[Nut-upsuser] 24V DC ATX PSU with limited UPS functionality over USB

Jean Delvare khali at linux-fr.org
Thu Mar 13 21:50:43 UTC 2008

Hi Michelle,

On Tue, 11 Mar 2008 16:22:09 +0100, Michelle Konzack wrote:
> Hello Developers and *,
> I am working on a "24V DC ATX PSU" for Photopholtaik Systems which can
> have input voltages from 18V to 27.7 Volt and is entirely modular,
> which mean, you can select the desired module/s (up to 6) from ATX
> (96/144/240/300W), P4 (144W), SATA (82/305W) and Device (34/68/136W)
> And last not least, I want to build a "PowerWhatch" module which should
> be connected from the PSU to an internal USB port of the mainboard.
> Currently I do not know, whether I should use Maxims 1-Wire chips like
> the DS2450 which has four AD-Converter or a I²C/SMBus solution.  Both
> will work with the DS80C411 Microcontroller...
> Now the question to you:
> Since I do not want to reinvent the wheel, I like to use existing
> programs where I think, NUT is the perfect solution...  The problem is,
> HOW I have to deliver the data to it or how must I provide it?
> The "PowerWhatch" module picks only the Voltage and Amperes and
> Temperature from each of the 11 modules... and maybe it will store them
> for a while in a 8-16 kByte NV-RAM or something like this...
> If you have ideas or suggestions, please let me know.

Given that you are working on a PSU and not a UPS, I am not sure that
nut is the best tool to interface with. Wouldn't it make more sense to
add one or more hardware monitoring chips in your PSU and connect them
to the motherboard's SMBus, and use a hardware monitoring driver in the
kernel to monitor all the values you are interested in? There are many
popular chips already supported by the Linux kernel, which can monitor
several voltages, temperatures and/or fans. And then there's a library
for applications to access the data easily.

Just my 2 cents of course, depends on what you want to do exactly.

Jean Delvare

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