Re: Software for Central Heating Control

[meow2222@xxxxxxxxx]

Andrew Gabriel wrote:
> In article <1136370249.442615.10950@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
> 	meow2222@xxxxxxxxx writes:

> > For the computer side of things, I would steer well clear of PCs, as
> > you need a system that will stay running for years at a time, and PCs
> > simply dont have the necessary hardware or software reliability. My
>
> Um, they do, providing you aren't running anything Microsoft-based.
> I run my system on an old 120MHz Pentium (which is still _way_ over
> powered for the task) using Solaris x86, and it has never gone down
> except when there's a power cut, which is roughly once every 400
> days so far.
>
> > And, as has been said, the system must fail to functional. If it
> > doesnt, youre buying yourself a whole lotta trouble downline, and
> > trouble costs money.
>
> Or fail-safe and alert you, which is what mine would do (hasn't
> ever done so yet, except when deliberately engineered to do so
> to test it works correctly). I also watchdog the system from the
> burglar alarm, which will alert me if it fails, and can remotely
> reboot it if required (again, never required as yet).


The point of 'fail to functional' is that the computer isnt relied on
at all, and if it dies you dont have a problem to solve. I would not
want to rely for the coming 30 years or more on the right person being
there at the right time, remembering the right things and having the
right kit. Imho its important that the system continue working,
presumably with a more basic control system. If not set up this way,
youre just building in a problem.

A way to achieve this is to use a simple hardware control system and
use the secondary PC system to tweak the first control system. If the
PC dies, no further tweaks, it keeps running, with more basic control.


NT