On Sun, Jan 10, 2010 at 12:05 PM, Sophana K <[email protected]> wrote:

> Hi
>
> I'm using owfs 2.7p5-3 on openwrt kamikaze 7.09 on an asus wl500g
> deluxe to control my heating system with a python program.
>
> That version is a little old but the simultaneous functioning shouldn't
have changed that much.


> I actually have between 10 to 15 temperature sensors to read and have
> a performance problem.
> Some sensors are powered some are not.
>

That might be a problem. There isn't enough current in the data line to fuel
simultaneous parasitic-powered  temperature conversions.


> I'm using 2 hobby board hubs and would like to enable simultaneous
> temperature reading for at least the one sensors that are powered.
> owfs is a client of owserver which uses usb.
>
> I found no documentation on this. On the web site doc, the
> simultaneous section exists but is empty. I found a mailing list
> archive that said: write 1 to /simultaneous/temperature then read the
> temperature sensors normally.
>
>
> My big problem I had: I don't have the /simultaneous directory when I
> "ls" in the owfs directory. But when I do 'ls simultaneous', the dir
> exists!
>
>
The directory is only listed when there is a relevant device on the bus.
(But the directory is valid, just hidden). I was perplexed until I saw in
the next section that you have a DS2409 microhub.


> I also found out that there is a simultaneous dir on each "main" and
> "aux" dirs for the hubs.
>
> So I tried to do this (these are powered...)
>  echo 1 > simultaneous/temperature;cat
> 1F.C4DC03000000/aux/28.C4027E010000/temperature;  cat
> 1F.C4DC03000000/aux/28.0D337E010000/temperature
>
> the reading works but it is slow. the first write clears the cache.
> I tried this
>
> echo 1 > simultaneous/temperature;echo 1 >
> 1F.C4DC03000000/aux/simultaneous/temperature;cat
> 1F.C4DC03000000/aux/28.C4027E010000/temperature;  cat
> 1F.C4DC03000000/aux/28.0D337E010000/temperature
>
>
echo 1 > 1F.C4DC03000000/aux/simultaneous/temperature
is technically correct, but honestly never tested. I'll have the review the
code and test.


> It is quite fast, but the temperature never changes. It is always the
> cache value that is read, and it is NEVER updated.
>
> Thanks for the report. Sounds like a bug.

Paul Alfille
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