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Author Topic: Help with motor tuning xyz profile settings mach3  (Read 415 times)

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Help with motor tuning xyz profile settings mach3
« on: January 19, 2019, 11:18:08 PM »
Hi I am totally lost trying to work out the settings for the motor tuning...hoping someone might be able to help.
I am unable to find/translate the needed information to make the calculations needed to enter the values for the xyz motor tuning profile section.

I have Delta ASD-B2-0721-B 750w servo drives and motors using Taiwan TBI ballscrew transmission.

If anyone has any experience with these or able to provide some help finding and working out the values I would very much appreciate it as I am getting creaking noises on my x axis and high pitch squeels on my y and z axis.

Thanks
Re: Help with motor tuning xyz profile settings mach3
« Reply #1 on: January 20, 2019, 12:48:38 AM »
Hi,
what controller or are you using a parallel port? We need to know the maximum pulse rate your motion control
(be it external OR parallel port) solution can produce.

What pitch is the ballscrew?
Is there a gear or belt reduction between the servo and the ballscrew?

Craig
My wife left with my best friend...
     and I miss him!
Re: Help with motor tuning xyz profile settings mach3
« Reply #2 on: January 20, 2019, 01:45:04 AM »
I have an xhc ethernet controller, 25mm ballscrew.. measures 10mm pitch, each servo is connected directly to the ball screw, I am not sure what in the delta data sheet refers to maximum pulse rate.

here is a link to the pdf

https://www.deltaww.com/Products/PluginWebUserControl/downloadCenterCounter.aspx?DID=3950&DocPath=1&hl=en-US
Re: Help with motor tuning xyz profile settings mach3
« Reply #3 on: January 20, 2019, 01:53:35 AM »
i found it in the controller book i believe it is 2000KHz
Re: Help with motor tuning xyz profile settings mach3
« Reply #4 on: January 20, 2019, 03:26:23 AM »
Hi,
the typical maximum pulse input rate to a step/direction servo drive is 500kHz and that assumes differential signaling.
If you wish to maximize both resolution and speed you need to signal the servo drive with differential line
drivers. Commonly it is an added complication that is over the top and not required. We shall see once we do the
calculations.

I assume the servos are rated to 3000 rpm? If they are hooked directly to 10mm pitch screws then at 3000 rpm the axis would
be moving at 30 m/min.....quite respectable for a production machine and WAY quick for a hobby machine.

Lets assume that rather than signaling at 500kHz we chose a much easier  signaling rate, say 100kHz. This could be done
without line drivers but just simple open collector outputs.

At a step rate of 100kHz that equates to:
pulses per minute = 100,000 X 60
                           =6,000,000
the pulses per rev =6,000,000 /3,000
                           =2000 pulse per revolution.
Linear resolution = 10 (mm pitch) / 2000
                         = 5um   (or 0.0002 inch per step)

Thus if you made choices such that the maximium step pulse rate is 100kHz that would still allow you to spin the servo
at its maximum speed with a steps per revolution of 2000 and with your 10mm pitch screw that works out to 5um
resolution....pretty damned good. You could do better if you wish by either decreasing the maximum speed or attempt to
signal the servo drive faster.

If that sounds good to you I suggest you program the drive to accept 2000 input pulses to cause the servo to complete one revolution.

I presume you have set the servo drive up in Position Mode (Step/Direction)? You can use the Low speed input, it will make it that
much easier. That is parameter P1-00 on page 6-3

You need to confirm that parameter P1-46 is set at its default of 2500. That means the encoder is effectively 2500 lines
and because of quadrature encoding that means 10,000 count per rev.

Now we know what electronic gearing we require, the encoder is 10,000 count per rev whereas we want 2000 input pluses
to cause the servo to revolve once. Thus the ratio is 5:1.

So the Numerator N1 parameter P1-44 page 6-8 should be set to 5000 say and therefore the Denominator M parameter
P1-45 on age 6-8 should be set to 1000.

