Re: [CAD_CAM_EDM_DRO] Rotary Pulse Generators ?

jimalb2309 wrote:

>Hello to all;
> These where advertised as 2 channel RPG's, with IR emitter and
>photo logic detectors which output 5v logic level.
>My question is what are they, and can they be used like encoders?
>they have what looks like an encoder wheel inside. if i look close
>through the two holes in the case i can see the slots in the disk,
>one set seems to be coarse and the other set seems to be fine, theirs
>a small circuit board with the transmitters and receivers with a
>resister and capacitor and looks like maybe a couple of trimmer pots,
>(assume for adjusting the sensitivity), and four wires red, black,
>orange and brown, assume red and black power and ground, and brown
>and orange the two channels.
>
>

MPGs (manual pulse generators) are very much like encoders. The major
differences is they are not necessarily designed to accept fast movement,
the bearings may be designed for a relatively low number of revolutions,
and they are almost always of low resolution, typically 25 or 100 cycles
per revolution, so that they produce 100 ticks per rev to the CNC
control. Given these limitations, you COULD use them as encoders
in some circumstances.

The coarse and fine tripes sounds quite odd. Generally, the two
channels of an encoder or MPG are the same number of pulses per
rev, but displaced by 90 degrees relative to the pitch of the stripes.
This allows the decoder to determine direction. If the two channels
are actually different pulses per rev, I don;t think you'll be able
to do much with these.

Jon