topic How to calculate max velocity Mesa card can handle
I looked in my ini files. Actually steplen is set at 2500 and stepscale is set to 500.

Stepscale means 500 pulses for 1mm of lineair motion correct?

Hope this helps to calculate max velocity and that I understand it again.

Could my steplen be set lower than this?
Last edit: 01 Jun 2020 00:36 by Marcodi.

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01 Jun 2020 00:59 #169601 by PCW
Replied by PCW on topic How to calculate max velocity Mesa card can handle
Yes, if you have a stepscale of 500 pulses per mm and 2500/2500 steplength/stepspace
(200 KHz max) the maximum speed would be 400 mm/s (if not limited by maximum motor RPM lead-screw whip or other limits)

Typically you would set the axis limits to a bit less (25% is standard) than the stepgen limits

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01 Jun 2020 10:21 #169641 by Marcodi
Replied by Marcodi on topic How to calculate max velocity Mesa card can handle
Thank you very much for your help in calculating. I think I understand now.

One more question though based on those specs can the steplen be lowered below 2500.

And how can you see this in the specs what steplen should be?

Regards,

Stephane

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01 Jun 2020 13:48 #169668 by PCW
Replied by PCW on topic How to calculate max velocity Mesa card can handle
The minimum steplength and stepspace for that drive are 1000 ns, though you
should in general not use minimum values but add some margin.

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15 Sep 2021 14:18 - 15 Sep 2021 14:30 #220699 by Clive S
Replied by Clive S on topic How to calculate max velocity Mesa card can handle
 

PCW post=169593 userid=481 The maximum velocity of a step/dir system would be1E9*Lead_Screw_pitch / (reduction*steps_per_turn*(StepLen Stepspace))Velocity is distance per secondsteplen and stepspace are in nanoseconds 


Sorry for resurrecting an old thread but: Re the above regarding the steps per turn just for clarification is the steps_per_turn the screw or the motor shaft?

Does this look correct in the attachment.
Attachments:
Last edit: 15 Sep 2021 14:30 by Clive S.

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