Re: [Emc-users] Free Form Motion - G-code question

[Andy P. <an...@an...>]

On 13 September 2010 13:27, Spiderdab <77...@ti...> wrote:

> ooops.. maybe i've forgot to try to increase that value. so you think
> that with a ferror of something like 20, i can reach lower accelerations
> without errors?

I would expect so, but you would need to test it.

> other question: why in EMC i can set every single joint acceleration,
> and i can't set the world mode acceleration? or is it possible?

The axis acceleration limits are to account for the mechanical limits
of the actuators. They are actually _joint_ limits, you will have one
per motor, despite only having a 3-axis cartesian space.
In your case the physical acceleration limits are likely to be
different depending on the string angles and hence the "apparent"
inertia of the load. I would guess you need to test each motor with
the string as close to horizontal as it will ever get.

You can't set world-mode acceleration because the assumption is that
in a machine tool you want to get to programmed speed as fast as the
slowest-accelerating axis can manage. I think you are likely to be the
first person ever to want to vary acceleration in world-space in EMC2.

-- 
atp