On Thu, 27 Oct 2011, doddm2001 wrote:
> I'm using a 7250 to monitor an HVAC run-times, to
characterize power
> consumption. It boots into Debian over NFS from our
home network server.
>
> The server is on a UPS, and if power fails, it shuts
down sanely after a
> few minutes. But the 7250 is not on a UPS, so it
would just die when
> power fails.
>
> In another application, I booted into TS-Linux and
mounted everything
> read-only,, but I can't do this with the HVAC monitor
-- it writes to
> files on the server.
>
> My program opens and closes each file for every write
operation, so there
> are no continuously-open files hanging around waiting
for the power to
> fail.
>
> Am I at risk of corrupting the server's file system
if the 7250 dies? If
> so, what should I do to protect it?
Add your own backup supply.
On the 7260 5 or 6 AA NiMH cells, a couple of diodes, a
resistor and a
spare ADC port and some code are really all that are
necessary. I believe
the 7250 needs a regulated 5V supply like the 7200?
On my 7200 I have a DC-DC 1A converter provide power fed
from a 12V DC wall
wart, and 6 AA NiMH cells, a couple of diodes, a resistor
and a spare ADC
port and some code. When the 12V from the wall wart
disappears the NiMH
cells provide power, the code sees the 12V disappear and
does an orderly
shutdown.