Re: [CAD_CAM_EDM_DRO] encoder steps

Aaron Bott wrote:

>
> I have 250 physical step encoders on the mill I am converting. As these read by 4 channels A, not A, B, not B does this mean that there are effectively 1000 actual steps - ie 1 rpm = 1000 steps ?
>
> thanx
>
> Aaron

Hello Aaron,

Short answer = yes.

Digital encoder detection circuitry usually monitors the 2 signals (A
and B) you describe. This permits 4 times the resolution compared to the
number of marks on the encoder. More importantly, a pair of detectors
can tell which direction the encoder is moving.

If you are looking at A and B outputs they will have the binary gray
code sequence 00, 01, 11, 10, 00 moving in one direction and 00, 10, 11,
01, 00 moving in the opposite direction.

So the circuitry can count up or down in quarter steps according to the
direction of rotation.

Having the complement of each signal provides no additional info but
does provide a lot of electrical noise immunity if differential
receivers are used wherever the signals are received.

Tom Hubin
thubin@...