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

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Hi Aram,

A couple of things come to mind.
Check your servo amp with 9-10 vdc on the input.... a nine volt  
battery is handy. :-)
The axis should move out smartly,  close to the maximum velocity you  
want.
If it doesn't then adjust the gain on the amp until it does.

After that is verified then go back to tuning emc. IIRC typical P   
values for the Vital card are in the low thousands.
Work toward getting P set at 0.6 times P when the axis just sustains  
oscillation. Leave it there while you work with other parameters.

As for the halscope stuff: try getting on irc ... freenode.net   #emc  
and you should be able to get help.

Dave
On Dec 8, 2006, at 9:30 AM, Kasparov, Aram wrote:

> 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:
>
>  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.
>
> I increased P to 583 (randomly pick that figure) and machine moves  
> very slow no matter how big F feed I put in.
>
> When P is small than machine moves faster indirectly from volume of  
> F feed.
>
>
>
> Am I doing something wrong?
>
>
>
> Thanks
>
> 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
> emc'ers using it as a tuning method; both are engineers. Please note
> the response curves in your reference and the long settling times of
> ZN. OK, maybe for process control but maybe not the best for machine
> control especially with your servo amps and motors which should give
> you really nice performance.
>
> Setup halscope to monitor following error and any other parameters
> you want to keep track of.
>
>   I use only the first step of ZN, i.e. just to set P (gain). The
> instructions I got are slightly different from that listed in your
> reference. For step 1 set I and D to zero then increase P until the
> axis just sustains oscillation and multiply that value by 0.6. This
> is a good starting point for P.
>
> Using MDI with F (velocity) at some high value, half max velocity to
> max velocity command short moves ...
> just enough to reach full velocity adjust FF1 and monitor the results
> in terms of  following error. FF1 will affect the offset of your
> following error and can be adjusted so the following error is
> virtually on zero with small bumps at either end of the travel for
> acceleration and deceleration. When you get the following error as
> small as you can with FF1 go back and vary P a bit to see if you can
> improve the overall result. When you are satisfied with that
> adjustment then try small values for D and I. I've never been very
> successful at finding appropriate I's and D's but that may be machine
> related.
>
> With my Mazak (200 ipm) I get following errors of about 0.015" with
> 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
> 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
>> about how to tune up servomotors.
>>
>> http://www.olympus-controls.com/whitepapers.php <http://kiccvan18/
>> exchweb/bin/redir.asp?URL=http://www.olympus-controls.com/
>> whitepapers.php>
>>
>> I am interesting in how close or useful that information to tune up
>> EMC2 AC servomotors?
>>
>> Thanks
>>
>> aramk
>>
>>
>>
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