[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]
Re: [ATM] Looking for the best PWM cycle time for dew heaters
Hi Don,
I like the "closed loop" nature of this design. Very efficient. The only
problem is that I would need to build a controller per object to be
heated. Hehe...
Anyway, I did have one question. The introduction in your document
mentions secondary's, correctors, eye pieces etc... I'm thinking of
building a Newtonian with an open truss. Do you see any issue with
warming the primary? Or were you just thinking of closed tube designs at
the time?
And Larry,
Thanks for the heating element ideas.
Thanks
-Anthony
> -----Original Message-----
> From: atm-bounces@atmlist.net
> [mailto:atm-bounces@atmlist.net] On Behalf Of Don Clement
> Sent: Thursday, April 05, 2007 8:28 AM
> To: atm@atmlist.net
> Subject: Re: [ATM] Looking for the best PWM cycle time for dew heaters
>
> Here is a DIY dew heater control that automatically keeps
> optics a small amount above ambient. PWM is not time based
> rather based on the difference of optics temperature and
> ambient temperature. This assures the minimum possible heat
> and battery power is used for minimum effect on seeing.
>
> http://www.clementfocuser.com/images/Temperature_Control_Print.pdf
>
>
>
> Don Clement
>
> Running Springs, California
>
>
>
> > Has anyone figured out the best pulse width modulation
> (PWM) time for
> > a dew heater controller? Specifically, how long should one
> 100% cycle be?
> > If it were too long the dew heater would noticeably cool off before
> > heating up again (running at less than 100%), but is too short a
> > problem, say a few dozen cycles per second? I was thinking
> of using a
> > PIC16F88 (yes, a 555 could do it also) and some IRF510s as
> the 12v switches.
> > Thanks.
> >
> > Allen
>
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
>
_______________________________________________
ATM mailing list http://www.atmlist.net/