Re: [CAD_CAM_EDM_DRO] Re: mounting encoder with pulley

Hi Caudlet,

You might be right! But as I seem to remember using two F/Fs driven by
exclusive OR gates to decode quadrature signals, it occurs to me that
several stages of counters could be cascaded, and the "slower" stages
would count the same, just slower. A state machine, if you will. So a
long counter could be set up in a PAL or PLA, and operated with a state
machine. The count should probably be divided by a binary power. A
divide by 4 seems about right for me.

Alan KM6VV


caudlet wrote:

>
>>I know there are difficulties - that's why I've responded to
>
> several
>
>>people saying that input multipliers are the better answer. I do
>
> have a
>
>>situation that suggests using an encoder divider, though.
>>
>>The method I would use would be to do the full 4X decoding (or
>
> possibly
>
>>just use the encoder phases as step and direction signals, giving a
>>"free" divide by 4), then divide down the resulting count. This
>
> counter
>
>>would then drive a set of quadrature signals - essentially, I would
>>decode the encoder pulses, divide the decoded count, then output a
>
> set
>
>>of faked quadrature signals with the divided count. I think I
>
> would do
>
>>this with a microcontroller, so I could have better control of the
>>divide ratio, and different options for output. It's probably
>
> possible
>
>>in discrete logic, but I'm a software guy. :)
>>
>
> Awh, you software guys are all the same ! 9;-) I think in terms of
> hardware being from that school then add in software to do things
> that are not economically done in hardware. I think I would start
> out with a simple divided by 10 chip or something like a CD4029
> presetabble counter) and be able to pick off the divide ratio I
> wanted. Divide each signal then recombine them to give you the
> quadrature signal. As long as the timing relationships (both signals
> go through the same signal conditions) then it might work. It would
> take some time with a plug board and a dual trace scope but it just
> might work.
>
> I know its a PITA to remove/add/modify stuff on the motors but that's
> what we HSCNC'ers do! We trade our (low cost) labor for just buying
> the right motor/encoder to begin with. I spend most of my time
> designing and making special brackets and plates so I can use the
> surplus stuff I have scrounged!
>