So, when are you going to stop talking smack and design one?

For all digital I would use a PIC chip and not LabView because LabView is
over kill. The package was designed for the test environment & runs on a PC,
at least with the applications I've used it in.

For all analog I would use a few timers and a simple counter. No pots or
anything else to set once the design was done.

Tom
www.stir-plate.com

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf Of
Alistair Bell
Sent: Sunday, April 25, 2010 12:54 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: PWM controller , was Water Cooler System Design Flaw
Workaround?

Sure Tom, those parameters are good and all, but is it really that much less
complicated than an old school  controller with pots for slope, offset etc?

or, lets all go modern and run it off a custom made control strategy built
in LabView, a laptop and a D->A interface.

:)

I really need to stop lazing around talking smack ,

cheers

ab

On 25-Apr-10, at 10:46 AM, Tom Hargrave wrote:

Yes, we are talking PID now and I can probably design something that would
do the job. I suspect you could too since you brought up PID.

But I wonder if the solution can be done a little less "high tech"
and all
12V powered?

For example, there are a set of known parameters for pulling a long
hill:

1. You would want to know that the transmission was not in high gear.
2. You would want to know that the engine was above a certain RPM, let's say
above 3500 RPM for arguments sake?
3. You would want to know that the engine was making power - throttle open &
not coasting down a ling hill in lower gear to conserve breaks.
4. You would want to know that the vanagon met these two parameters for a
specific period of time - maybe 15 seconds?

Once these four tests were met you would switch on the fan or an auxiliary
fan to pull all the heat you could from the radiator.

Once test 1, 2 or 3 were no longer true for 15 seconds, you would switch the
auxiliary control off. If this were a separate auxiliary fan it would turn
off but if it were the main fan the fan would still be managed under the
vanagon's system control.

Tom