Now you can set Machs motor tuning parameters. We have set the servo drive up to revolve once with 2000 pulses and the
axis will move 10mm . Thus the steps per unit are 2000 /10 =200. I'm assuming you native units are millimeters.
Your max velocity will be 30,000 mm/min and you could probably set those great big kick-arse servos up for an acceleration of
1000 mm/sec/sec to start with. The servos themselves I'm guessing wont be working at all at that piddling rate. I suspect
unless you have a really big or heavy machine you could take the accel up to 10,000 mm/sec/sec. Your machine is going
to Rock-and-Roll!!!!

Craig
My wife left with my best friend...
     and I miss him!
Re: Help with motor tuning xyz profile settings mach3
« Reply #5 on: January 20, 2019, 03:40:07 AM »
Hi and thanks a lot Craig...please see the attachment for my xhc controller is that the correct max signalling output 2000khz?

Yes rated rpm for motors is 3000rpm

Cheers
Lyndon
« Last Edit: January 20, 2019, 03:53:20 AM by dragon_sa »
Re: Help with motor tuning xyz profile settings mach3
« Reply #6 on: January 20, 2019, 03:55:20 AM »
I edited the last post to include the pic I forgot to add :)
Re: Help with motor tuning xyz profile settings mach3
« Reply #7 on: January 20, 2019, 03:56:04 AM »
Hi,
those Delta servos are really good and a ton of power.

If you don't mind me asking why you spent all that money on really good servos and then buy an XHC controller?

Craig
« Last Edit: January 20, 2019, 04:00:02 AM by joeaverage »
My wife left with my best friend...
     and I miss him!
Re: Help with motor tuning xyz profile settings mach3
« Reply #8 on: January 20, 2019, 04:31:59 AM »
I was going to build the machine myself...then when I priced a few chinese ones with what I thought were the needed upgrades...cost was getting similar then all my time, effort and extra research needed to make it successful...was a better option to get one built from someone with over a decade of experience in manufacturing and some reasonable reviews...I dont really know much about the controllers...except for my little bit of experience with this one...it has been super easy to connect to...but I didnt realise that there were better options for controllers or what would be a good one to get...and I just accepted what they put in not even really knowing which one it was....I spent some time researching to get best value for accuracy and upgraded from the steppers and pully system to a decent gear drive and ball screw setup...i was going to go for Japanese motors but couldnt justify the extra 1200aud for my first machine.
The machine has got lots of little issues that I am solowly resolving but has done some nice stuff on my first few tests

So what would be your recommended figures based on the 2000Khz...do I still check the drivers for those settings you mentioned?

Lyndon

« Last Edit: January 20, 2019, 04:36:17 AM by dragon_sa »
Re: Help with motor tuning xyz profile settings mach3
« Reply #9 on: January 20, 2019, 05:00:59 AM »
Hi,
the figures I talked about in the previous post mean that the controller will only be operating at 100kHz, so the
XHC controller should do that at a canter. The real reason for 'taking it easy' is to reduce the signaling speed between
the controller and the servo drive, ensuring reliable signaling at high speeds can be problematic. If however you
scale your demands for resolution/speed then you can still get a good result and a lowish signaling speed.

The XHC is overall not a bad unit and nicely made. Where a lot of Chinese made controllers perform poorly
the real-time support features.

There are quite a raft of features that have to be done by the controller, the communication loop back to Mach is just
too slow. Things like probing, homing, lathe threading, THC and backlash compensation. I would suggest carry on with
the XHC but if it gives you any grief throw it away.

Peter Homann of Homann Designs in Melbourne sells the Ethernet SmoothStepper by Warp9 TD (US) for about $250 AUD.
It is a little quicker,4Mhz, but its more about those real-time features and about the manfacturers support you get from Warp9,
just light years ahead of XHC. You'd swear China is on another planet when it comes to getting help from them for their
own products.

If you read any of my posts I am pretty scathing of Chinese made controllers. Delta servos are Chinese/Taiwanese
and they are great....I wish I could afford them. They are right in the performance mix with Japanese, US and European
servos but at a very good price. Another brand carving out a good reputation is DMM. Its a Canadian company, all its R&D
and sales support is done in Canada but they manufacture in China. Good quality and performance at a great price.

There are even cheaper Chinese made brands.....but I won't be buying them....Delta, yes to be sure! But I'm staying
away from all the other stuff.

Craig
My wife left with my best friend...
     and I miss him!