Re: [CAD_CAM_EDM_DRO] Encoder count selection for G320

Denis,
Here is some information that I received from Mariss on this subject:

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.

Of course, this is if the encoder is mounted on the servo. If you
mount it on the screw, you will need to take any reduction ratio into
effect also.

Bubba



At 12:15 AM 2/10/2009, you wrote:

>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