GERRY COX wrote:
>
> XYGAX wrote:
> >>
> >> Paint a white line on the flywheele and use one of those reflective opto
> >> switches then count pulses it also has the advantage of being a non
> contact /
> >> no mechanics interface
> >>
> >> Cheers Steve.....
>
> >Most Industrial sensors don't respond above 500Hz
> >this is done to limit noise
> >peter@cousens.her.forthnet.gr
>
> Peter,
> However, most diesel engines don't respond (for long)  above 500Hz * 60secs
> = 30,000 RPM
> This is also done to limit noise  :-)
> Gerry Cox
>  ----------

Sorry I should have said response time of 1msec
which = max 500Hz given a symetrical input
under poor conditions less (dirty line/lens)

Paint half the flywheel white and half black
and it should work
but the fan would be close or past the limit

But the point that I'm making is that a standard sensor
has limits that WILL apply in this case

I HAVE use industrial sensors in similar situations
and I am aware of their limits

Peter
--
If God so loved the World (and created it)
then why is it so imperfect
It's got more bugs than windoze 95

peter@cousens.her.forthnet.gr