[OpenTRV-interest] OpenTRV board as 868MHz transceiver

[Marko Cosic]

On 10 January 2016 at 09:33, Damon Hart-Davis <damon at opentrv.uk> wrote:

> Our intention very soon (I am working on the security code right now) is
> to allow to you to tell each OpenTRV unit what temperature you want to be
> at, overriding its internal logic.  (It would revert to that internal logic
> if/while it lost the radio link.)


In time COHEAT will adopt this setup with internal logic to suit our needs.


We could also override a COHEAT-style override of the percentage open for
> the valve, but then you would have to close the temperature control loop in
> real time.


We only did this for the experimental system because it's faster to develop
control algorithms centrally on gratuitously over-powered computing
hardware than it is to be very devious on low power hardware.


Not impossible, but not recommended unless your day job is developing
> control algorithms (as is COHEAT’s!). That control loop is tricky and you
> risk eating up bandwidth and batteries if you keep that loop tight enough


Agreed.

If your heating system runs weather compensated and is well balanced* then
the TRV should do very little. Anything else and you're working hard to
maintain room control.

*If you can remove all TRV heads and the radiator outputs closely track
outdoor conditions such that the internal temperatures are stable and
return temperatures from each radiator are similar then this is well
balanced. Most systems are nothing like compensated or balanced.


So, the upshot is that two-way control is on its way, but we don’t want to
> do it until we can do so securely.
>

Otherwise you'll end up with more than one user doing silly things with it.
;-)
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.opentrv.org.uk/pipermail/opentrv-interest/attachments/20160111/c0568e96/attachment.html>