Re: [CAD_CAM_EDM_DRO] MAX speed of an rotary encoder

Patrick J wrote:

>Hi, i wonder howto find out the max speed i can run the encoder at
>

If the manufacturer doesn't spec it, or you can't get their specs, you
will have
to test it yourself.

>Also what circutry is needed to make sure I get the best possible flanks
>from it? (lesser speed could be due to a bad interface?)
>
>

Flanks? I certainly don't understand you there.

>I havent been able to find a datasheet for my encoders. I tested them
>a while back, but got lesser speed than I expected. (around 1k rpm)
>Should the encoder outputs sink, or source?
>
>
>

Most encoders, if designed for machine motion systems (as opposed to hand-
operated panel encoders) should be able to do much better than 1000 RPM.
Most will handle at least 100,000 counts/second. Some encoders are open-
collector, and need a pull-up resistor to +5 V. These would be sink-only
outputs. I haven't run across source-only outputs, but that doesn't
mean they
don't exist. They would require a pull-down resistor to ground.

Most encoders, especially those that run from +5 V, have outputs that
drive both high and low, but in soma cases they benefit from pull-up
resistors, too.

You have not told us what encoders you have, what circuitry you are using
to interface them, or what the nature of the problem is. Do you have
an oscilloscope? (Sounds like you probably don't.) They are really
useful for diagnosing this sort of problem.

Jon