Re: [CAD_CAM_EDM_DRO] Encoder count selection for G320

HI Art,
thanks for the info, that's just what I was hunting. I looked for Turbocnc
maximum step pulse rate but can't find it. I will try posting in CNCPRO and
EMC2 user groups also unless I find the max step pulse rate for them too.
regards
Denis

On Saturday 14 February 2009 11:39:26 Art Eckstein wrote:
> Denis,
> Mariss sent this to me a few years ago. I think it is what your looking
> for?
>
> "Determine what is your software's maximum step pulse rate. It'll be
> published somewhere. Convert your motor no-load RPM into revs per
> second (divide RPM by 60) and divide that by 4. Divide that into
> your software's max step frequency. The result will be the maximum
> encoder line count. Pick the next lowest standard mfg encoder line
> count. In other words, if your result is 566.66 lines, pick a
> 500-line encoder. "
>
> Hope this helps.
>
> Country Bubba
>
> At 02:25 PM 2/14/2009, you wrote:
> >Hi Dan,
> >I meant 30 ips not 30 ipm. Encoders arm mounted on motors. I got
> >some feedback
> >that mentioned about 18 ips would be a better target and that's the range
> > I want to target. I'll use a gearhead to divide the speed down by 7 to 60
> > revs per second.
> >There is a relationship between PC software output pulse generation and
> >encoder line count that has a bearing on top speed. I can not find
> >the article
> >that mentions how to decide whether the line count is a good choice.
> >Would you
> >have any information on how to make that choice?
> >regards,
> >Denis
> >
> >On Tuesday 10 February 2009 08:00:01 Dan Mauch wrote:
> > > You must have made a mistake when you said that you wanted 30 IPM I
> > > think you meant 300 ipm. With a 4200 RPM motor and a 3/1 reduction with
> > > a .891 pitch diameter of the 14xl pulley you would have
> > > 4200/3X(piX.891)=3918 IPM negating other factors. That is a tad too
> > > fast. You should look to increase the reduction to at least 6/1 . You
> > > can also lower the top runaway speed by using a lower voltage power
> > > supply. With your current setup and the encoder on the motor shaft I
> > > would say that the resolution using a 250 line encoder would adequate
> > > and give you plenty of speed and not a high number os steps per in that
> > > the programs you mention would be fine with. Dan Mauch economical 3D
> > > scanner software and kits
> > > low cost stepper and servo motors.
> > > cases for Gecko drives
> > > kits and assembled 3-4 axis drives
> > > www.camtronics-cnc.com
> > > www.seanet.com/~dmauch
> > > ----- Original Message -----
> > > From: dcassyc1
> > > To: CAD_CAM_EDM_DRO@yahoogroups.com
> > > Sent: Monday, February 09, 2009 9:15 PM
> > > Subject: [CAD_CAM_EDM_DRO] Encoder count selection for G320
> > >
> > >
> > > Hello all,
> > > I want to use homeshopCNC servo motors on a router. The motor is
> > > rated 72VDC and 4200 rpm no load speed, 850 in oz peak torque, 170 oz
> > > in continuous torque. My plan for the gantry drive is to go from the
> > > motor through a 1:3 reduction and drive a jackshaft with 14 tooth XL
> > > gears on each end, which rack over stationary belts fixed to the frame.
> > > I calculated the gantry mass at 175lbs aprox. I'd like to achieve 30
> > > ipm traverse speeds for the gantry and carriage. Is that an unrealistic
> > > speed?
> > > I don't know how to make the choice between 250 or 500 line
> > > quadrature encoders. The 'files' sections servo motor files were empty.
> > > From what I remember, top speed depends on pulse throughput from the
> > > PC. The control software is CNCPRO, Turbocnc, and EMC. Would the 500
> > > line encoder provide greater precision?
> > > Would anyone care to show me how to make the line count selection for
> > > the Gecko G320 and advise on the PC speed/performance requirements?
> > > TIA
> > > Denis