The Papst fans that I have used with pulse speed feedback have used an
open collector output. You need to add a 10k or so pull-up resistor to
get a pulse output. I think we used a 5V supply for this (not the 12
or 24V main fan supply voltage).

RP

On 4 July 2010 09:10, Philip Pemberton <piclist@philpem.me.uk> wrote:
> On 03/07/10 21:00, KPL wrote:
>>> =A0 =A01) It's a "Variofan", and that line varies the fan speed
>>
>> No, text on fan says "+ red -blue sensor white" which corresponds to
>> the colors of the three wires. Fan speed changes with changing
>> pwm/voltage nicely.
>
> Um... that sounds like a Variofan to me. "Sensor" would be the little
> thermistor the fans come with.
>
>> Yes, I know there are other ways to detect rotation, but the main idea
>> was to build a controller usable for any fan with tacho wire, to avoid
>> any adjustments and calibrations.
>
> A peak/trough detector and a couple of opamps would eliminate the need
> for any 'adjustments or calibrations'...
>
> --
> Phil.
> piclist@philpem.me.uk
> http://www.philpem.me.uk/
> --
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>

-- =

http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist