Re: Pump monitoring (again)

["Chris Purves" <CHRIS_PURVES@xxxxxxx>]

The voltages are not connected - make sure you check the relay can
handle the amps!

They are very simple things. The only thing that gets you is
mechanical bounce when the relay is triggered but should not be an
issue on a pump. More an issue if like me if you are counting pulses
from a relay (my electricity meter triggers a relay for every .1kwh )
- the sampling circuit to determine a pulse has happened must
understand relay debounce etc.

C

--- In ukha_d@xxxxxxx, "Benfield, John \(Penta\)"
<john.benfield-eds@...> wrote:
>
> I need someone to confirm my understanding of how relays work and will
> do what I am expecting.
>
> In my quest to monitoring my central heating I am looking at a way of
> monitoring when the various pumps come on. I already have a hardwired
> controller that links all of the timers/thermostats/pumps together.
The
> controller has a screw terminal block within it and I have worked out
> which terminals go live for each pump. What I *think* I now need it a
> 230v relay attached to these.
>
> My really really basic understanding of a relay (such as this
> http://tinyurl.com/kwtd2) is that when
a voltage is applied across one
> set of contacts, the pair on the other side of the relay either open
or
> close. Am I correct in assuming that the 230v does not get passed
> through the relay to the second contacts - this will destroy my 1-wire
> sensors.
>
> Looking at the various relays out there I guess I need a DPDT 5a 230v,
> does this sound correct?
>
> JB
>
>
>
> [Non-text portions of this message have been removed]
>