Re: Why is the push to such high step rates (Grex and Arc100)?

Thanks for piping in Patrick.

I can understand the desire for a smooth pulse stream and certainly
can appreciate the effects of a bad pulse stream on steppers, but
does that have any effect with servo driven systems?

Also, do you know of any applications that would use such a high
frequency for the pulse stream? I am obsessing about that
specification - sorry.

I just think about the industrial CNC machines I am familiar with
(which also transcends into robotics). 4000 IPM at .0001"
resolution is the fastest I have seen and that was on a FANUC ROBO
Drill machine (basically a 3 axis machining center for drilling).
At 4000 IPM and .0001" resolution, works out to about 660,000 SPS.
It's just mind boggling to watch something move that fast.

Chris

>
> It is not only a matter of how high a pulse rate a device can

produce.

> It is also how much jitter the pulse train has. While a PC may be

able

> to reach 45KHZ. The pusle train can have severe jitter if you try

to

> go just a bit higher and that causes difficulty in building systems
> that push the PC's limits and run in production environments even

at

> bellow 100KHZ.
>
> Having a stable pulse train allows running the same

motor/driver/load

> combo at higher pulse frequencies without missed steps or stalls

in

> long production runs. That also applies to hobby use if you make a
> part that takes days of machine use like it often happens when

using

> software such as DeskProto for example.
>
> That is where products such as te ARCNC100 come in. And once you

have

> solved the jitter issue, it doesn't cost any more to make it go up

to

> 4 MHZ or even 20 MHZ for that matter. Any solution that solves the
> jitter issue involves hardware and for hardware, 4 MHZ or 20 MHZ is
> pretty much the same ball park.
>
> Patrick Robin
>