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Re: [APD] Fw: Re: Ph controllers (was Re: CO2 System)
Well, okay, let's try to get all the opens and closes and
ons and offs in order.
I was referring to the relay in the controller. When the
circuit is *open*, that's off. A closed circuit is one
through which current can pass. When the controller circuit
is closed, then current is passed to the solenoid and
(assuming the solenoid is normally a closed (mechanically)
valve, then the electromagnetic action of the solenoid,
once current is passing through it, will pull the solenoid
valve open and allow CO2 to pass through the valve.
In mechanics, closed is "off." But in electrical circuits,
closed is "on."
--- Cynthia Powers <mscyn at earthlink_net> wrote:
> -----Forwarded Message-----
> From: Russell Vance <russell_vance at gmail.com>
> Sent: Nov 19, 2005 9:45 AM
> To: "aquatic-plants-owner at actwin_com"
> <aquatic-plants-owner at actwin_com>
> Subject: Re: [APD] Ph controllers (was Re: CO2 System)
> You got that backwards. They are normally closed and the
> controller turns
> the solenoid on (open) when the pH gets above the set
> point, and turns off
> (closes the solenoid) when it gets below the set point.
> If it turned on when it got below a set point, it would
> turn the co2 on,
> thus lowering it more, then it would never turn off.
> On 11/19/05, S. Hieber <shieber at yahoo_com> wrote:
> > >
> > > A pH controller turns on/off whatever device you
> attach to
> > > it. Fo aquatic gardening purposes, they are normally
> > > circuit when the pH is above a set point and closed
> (or ON)
> > > when the pH is below a set point. If you connect a
> > > to the controller, CO2 will flow only when the pH is
> > > the controller set point and then will shut down when
> > > pH is above set point.
> Aquatic-Plants mailing list
> Aquatic-Plants at actwin_com
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