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Getting small movements which not supposet to..
« on: May 28, 2013, 01:41:49 AM »
OK below is  a link of my converted cnc lathe:

http://youtu.be/Ws-0u15YJxE

Got some tuning issues here, when I run Gcode from Visual turn, the movement is not 1:1, but when input let say G0X0Z100 @ MDI, the Z axis does move to 100mm.
The DC motor encoders' are 1000 lines.
For X axis: both gears are T22, which is 1:1, so step per = 1000 x 4 (1000 x 4 for quadrature) =4000/rev.
1 rev  = 5mm therefore 1mm = 800.
Currently the X step per = 33 not 800. If I use 800, the X axis would exceed travel limit...

help..

Offline Hood

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Re: Getting small movements which not supposet to..
« Reply #1 on: May 28, 2013, 06:10:09 AM »
What drives are you using? Could there be electronic gearing in the drive so that one pulse sent from Mach could be seen by the drive as X amount?
Hood
Re: Getting small movements which not supposet to..
« Reply #2 on: May 28, 2013, 07:25:21 AM »
Hi Hood,
             I'm using this drive:
http://www.leadshine.com/Product_Show.aspx?ID=79
Ok I thought this drive do not have electronic gear ratio, the stepper driver from Leadshine use dip switches for micro stepping so I thought the DC servo drive might have the same for electronic gear but not.

Offline Hood

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Re: Getting small movements which not supposet to..
« Reply #3 on: May 28, 2013, 07:47:42 AM »
It does according to their specs on the page you linked to, see screenshot.
Hood
Re: Getting small movements which not supposet to..
« Reply #4 on: May 28, 2013, 08:52:56 AM »
Thanks Hood, will do the tuning tomorrow.

Offline Hood

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Re: Getting small movements which not supposet to..
« Reply #5 on: May 28, 2013, 10:50:14 AM »
I had a look and there is a setting in the software for the gearing, you will just be wanting 1:1 likely.
Hood
Re: Getting small movements which not supposet to..
« Reply #6 on: May 29, 2013, 01:15:58 AM »
Sholdn't 1:1 be the default setting?
Installed Pro tuner, but can not connect between the DC servo drive and PC due to bad connection RS232, the PCIe RS232 card from Uptech.
Need to sort this out 1s.
Re: Getting small movements which not supposet to..
« Reply #7 on: May 29, 2013, 02:02:24 AM »
I switch to another PC which has a RS232 on board, got connection between the drive and pc and here is what it looks like:





sorry for the 2 image screen shot, don't know how it happened..
Re: Getting small movements which not supposet to..
« Reply #8 on: May 29, 2013, 02:28:23 AM »


I chaged the value of CAM_numerator: 1 to 8, CAM_denominator:1 to 3 then start....
I'm still suspecting the cause is Visual Turn not the tuning....

Offline Hood

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Re: Getting small movements which not supposet to..
« Reply #9 on: May 29, 2013, 03:56:47 AM »
The setting should be 1 and 1 if wanting un-geared input. Easy way to tell if it is CAM or Drives is command a move via MDI. If you zero the X DRO then command a move such as G0X20 then the X axis should move to that point. I will assume you are set up in Diameter mode so with a X20 move commanded the X axis should move 10mm (I think you are using metric units?) If set in Radius mode then the axis would move 20mm.

Hood