Re: [CAD_CAM_EDM_DRO] Re: mounting encoder with pulley

HI Caudlet,

Well, if it's that simple, fine! The simplest solution is often the
best solution. I would've thought it more difficut then that.

Now to get some G340s.

Alan KM6VV


caudlet wrote:

>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, Alan Marconett <KM6VV@a...>
> wrote:
>
>>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
>>
>>
>
> Gee, PAL's and PLA's and all that stuff! I would just grab a CD4015B
> Dual four bit shift register (about 50 cents) and pick a divide by 2,
> 4, 8, or 16 output. The encoder just puts out two 90 deg phase
> shifted square waves and turning it into quadrature is the work of
> internal circuits. If your line count was 1000, then each channel
> puts out 1000 pulses. If you divided each by 4 then you end up with
> 250 each and back to 1000 in quadrature. Use the divide by 8 and you
> are down to 500 in quadrature. As long as you kept the 90 phase shift
> it should work out. One chip. You might have to use an LS type chip
> if the RPM of the motor was very high.
>
> Of course you could use a PIC and spend 4.00 bucks and hours writing
> a program to do the same thing and it would be really neat. I am at
> the stage in my design career where 'really neat' has been replaced
> with 'do it fast and cheap' so I have more time to make chips.
>