I've asked a retired physics professor friend for some enlightenment. 
 
Jon Elson has stated that with T = r x Fsin(theta) and  F=ma that the 
acceleration is Gravity because it's equivalent to dropping the X axis table 
and letting the earth accelerate it.
 
But F=mg is the force due to gravity.  I might well be that since we're dealing 
with horizontal motion here that the acceleration value is different so we're 
talking about F=ma.  
 
We know the Force because we know the torque and the effective radius and that 
the force is perpendicular so sin(theta) is 1 and can be ignored.   We know the 
mass.
 
When we set up MAX_VELOCITY and MAX_ACCELERATION in the ini file the velocity 
is in in/sec.  The acceleration we don't know.  We can keep trying values until 
the servo drive reports a following error because the step pulses have exceeded 
the encoder pulses by the preprogramed alarm point.  Then back off until we are 
comfortable.  And if the motor isn't connected then it spins up way faster than 
when it has to move the table.
 
But does the accel value in F=ma have to be gravity?  And if not, what then?
 
John Dammeyer
 
 
> -----Original Message-----
> From: Bari [mailto:bari00...@gmail.com]
> Sent: July-22-20 9:21 PM
> To: emc-users@lists.sourceforge.net
> Subject: Re: [Emc-users] Calculating table acceleration. Was: Need help with 
> Bostomatic BD18-2 to linuxcnc
> 
> 
> On 7/22/20 11:04 PM, Bruce Layne wrote:
> >
> > On 7/22/20 11:43 PM, Thaddeus Waldner wrote:
> >> 1g = roughly 32in/s^2
> > 1 g is 32 ft/sec^2
> >
> > Feet, not inches.
> >
> 
> Comparing Standard Gravity to Other Acceleration Units
> 
> Standard Gravity��� 1 G's
> Meters per Second per Second��� 9.81
> Feet per Second per Second��� 32.174
> Inches per Second per Second��� 386.09
> 
> 
> _______________________________________________
> Emc-users mailing list
>  <mailto:Emc-users@lists.sourceforge.net> Emc-users@lists.sourceforge.net
>  <https://lists.sourceforge.net/lists/listinfo/emc-users> 
> https://lists.sourceforge.net/lists/listinfo/emc-users

_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Reply via email to