Re: [Emc-users] Tune-upn AC servomotor

[Kasparov, A. <Ara...@ky...>]

Hi Dave.

I am trying to see any wave type graph on oscilloscope but I can't.

I star machine with very slow motion f0.01 in order to have enough time =
to start oscilloscope, load them up as it described in manual.

I loaded signals:=20

 sig Xpos-cmd     (position command)
sig Xpos-fb      (position feedback)
pin pid.0.error  (position error)
sig Xoutput      (PID loop output)

I only can see one yellow line and two read ones.

If I reduce P to 20.0 then I can't see yellow line at all.=20

I increased P to 583 (randomly pick that figure) and machine moves very =
slow no matter how big F feed I put in.=20

When P is small than machine moves faster indirectly from volume of F =
feed.  =20

=20

Am I doing something wrong?=20

=20

Thanks=20

aramk


________________________________

From: emc...@li... on behalf of Dave Engvall
Sent: Wed 12/6/2006 9:09 AM
To: Enhanced Machine Controller (EMC)
Subject: Re: [Emc-users] Tune-upn AC servomotor



Hi Aram,

ZN tuning has been around for a long time (1943). I know of two=20
emc'ers using it as a tuning method; both are engineers. Please note=20
the response curves in your reference and the long settling times of=20
ZN. OK, maybe for process control but maybe not the best for machine=20
control especially with your servo amps and motors which should give=20
you really nice performance.

Setup halscope to monitor following error and any other parameters=20
you want to keep track of.

  I use only the first step of ZN, i.e. just to set P (gain). The=20
instructions I got are slightly different from that listed in your=20
reference. For step 1 set I and D to zero then increase P until the=20
axis just sustains oscillation and multiply that value by 0.6. This=20
is a good starting point for P.

Using MDI with F (velocity) at some high value, half max velocity to=20
max velocity command short moves ...
just enough to reach full velocity adjust FF1 and monitor the results=20
in terms of  following error. FF1 will affect the offset of your=20
following error and can be adjusted so the following error is=20
virtually on zero with small bumps at either end of the travel for=20
acceleration and deceleration. When you get the following error as=20
small as you can with FF1 go back and vary P a bit to see if you can=20
improve the overall result. When you are satisfied with that=20
adjustment then try small values for D and I. I've never been very=20
successful at finding appropriate I's and D's but that may be machine=20
related.

With my Mazak (200 ipm) I get following errors of about 0.015" with=20
just P. Using FF1 brings this down to 0.0002" to 0.0005".
Attempts to adjust FF0, I and D gets me no closer so I leave them at=20
zero.

Not quite on subject but interesting reading is:

http://www.sunist.org/shared%20documents/TRANSISTOR,%20IC,%20CIRCUIT%
20...%20DATASHEETS/speed%20control%20DC%20motor%20using%20dsp.pdf

Hope this helps and good luck tuning.

Dave


On Dec 6, 2006, at 3:13 AM, Kasparov, Aram wrote:

>
>
> ________________________________
>
>
> Hi
>
> I found that local servo control shop has a web page information=20
> about how to tune up servomotors.
>
> http://www.olympus-controls.com/whitepapers.php <http://kiccvan18/=20
> exchweb/bin/redir.asp?URL=3Dhttp://www.olympus-controls.com/
> whitepapers.php>
>
> I am interesting in how close or useful that information to tune up=20
> EMC2 AC servomotors?
>
> Thanks
>
> aramk
>
>
>
> <winmail.dat>
> ----------------------------------------------------------------------
> ---
> Take Surveys. Earn Cash. Influence the Future of IT
> Join SourceForge.net's Techsay panel and you'll get the chance to=20
> share your
> opinions on IT & business topics through brief surveys - and earn cash
> http://www.techsay.com/default.php?
> =
page=3Djoin.php&p=3Dsourceforge&CID=3DDEVDEV_____________________________=
___
> _______________
> Emc-users mailing list
> Emc...@li...
> https://lists.sourceforge.net/lists/listinfo/emc-users


-------------------------------------------------------------------------=

Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share =
your
opinions on IT & business topics through brief surveys - and earn cash
http://www.techsay.com/default.php?page=3Djoin.php&p=3Dsourceforge&CID=3D=
DEVDEV
_______________________________________________
Emc-users mailing list
Emc...@li...
https://lists.sourceforge.net/lists/listinfo/emc-users