[Nut-upsuser] APC Backups Pro Low Batt

[Charles Lepple]

[please keep the list CC'd - other people more experienced with
genericups may be able to help.]

On 5/12/06, Rabie Van der Merwe <rabievdm at gmail.com> wrote:
> I also think I have found my original problem, I have a pullup resistor from
> CP to the lowbatt line,
> however because of the APC design they have a open collector design pulls
> the signal to GND
> once the batt level is low, now the problem is due to the comm port design a
> low signal is actually
> a negative voltage on the input.
>
> So what I would have to do it use the CP then put that through a inverter,
> feed that to the batlow pin,
> then once the ups pulls the signal to GND that should register as a high
> ....
> Or maybe I shouldnt use DCD ... I need to reread up on how all the pins on a
> commport works

The idea with the CP configuration parameter (as well as for the other
signals) is that you can set CP=-RTS (instead of CP=RTS) if you need
the power pin to be negative.

> Why o why couldnt APC have just set the output to High is the batt was good,
> and low if the batt was low ?? :)

Because it is just a relay contact on the UPS, not a RS-232 driver.

-- 
- Charles Lepple