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Longs-Motor - Nema 23, 34, 42, Step Time/space/dir

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26 Sep 2013 10:05 - 26 Sep 2013 10:09 #39201 by fannlow
Hi there,
I have gotten from Longs-Motor on some helpful WAVE-diagram to help setup stepConf wiz.

Step Time
Step Space
Dir. Hold
Dir. Setup

unfortunately, I do not know how to use these for setup, so if anyone has ideas on converting the time, please update for us all to share =)
and perhaps put it on the wiki, so new users will not have to go through all these just to get their machine setup for use.

for driver board DM542A: (my config)

sw1, sw2, sw3, = OFF, OFF, OFF (PEAK 4.20A, RMS 3.00A)
sw 4 = OFF (using full RMS 3.00A)
sw5, sw6, sw7, sw8 = OFF, ON, ON, OFF (using 2,000 pulse/rev or steps/rev)

microstep = 2 (I think this is software microstep on the PC, so feel free to test any numbers, check-in with the base jitters limits on your PC)
leadscrew pitch = 7mm/rev (I use the 1mm/s velocity @ 200mm/s accel. to calculate distance traveled per 1 complete leadscrew rev.)
since I use direct motor to leadscrew, the motor : lead = 1:1

hope these helps,
but still need more input for NEMA 23, 34, 42 (Step Time/Space, Dir. Hold/Setup) timings.
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Last edit: 26 Sep 2013 10:09 by fannlow.

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26 Sep 2013 14:51 - 26 Sep 2013 14:59 #39203 by cncbasher
these are generic drivers sold under many names such as leadshine for example
steplen & stepspace 3500
dirsetup & dirhold 5000
is a good mid point as these have opto isolated inputs

as sw 5, 6 ,7,8 give you 2000 steps per rev this converts to ( 400 steps = 2 or 1/2 step ( minimum for these drives as they do not do full step ) , 800 steps = 4 or 1/4 step )
driver microstepping for this in stepconf is 10
or directly set stepscale in ini file to the number of steps per mm i.e ( 2000 steps per rev / leadscrew pitch ) 2000/7 = 285.714285714
Last edit: 26 Sep 2013 14:59 by cncbasher.
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27 Sep 2013 02:04 #39236 by fannlow
I have tried to reply to this post with images... but unable to post...
is this due to image size 1.7mb @ 5 images? = 8.5mb?

i downloaded pixresizer to resize and try again...

I am attaching my morning tests for this run, and will attach evening tests tomorrow.

hope to shed some light as to what went wrong, and how I can overcome my mistakes and not make them again :)

appreciate any kind help.

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27 Sep 2013 03:02 #39239 by cncbasher
change motor steps from 800 to 200
stepconf takes into account the motor steps and the driver multiplier in it's calculations

leadscrew pitch to 7 as you say your leadscrews give you 7mm per rev

what are you using for leadscrews ? threaded rod ? what size , ballscrews ?

and your problem is ?
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27 Sep 2013 17:10 #39263 by fannlow
1. I am unsure if the distance travel by the nut in 1 rev of screw is the leadpitch linuxcnc needed.
2. When I entered 7mm of leadpitch and test 700mm of +/- area, it runs short of 700mm...maybe ard 635mm.

3. I have changed the
stepTime from 3000ns to 5050ns,
StepSpace from 3000ns to 5050ns,
Dir. Hold is 5000ns,
Dir. Setup is 5000ns.

Data from DM542A driver board wave timing diagram.

4. Still not getting results that tally to 7mm/rev @ 700mm +/- tests.

Any ideas whatvwent wrong?
Velocity is 25mm/s @ accel 150mm/s2
Motor Steps is 200 per rev
Micro step is 4
The same is set on the driver DM542A board 800pulse/rev
DIP @ 5, 7, 8 = ON
DIP @ 1, 2, 3, 4, 6 = OFF

Any help?

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28 Sep 2013 00:15 #39279 by fannlow
this is the evening tests in images...

slightly closer to 7mm per rev now...
but not getting to 7mm accuracy for 700mm tests, IF 7mm is used...

so i used the one in the images...
X & Z axis is a little closer, to the per/rev travel.

since X & Z uses the same type of 17mm dia screw, i get around 2.3mm per rev.
but like the Y axis, I used the one I had in these images to get the test accuracy.

would like to know what went wrong and how I can correct it, so the next time I start another machine, I can resolve these differences =)

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28 Sep 2013 01:56 #39283 by andypugh

When I entered 7mm of leadpitch and test 700mm of +/- area, it runs short of 700mm...maybe ard 635mm.


That seems to show that the leadscrew pitch is exactly 4 threads per inch (6.35mm pitch).
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28 Sep 2013 15:23 - 28 Sep 2013 15:32 #39302 by cncbasher
As Andy says , it looks as if your using Imperial size ballscrews and not Metric , so the calculation required changing to suit hence 6.35mm (1/4")tpi

as a note , you can directly go into the INI file and change the Scale value for that axis manualy to give the same result , all stepconf does is produce values based on calculations and places them in your config file
it is good practice in Linuxcnc to use stepconf to produce a start point, and then manualy edit the files Hal and INI thereafter . you will learn a lot more in the process .
Last edit: 28 Sep 2013 15:32 by cncbasher.
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13 Mar 2015 02:50 #56765 by johnl2


as sw 5, 6 ,7,8 give you 2000 steps per rev this converts to ( 400 steps = 2 or 1/2 step ( minimum for these drives as they do not do full step ) , 800 steps = 4 or 1/4 step )
driver microstepping for this in stepconf is 10


CNCBASHER, I was reading this post and would like to understand what you mean. I thought I just had this all figured out until I read that you said "driver microstepping for this in stepconf is 10". I thought for microstepping in stepconf if you wanted 800 steps, or quarter stepping, you would input 4, no? I am a bit confused. I have 4 in mine and my drivers set to 4. Is this wrong for quarter stepping?

Thanks in advance,

John

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