Re: RTLinux vs RTAI and EMC

["Tim Goldstein" <timg-at-ktmarketing.com>]

Agreed that planning ahead is a good thing. Unfortunately as hobby users we
are often dealing with surplus and need to make what we have work. I also
agree that you can make it work by using a G340, but in all reality that is
just a way to compensate for the software's ability to generate a high
enough pulse ratio and is achieved by degrading the performance of the
system. As Jon E. so often likes to point out anything driven with discrete
steps will exhibit stair stepping on long tapers and large circular moves.
Using a G340 does not improve the results, but using a G320 (or the G340 in
1:1 mode) and high resolution encoders does. Unfortunately it is at the cost
of reduced rapids particularly with freqmod.

All in all it is a balancing act. I think for step and direction servos
steppermod does a better job of balancing the opposing demands.

Tim
[Denver, CO]

P.S. On Bridgett I was able to plan my encoder resolution to give a nice
result with G320s. I am set for .0001" steps on X and Y so I can easily
achieve 120 ipm.

----- Original Message -----

>
> This is why I advise folk to do a bit of up front design.  It is also the
> reason I recommend the Gecko 340 rather than 320.  Not a lot of machines
even
> work to a quarter thou.  Make that a 2x pulse multiplier or a 1 to 1 ratio
> and a machine is running about as fast as your Bridgett.
>
> Ray
>