Re: [CAD_CAM_EDM_DRO] Re: counting encoder holes ? BEST encoder range ?

turbulatordude wrote:

>I have 4 of these and have not put power to any of them as yet. I
>did trace out to the one capacitor on board and it goes to pin 8.
>With ground on pin 4, I assume it is powered on pin 8 like other IC's.
>
>
>

OK, sounds like you've got it.

>My next question is...
>
>What is the BEST encoder range ?
>
>I read 800 (200 quadrature) often, but am not sure if that is the
>minimum or optimum.
>
>I have a 2,000 (2,000 quadrature-8,000 pulse) that was advised as too
>sensitive.
>
>The encoders I have are 500 quadrature, 2,000 pulse.
>
>

Encoder count, by itself, is meaningless. What you need to know is
counts per
unit of movement (Inches, in the US). So, if you have 2000 counts per
rev directly
connected to a 5 TPI leadscrew, that is 10,000 counts per inch. To move
at 60 IPM
(one IPS) you need 10,000 step pulses per second into a Gecko 320
drive. Any
software package should be able to handle that with no effort.

Now, if you have the 8000 count/rev motor-encoder unit on a 4:1 belt
reduction and
a 5 TPI leadscre, that will be 8000 * 4 * 5 = 160,000 counts per inch!
If you want to
move at 120 IPM (2 IPS) you need 320,000 step pulses per second. This
is CLEARLY
out of the range of any software-generated step pulses. You will need
hardware to
generate step pulses that fast. Or, you'd need to change to a
lower-resolution encoder,
or go to a Gecko 340. But, the Gecko can't go over 250,000 encoder
counts/second,
so you'd get positioning errors if you tried to go that fast.

Jon