[Bdi4emc-help] RE: Bdi4emc-help Digest, Vol 5, Issue 2

[Paul]

Hi Craig

On Tuesday 04 April 2006 05:20, Craigg Gadd wrote:
> Thanks for the help.  The motherboard is an Intel N440BX, it does have an
> onboard video card which I think is a Cirrus 4680?  The processor is 600Mhz
> P3 and I have 256Mb of ram  

The 440BX chipset is probably the best one you could ever want for realtime 
control, and it is likely that the video has a separate 2Meg of static RAM.. 
Check the BIOS for a Legacy USB option and disable it along with any power 
management "features".

> I increased the period to .00005 and was able to run the default
> generic.ini file, so I was quite pleased with the progress.  When I set the
> period back to .000022 I froze again so that appears to be the problem.

With a similar system (Celeron 433MHz, 440BX chipset), I have run freqmod at 
20uSec and quickstep down to 5uSec - This was done purely for a "what if" 
exercise and is not recommended as jitter severely affects the stability of 
the stepper pulse train.

> One thing I thought was interesting is that I had installed a vital systems
> servo card (the 4-Axis version) and using the vital.ini, I was able to run
> with the period set to .000022 without any problems.  I guess this has
> something to do with the way the card is managing certain processes that
> would normally be handled by the motherboard?  

If you are using a Vital (or any other servo interface card), the period 
*should* be ignored by the driver. I will look at the relevant sections of 
the code and see if there is a problem there..

> Anyway,I'm off to hook up some motors to see if I can make something move.
> I'll report back.

With the Vital card, I would suggest setting PERIOD to 0.00005 or 0.0001 and 
ensure the servo and trajectory cycle times are a multiple of the base 
period.


Regards, Paul.